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Transcript
P1 09 Red Shift 197 minutes 197 marks Q1. Describe, in as much detail as you can: • the evidence that the size of the observable Universe is changing; • the evidence that, billions of years ago, all the matter in the Universe was tightly packed together in the same place. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (Total 5 marks) Q2. Read the following information about cosmic microwave background radiation. Then use it to answer the questions below. (You may find it helpful to begin by deciding which items of information belong to which question.) (a) Explain, as fully as you can, why the frequency profile of electromagnetic radiation is an indication of temperature. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (b) Describe, in as much detail as you can, what cosmic microwave background radiation is and how it was discovered. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (c) Explain, as fully as you can, how cosmic microwave background radiation fits in with the idea that the Universe, as it now is, began with a big bang. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (4) (d) Some people think that Penzias and Wilson’s discovery of cosmic microwave background radiation was just lucky. Others disagree. What do you think? Give reasons for your answer. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (Total 12 marks) Q3. Explain, in as much detail as you can, the scientific evidence for the “big bang” theory of the origin of the Universe. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (Total 5 marks) Q4. What does the Big Bang theory state? In your answer you may include evidence for the theory. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (Total 4 marks) Q5. Astronomers use red shift in two ways. They calculate the distance to each galaxy from Earth. They also calculate the speed at which galaxies are moving away from Earth. The table shows some results. Distance is given in zettametres, Zm. One zettametre is 1021metres. Galaxy Distance from Earth to galaxy in Zm Speed at which galaxy is moving away from us in Zm per billion years Time the galaxy has been moving away from us in billions of years (Calculated by distance ÷ speed) Abell 963 25 000 1950 Abell 1302 14 000 1100 Abell 1314 4 100 320 12.8 Abell 1978 18 000 1400 12.9 Abell 2255 10 000 770 13.0 (a) 12.8 Complete the data for Abell 1302. (1) (b) Describe the relationship between the distance to a galaxy and the speed at which the galaxy is moving away from us. ..................................................................................................................................... ..................................................................................................................................... (1) (c) Explain how the data for time provides evidence for the theory that the origin of the Universe was a huge explosion (‘big bang’). ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (Total 4 marks) Q6. ‘Red shift’ is one of the pieces of evidence which led scientists to propose the ‘big bang’ theory. (a) Describe the big bang theory. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (b) To gain full marks for this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. Explain how red shift provides evidence for the big bang theory. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (Total 5 marks) Q7. Studies of light from distant galaxies have provided evidence for the theory that the Universe started from one place and is expanding. Explain how. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (Total 3 marks) Q8. Astronomers believe that the Universe is expanding. (i) How might the Universe have started? ..................................................................................................................................... ..................................................................................................................................... (1) (ii) State and explain briefly, one piece of scientific evidence which may be used to support this belief. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (Total 3 marks) Q9. Explain how observations at the red end of the spectrum of light from galaxies have led to one theory about the origin of the Universe. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (Total 6 marks) Q10. The Big Bang theory attempts to explain the origin of the Universe. (i) What is the Universe? ..................................................................................................................................... ..................................................................................................................................... (1) (i) What are the main ideas of the Big Bang theory? ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (iii) What is thought to be happening to the size of the Universe? ..................................................................................................................................... (1) (Total 4 marks) Q11. The Big Bang theory attempts to explain the origin of the Universe. (i) What is the Big Bang theory? ..................................................................................................................................... ..................................................................................................................................... (1) (ii) What can be predicted from the Big Bang theory about the size of the Universe? ..................................................................................................................................... (1) (Total 2 marks) Q12. (a) The light spectrum from a distant galaxy shows a red shift. What is meant by red shift and what does it tell us about distant galaxies? ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (b) What name is given to the theory that the Universe started with a massive explosion? ..................................................................................................................................... (1) (Total 3 marks) Q13. (a) A student listens to the sound waves produced by a car siren. When the car is stationary, the student hears a constant frequency sound. Describe how the wavelength and frequency of the sound waves heard by the student change when the car is driven away from the student. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (b) Satellites fitted with various telescopes orbit the Earth. These telescopes detect different types of electromagnetic radiation. Why are telescopes that detect different types of electromagnetic waves used to observe the Universe? ..................................................................................................................................... ..................................................................................................................................... (1) (c) In 2005 a space telescope detected a star that exploded 13 billion years ago. The light from the star shows the biggest red-shift ever measured. (i) What is red-shift? ........................................................................................................................... ........................................................................................................................... (1) (ii) What does the measurement of its red-shift tell scientists about this star? ........................................................................................................................... ........................................................................................................................... (1) (d) Red-shift provides evidence for the ‘big bang’ theory. (i) Describe the ‘big bang’ theory. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (ii) Suggest what scientists should do if new evidence were found that did not support the ‘big bang’ theory. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (1) (Total 8 marks) Q14. The visible part of the electromagnetic spectrum from a star includes a dark line. This line is at a specific wavelength. The diagram shows the position of the dark line in the spectrum from the Sun and in the spectrum from a distant galaxy. (a) Explain how the spectrum ‘shift’ of the dark line supports the theory that the Universe began from a very small point. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (b) From data collected, a graph can be drawn that links the speed of a galaxy with the distance of the galaxy from the Earth. (i) How does the visible light spectrum from galaxy A look different from the visible light spectrum from galaxy B? ........................................................................................................................... ........................................................................................................................... (1) (ii) A third galaxy, C, seems to be travelling away from the Earth at about 60 000 km/s. Estimate how far galaxy C might be from the Earth, showing how you use the graph to do this. ........................................................................................................................... ........................................................................................................................... Distance between galaxy C and the Earth = …………….… million light years (2) (Total 6 marks) Q15. Light is given out by the Sun and a distant galaxy. (a) Compared to the light from the Sun, the light from the distant galaxy has moved towards the red end of the spectrum. (i) What name is given to this effect? ........................................................................................................................... (1) (ii) Complete the following sentence by drawing a ring around the line in the box that is correct. The fact that light from a distant galaxy seems to move towards the red end of galaxies are shrinking the spectrum gives scientists evidence that galaxies are changing colour the universe is expanding (1) (b) Scientists have a theory that the universe began from a very small point and then exploded outwards. (i) What name is given to this theory? ........................................................................................................................... (1) (ii) Which statement gives a reason why scientists think that the universe began with an explosion? Put a tick ( ) in the box next to your choice. At the moment it is the best way of explaining our scientific knowledge. It can be proved using equations. People felt the explosion. (1) (Total 4 marks) The ‘steady state’ theory was once a popular alternative to the ‘big bang’ theory. Q16. The ‘steady state’ theory suggested that the universe, although expanding, had no origin and it has always existed. As the universe expands, a small amount of matter is created to keep the universe looking exactly the same all of the time. (a) When considering the origin of the universe, what is the difference between the ‘big bang’ theory and the ‘steady state’ theory? ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (b) The light from distant galaxies shows a red-shift. (i) What is red-shift? ........................................................................................................................... ........................................................................................................................... (1) (ii) Why does red-shift provide evidence to support both the ‘big-bang’ theory and the ‘steady state’ theory? ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (c) The ‘steady state’ theory was important in encouraging new research into the universe. Suggest a reason why scientists were keen to carry out new research. ..................................................................................................................................... ..................................................................................................................................... (1) (d) Scientists can answer many questions about the universe, but not the question: ‘Why was the universe created?’ Suggest a reason why this question cannot be answered by scientists. ..................................................................................................................................... ..................................................................................................................................... (1) (Total 7 marks) Q17.(a) In 1929, the astronomer Edwin Hubble observed that the light from galaxies that are moving away from the Earth showed a red-shift. Red-shift provides evidence for the theory that the Universe began from a very small initial point. What name is given to the theory that the Universe began from a very small initial point? ....................................................................................... (1) (b) By measuring the red-shift, astronomers are able to calculate the speeds at which galaxies are moving away from the Earth and the distances of these galaxies from the Earth. The graph shows some of the data calculated by astronomers. 1 megaparsec = 3.09 × 1019 km The data from two galaxies, K and L, is included in the graph. What does the graph tell us about the two galaxies, K and L, and their red-shifts? ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (c) The Andromeda galaxy is not moving away from the Earth. It is actually moving towards the Earth. This means that the light from Andromeda shows a blue-shift. How do the wavelength and frequency of the light from Andromeda seem to have changed when viewed from the Earth? ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (2) (d) Although the early universe contained only hydrogen, it now contains many different elements. Describe how the different elements were formed. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (2) (Total 8 marks) Q18. The visible part of the electromagnetic spectrum from a star includes a dark line. This line is at a specific wavelength. The diagram shows the position of the dark line in the spectrum from the Sun and in the spectrum from a distant galaxy. (a) Explain how the spectrum ‘shift’ of the dark line supports the theory that the Universebegan from a very small initial point. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (b) Name one other piece of evidence that supports the theory that the Universe began froma very small initial point. ........................................................................................................................ (1) (Total 4 marks) Q19. Scientists have observed that the wavelengths of the light given out from galaxies that are moving away from the Earth are longer than expected. (a) (i) What name is given to this observation? ............................................................................................................... (1) (ii) Draw a ring around the correct answer to complete the following sentence. shrinking. This observation gives evidence for the idea that the Universe is not changing. expanding. (1) (b) The graph shows that there is a link between the speed at which a galaxy moves away from the Earth and the distance of the galaxy from the Earth. The positions of three galaxies, A, B and C, are marked on the graph. From which galaxy, A, B or C, would the wavelength of the light reaching the Earth seem to have changed the most? Galaxy ............................................. Give a reason for your answer. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (2) (Total 4 marks) Q20. (a) In 1929, the astronomer Edwin Hubble observed that the light from galaxies that are moving away from the Earth showed a red-shift. What is red-shift ? ........................................................................................................................ ........................................................................................................................ (1) (b) By measuring the red-shift, Hubble was able to calculate the speed at which the galaxies are moving away from the Earth. He was also able to calculate the distance of these galaxies from the Earth. The graph shows some of the data calculated by Hubble. (i) The data from two galaxies, M and N, has been included in the graph. The light from galaxy M has a smaller red-shift than the light from galaxy N. What does the difference in red-shift tell scientists about the two galaxies, M and N? ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (ii) The gradient of the line drawn on the graph gives a number known as the Hubble constant. The Hubble constant can be used to estimate when the universe began. Use the graph to calculate the value of the Hubble constant. Show clearly how you obtained your answer. ............................................................................................................... ............................................................................................................... Hubble constant = ............................................ km/s per megaparsec (2) (iii) More recently, data has been obtained from more distant galaxies. The results from the more recent data give a totally different value for the Hubble constant to the one calculated from the 1929 data. Which set of data, the 1929 or the more recent, is most likely to give the value closest to the true value for the Hubble constant? Draw a ring around your answer. 1929 more recent Give a reason for your answer. ............................................................................................................... ............................................................................................................... (1) (c) The Andromeda galaxy is not moving away from the Earth. It is actually moving towards the Earth. This means that the light from Andromeda shows a blue-shift. How do the wavelength and frequency of the light from Andromeda seem to have changed when viewed from the Earth? ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (2) (Total 8 marks) Q21. (a) Scientists use telescopes to observe stars and galaxies. Some telescopes are on Earth, but some are on satellites in space. Why do telescopes in space give better images than telescopes on the Earth? ........................................................................................................................ ........................................................................................................................ (1) (b) Scientists have observed that the wavelengths of the light given out from galaxies that are moving away from the Earth are longer than expected. (i) What name is given to this observation? Put a tick ( ) in the box next to your answer. blue-shift green-shift red-shift (1) (ii) Complete the following sentence by drawing a ring around the correct line in the box. shrinking. This observation gives evidence for the idea that the universe is not changing. expanding. (1) (c) Use the graph to answer the following questions. (i) What is the link between the speed that a galaxy moves away from the Earth and the distance between the galaxy and the Earth? ............................................................................................................... ............................................................................................................... (1) (ii) The positions of three galaxies, A, B and C, are marked on the graph. From which galaxy, A, B or C, would the wavelength of the light reaching the Earth seem to have changed the most? Galaxy ................................. Give a reason for your answer. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (Total 6 marks) The ‘Big Bang’ theory is one theory of the origin of the Universe. Q22. (a) (i) Explain what is meant by the ‘Big Bang’ theory. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (ii) The light arriving from distant galaxies provides scientists with evidence to support the ‘Big Bang’ theory. Explain how. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (b) At a meeting held in 2005, a group of scientists claimed that new data had been collected that showed the ‘Big Bang’ theory to be wrong. Other scientists said that there was no reason to doubt the ‘Big Bang’ theory. What should scientists do when a theory does not appear to be supported by new data? ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (2) (c) Scientists can answer many questions about the Universe, but not the question: Suggest a reason why this question cannot be answered by scientists. ........................................................................................................................ ........................................................................................................................ (1) (Total 7 marks) Q23.The diagram shows a teacher using a loudspeaker to demonstrate an important effect.The loudspeaker, which produces a note of constant frequency, is swung around in a circle. (a) As the loudspeaker moves towards the students, the frequency of the note heard by the students increases. What happens to the note heard by the students as the loudspeaker moves away from them? ........................................................................................................................ ........................................................................................................................ (1) (b) The teacher is using the demonstration to model the red-shift in light that is observed from most distant galaxies. (i) Which one of the following statements gives the main reason why models are used in science? Put a tick ( ) in the box next to your answer. Models can help to explain an effect or theory. Models can prove that a theory is correct. Models can help to generate new ideas. (1) (ii) Explain how this demonstration can be used as a model for red-shift. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (c) Red-shift provides evidence to support the theory that the Universe began from a very small initial point. What name is given to this theory? ........................................................................................................................ (1) (Total 5 marks) Q24.Optical telescopes may be used to observe galaxies. Some optical telescopes are on the Earth and some are on satellites in space. (a) How is the image produced by an optical telescope on a satellite in space better than the image produced by an optical telescope on the Earth? ........................................................................................................................ Give a reason for your answer. ........................................................................................................................ ........................................................................................................................ (2) (b) Scientists have observed that the wavelengths of the light from galaxies moving away from the Earth are longer than expected. This observation is called red-shift. (i) What does the size of the red-shift tell the scientists about the distance a galaxy is from the Earth? ............................................................................................................... ............................................................................................................... (1) (ii) Complete the following passage. Red-shift provides evidence to support the ‘big bang’ theory. The ‘big bang’ theory is one of the ways of explaining the ....................................... of the Universe. (1) (Total 4 marks) (a) The ‘Big Bang’ theory uses red-shift as evidence to explain the beginning of the Universe. Q25. How does the red-shift from distant galaxies provide evidence for the beginning of the Universe? ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (b) Cosmic microwave background radiation (CMBR) is a type of electromagnetic radiation. CMBR fills the Universe. It was first discovered in 1965 by two astronomers called Penzias and Wilson. (i) What do scientists believe is the origin of CMBR? ............................................................................................................... ............................................................................................................... (1) (ii) Why was the discovery of CMBR so important to the scientists believing the ‘Big Bang’ theory to be correct? ............................................................................................................... ............................................................................................................... (1) (iii) How is the wavelength of CMBR likely to change, if at all, over the next billion years? ............................................................................................................... Give a reason for your answer. ............................................................................................................... ............................................................................................................... (2) (Total 7 marks) Q26. A school is near a busy road. A car travels past the school at high speed. Photograph supplied by Design Pics/Thinkstock The students notice that the sound of the car engine seems to change as the car travels past the school. A teacher says that this is an example of the Doppler effect. The students decide to study the sound they hear from passing cars. (a) (i) Give one risk the students should consider when doing their study. ............................................................................................................... (1) (ii) As a car travels towards the students, the frequency of the sound the students hear is different to the frequency of the sound they would hear if the car was stationary. Draw a ring around the correct answer in the box to complete the sentence. decreased. Compared to the sound from the stationary car, the frequency has increased. become quieter. (1) (b) In the same way as the sound from the car engine changes, the light from most galaxies also seems to have a change in observed frequency. This is called red-shift. (i) The diagram shows four galaxies, P, Q, R and S. The arrows show the direction the galaxies are moving relative to the Earth. Which one of the galaxies is moving the fastest? Write the correct answer in the box. Which one of the galaxies will produce the biggest red-shift? Write the correct answer in the box. (2) (ii) Most scientists support a theory that the Universe began from a very small initial point. Red-shift can be used as evidence for this theory. What name is given to the theory that the Universe began from a very small initial point? ........................................................................................................................ (1) (iii) Cosmic microwave background radiation (CMBR) provides more evidence for this theory. CMBR is detected coming from space. Where does CMBR come from? Tick ( ) one box. CMBR only comes from near the Sun. CMBR comes from all parts of the Universe. CMBR only comes from the Moon. (1) (iv) Which statement gives the reason why most scientists support the theory that the Universe began from a very small initial point? Tick ( ) one box. The evidence proves it happened. There is no other way of explaining how the Universe began. At the moment it is the best way of explaining our scientific knowledge. (1) (Total 7 marks) The ‘big bang’ theory is one theory explaining the origin of the Universe. Q27. (a) The graphs X, Y and Z, show how the size of the Universe may have changed with time. Which graph would the ‘big bang’ theory suggest is correct? Write your answer, X, Y or Z, in the box. Explain the reason for your answer. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (b) In 1948, an alternative to the ‘big bang’ theory, called the ‘steady state’ theory, was developed. The ‘steady state’ theory suggested that the Universe, although expanding, has always existed without a beginning in time. (i) Complete the following sentence by drawing a ring around the correct line in the box. The measurement of red-shift in the light from distant galaxies provides evidence only the ‘big bang’ theory. to support only the ‘steady state’ theory. both the ‘big bang’ and ‘steady state’ theories. (1) (ii) In 1965, scientists rejected the ‘steady stat’ theory in favour of the ‘big bang’ theory. Suggest what might cause scientists to stop supporting one theory and to start supporting an alternative theory. ............................................................................................................... ............................................................................................................... ............................................................................................................... (1) (Total 5 marks) Q28. The diagram shows a teacher using a loudspeaker to demonstrate the Doppler effect. The loudspeaker, which produces a note of constant frequency, is swung around in a circle. (a) What is the Doppler effect? ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (2) (b) This demonstration of the Doppler effect can be used as a model for the red-shiftobserved in the light spectra from distant galaxies. What is red-shift and what does the size of the red-shift tell us about distant galaxies? ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (Total 5 marks) Q29.The diagram shows part of the lifecycle of a very large star. Use words or phrases from the box to complete the sentences contained in the diagram. black hole red supergiant supernova white dwarf (3) The star is stable. The star expands forming a ................................... . The star collapses, the outer layers explode as a ................................... . The centre collapses further and further until it finally forms a ................................... . (Total 3 marks) Q30.The diagram shows a teacher using a loudspeaker to demonstrate an important effect.The loudspeaker produces a note of constant frequency and is swung around in a circle. (a) As the loudspeaker moves towards the students, the frequency of the note heard by the students increases. What happens to the note heard by the students as the loudspeaker moves away from them? ........................................................................................................................ ........................................................................................................................ (1) (b) The teacher is using the demonstration to model the red-shift in light observed from most distant galaxies. (i) Which part of the demonstration: represents a moving galaxy? ............................................................................................................... is like the red-shift? ............................................................................................................... (2) (ii) Which one of the following statements gives the main reason why models are used in science? Put a tick ( ) in the box next to your answer. Models can help to explain an effect or theory. Models can prove that a theory is correct. Models can prove that a theory is wrong. (1) (c) Red-shift provides evidence to support the theory that the Universe began from a very small initial point. What name is given to this theory? ........................................................................................................................ (1) (Total 5 marks) Q31.Galaxies emit all types of electromagnetic wave. (a) (i) Which type of electromagnetic wave has the shortest wavelength? ............................................................................................................... (1) (ii) State one difference between an ultraviolet wave and a visible light wave. ............................................................................................................... ............................................................................................................... (1) (b) Electromagnetic waves travel through space at a speed of 3.0 x 108 m/s. The radio waves emitted from a distant galaxy have a wavelength of 25 metres. Calculate the frequency of the radio waves emitted from the galaxy and give the unit. Use the correct equation from the Physics Equations Sheet. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ Frequency = ...................................................................... (3) (c) Scientists use a radio telescope to measure the wavelength of the radio waves emitted from the galaxy in part (b) as the waves reach the Earth. The scientists measure the wavelength as 25.2 metres. The effect causing this observed increase in wavelength is called red-shift. (i) The waves emitted from most galaxies show red-shift. What does red-shift tell scientists about the direction most galaxies are moving? ............................................................................................................... ............................................................................................................... (1) (ii) The size of the red-shift is not the same for all galaxies. What information can scientists find out about a galaxy when they measure the size of the red-shift the galaxy produces? ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (iii) What does the observation of red-shift suggest is happening to the Universe? ............................................................................................................... ............................................................................................................... (1) (Total 9 marks) Q32.(a) Scientists have observed that the wavelengths of the light from galaxies moving away from the Earth are longer than expected. (i) What name is given to this observation? ............................................................................................................... (1) (ii) Draw a ring around the correct answer to complete each sentence. light can be stretched. This observation gives scientists evidence that galaxies are changing colour. the Universe is expanding. (1) (iii) There is a pattern linking the size of the observed increase in the wavelengths of light from a galaxy and the distance the galaxy is from the Earth. Which one of the graphs, L, M or N, shows the correct pattern? Write the correct answer in the box. (1) (b) Observations help scientists answer questions about the Universe. Scientists cannot answer every question. Which one of the following questions cannot be answered by scientists? Tick ( ) one box. How old is the Universe? Why was the Universe created? How fast does light travel through the Universe? (1) (Total 4 marks) Q33.(a) Observation of the spectra from distant galaxies provides evidence to support the ‘Big Bang’ theory. (i) Complete the following sentence. Many scientists think that the ‘Big Bang’ theory describes the ............ ............................................................................................................... (1) (ii) Tick ( ) one box to complete the sentence. The discovery of cosmic microwave background radiation was important because it ... proved the ‘Big Bang’ theory to be correct. provided more evidence to support the ‘Big Bang’ theory. proved the Universe will continue to expand forever. (1) (b) Many stars are part of a binary star system. Binary star systems have two stars. The visible spectrum from stars includes dark lines. These lines are at specific wavelengths. The diagram shows the position of two dark lines in the spectrum from the Sun. It also shows the same lines in the spectra from two stars A and B in a binary star system at the same point in time. (i) What name is given to the effect shown in the spectrum from star A? ............................................................................................................... (1) (ii) Scientists have concluded that the two stars in a binary star system orbit around a fixed point between the two stars. A comparison of the spectra from the two stars in a binary star system provides evidence to support this conclusion. Explain how. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (3) (Total 6 marks) Q34.(a) A lorry has an air horn. The air horn produces sound waves in the air. (i) Use one word to complete the following sentence. Sound waves cause air particles to ................................................................. . (1) (ii) The air horn produces sound waves at a constant frequency of 420 Hz. The wavelength of the sound waves is 0.80 m. Calculate the speed of the sound waves. Use the correct equation from the Physics Equations Sheet. ............................................................................................................... ............................................................................................................... ............................................................................................................... Speed = .......................................................... m/s (2) (b) A person standing at the side of the road, as the lorry goes past, hears the sound from the air horn change pitch. (i) What determines the pitch of a sound? Draw a ring around the correct answer. amplitude frequency loudness (1) (ii) As the lorry moves away from the person, the air horn continues to produce sound waves with a wavelength of 0.80 m. What is the wavelength of the sound waves the person heard? Draw a ring around the correct answer. shorter than 0.8 m equal to 0.8 m longer than 0.8 m (1) (iii) The sound waves the person heard from the moving air horn are different to the sound waves the air horn produced. What name is given to this effect? Draw a ring around the correct answer. diffraction Doppler refraction (1) (Total 6 marks) Q35.A teacher demonstrates the production of circular waves in a ripple tank. Diagram 1 shows the waves at an instant in time. Diagram 1 (a) Show on Diagram 1 the wavelength of the waves. (1) (b) The teacher moves the source of the waves across the ripple tank. Diagram 2 shows the waves at an instant in time. Diagram 2 (Actual size) (i) Use the correct answer from the box to complete each sentence. decreased increased stayed the same In Diagram 2, the observed wavelength of the waves at X has ...................................................................... . In Diagram 2, the frequency of the waves at X has ...................................................................... . (2) (ii) Take measurements from Diagram 2 to determine the wavelength of the waves received at X. Give the unit. ................................................................................................................ ................................................................................................................ Wavelength = ................................ (3) (c) The teacher uses the waves in the ripple tank to model the changes in the wavelengths of light observed from distant galaxies. When observed from the Earth, there is an increase in the wavelength of light from distant galaxies. (i) State the name of this effect. ................................................................................................................ (1) (ii) What does this increase in wavelength tell us about the movement of most galaxies? ................................................................................................................ ................................................................................................................ (1) (iii) Explain how this observation supports the Big Bang theory of the formation of the Universe. ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ (4) (iv) State one other piece of evidence that supports the Big Bang theory of the formation of the Universe. ................................................................................................................ ................................................................................................................ (1) (Total 13 marks) ## (NB. Answers referring to planets to gain zero marks Answers in terms of stars – deduct 1 mark) A light from (most) other galaxies shows a red-shiftB this means that these galaxies and our own galaxy are moving apart / Universe expandingC the red-shift of more distant galaxies is greaterD this means that the further apart galaxies are the faster they are moving away from each otherE the relationship is proportional so this means that in the past they all set out from the same point each properly related point for 1 mark [5] M2. (a) B answer includes items: D G each for 1 mark 3 (b) answer includes items: A E F [allow H here for a further mark] each for 1 mark 3 (c) answer includes items: C H* I J each for 1 mark [*unless already credited in (b)] 4 (d) ideas that: • lucky in the sense that they weren’t initially looking for the background radiation [others were!!!] • more than just lucky in that they investigated it and didn’t just ignore it each for 1 mark [NB Reference to letters only, not a prose answer, gain only ½ mark each. Total rounded down] 2 [12] M3. ideas that: galaxies show a red-shift gains 1 mark but more distant galaxies show bigger red-shift gains 2 marks galaxies moving away/Universe expanding gains 1 mark but more distant galaxies moving away faster gains 2 marks so all Universe once in one place for 1 further mark(only if the previous 2 marks are also gained) [5] M4. any four related points * the Universe (as we know it) started (about) 14 000/15 000 million years ago or (about) 15 billion years ago or between (about) 10 to 20 billion years ago * from one point or from a singularity or at the beginning of time * in an enormous outpouring of matter (and energy) * (and) has been expanding ever since * (evidence is that) the galaxies are all moving away from one another * (evidence is that) the more distant a galaxy is the faster it is moving away (from all the other galaxies) * evidence is microwave background or cosmic background radiation * ... relic of an earlier or hot phase resulting from (shortly) after the start or Big Bang * evidence is red shift * ... of light or radiation from (distant) stars or galaxies or quasars or due to Doppler (-Fizeau) effect accept bya for billion years ago or mya for million years ago do not credit vague responses such as it all started with a big explosion [4] M5. (a) 12.7 1 (b) the further away, the faster it is moving away 1 (c) all galaxies have been moving away from us for approximately the same length of time 1 therefore they were all probably produced at the same time 1 [4] M6. (a) any two from • Universe started in one place • (huge) explosion • Universe is expanding do not accept big bang 2 (b) Quality of written communication: Links needed between : galaxies, red shift, and distance / expansion 1 any two from • light from (galaxies) shifted towards red end of spectrum • the further away the galaxy, the greater the red shift • this shows that galaxies are moving away from us • this suggests that Universe is expanding do not accept light from planets 2 [5] M7. light from distant galaxies red shifted accept longer wavelength for red shifted 1 further galaxies display greater red shift 1 the further away galaxies are the faster they are moving away from us (our galaxy) 1 [3] M8. (i) the Universe might have started with an explosion/”Big Bang” 1 (ii) light from galaxies is shifted to red end of spectrum the further away the greater the red shift all galaxies receding furthest fastest microwave background echo of big bang for 1 mark each 2 [3] M9. light from (distant) galaxies shows shift to red end of spectrum wavelength increased explained by galaxies moving away from us more distant galaxies have greater recession speed seen in all directions suggests universe is expanding any sensible reference to similar effect on Earth any 6 for 1 mark each [6] M10. (i) an innumerable collection of galaxies accept any word meaning a large number for innumerable accept all the galaxies do not accept everything 1 (ii) all matter concentrated at a (single) point accept all matter part of a single ‘superatom’ 1 single (massive) explosion (sending matter outwards) 1 (iii) increasing or expanding 1 [4] M11. (i) an enormous explosion causing matter to spread from one point 1 (ii) it is increasing or expanding 1 [2] M12. (a) longer wavelength waves or light moved towards red end of spectrum 1 (galaxy) moving away from the Earth or space is expanding or the galaxy and Earth are moving apart accept us for Earth do not accept galaxies expanding 1 (b) big bang 1 [3] M13. (a) wavelength increases accept the crests are further apart ignore waves are further apart 1 frequency decreases accept pitch decreases ignore references to amplitude 1 (b) stars / galaxies / sources emit all / different types of electromagnetic waves / radiation accept two or more named electromagnetic waves accept answers in terms of frequencies / wavelengths 1 (c) (i) wavelength (of light) increases accept frequency decreases or light moves to red end of spectrum accept redder but do not accept red alone 1 (ii) it is the star (detected) furthest from theEarth accept galaxy for stars or it is moving away the fastest ignore reference to universe expanding 1 (d) (i) all matter compressed to / starts at / comes from a single point do not accept increasing gravitational pull accept everything / the universe for all matter 1 (massive) explosion sends matter outwards accept explosion causes universe to expand ignore explosion creates the universe or further reference to star / Earth formation 1 (ii) check validity / reliability of the evidence or change the theory to match the new evidence accept comparison of new and old evidence 1 [8] M14. (a) line shifts towards red end of spectrum do not accept reference to ‘red light’ do not accept ‘red shift’ as a stand alone response 1 wavelength (appears) to increase 1 galaxy is moving away (from the Earth) do not accept universe expanding or galaxy moving away from initial point do not accept planet on its own 1 (b) (i) light from A has a greater red shift accept light from A is more red do not accept reference to blue light 1 (ii) 3600 (million light years) allow 1 mark for showing that the linecould be extended or allow 1 mark for the correct use of a point on the line 2 [6] M15. (a) (i) red shift 1 accept Doppler effect (ii) the universe is expanding 1 (b) (i) big bang 1 (ii) at the moment it is the best way of explaining............ 1 [4] M16. (a) big bang theory – universe started at one point (then expanded) 1 steady state theory – universe has no origin / has always existed accept an answer in terms of mass eg steady state theory mass is created 1 (b) (i) wavelength (of light) increases accept answers in terms of frequency decrease accept wavelength stretched but not wave stretched or wavelength / light moves to red end of spectrum do not accept galaxy moves to the red end of the spectrum do not accept light becomes red / redder 1 (ii) red-shift is evidence / supports idea of expanding universe accept prove for support 1 both theories use the idea / accept / explain why the universe is expanding 1 (c) to find evidence to support one or both theories accept prove for support accept to gain more knowledge about the universe or to find evidence to disprove one or both theories 1 (d) answer involves (religious) belief accept it cannot be tested or no / insufficient evidence 1 [7] M17.(a) Big Bang (theory) 1 (b) K is closer (to Earth) than L accept converse argument for L 1 K is moving away (from Earth) more slowly than L 1 therefore K’s red-shift will be smaller than L’s 1 (c) wavelength is decreased 1 frequency is increased 1 (d) nuclear fusion in stars 1 results in (light(er)) nuclei joining to form heavier / larger nuclei accept a specific example 1 [8] M18. (a) the observed wavelength of the dark line from the distantgalaxy has increased 1 therefore the distant galaxy must be moving away from the Earth 1 suggesting the Universe is expanding outwards from a smallinitial point 1 (b) existence of cosmic microwave background radiation accept existence of CMBR 1 [4] M19. (a) (i) red-shift 1 (ii) expanding 1 (b) C 1 it is furthest from the Earth or it is furthest away or it has the largest red-shift or it is moving (away) the fastest only score if C is chosen 1 [4] M20. (a) wavelength (of light appears to) increase accept frequency (appears to) decrease accept light moves to the red end of the spectrum do not accept it moves to the red end of the spectrum do not accept light becomes redder 1 (b) (i) M is closer (to the Earth) than N 1 M is moving (away from the Earth) slower than N 1 (ii) 520 an answer between 510 and 530 inclusive gains 1 mark 2 (iii) more recent no mark for this but must be given to gain reason mark data more reliable accept data is more accurate or improved equipment / techniques more technology is insufficient or data obtained from more (distant) galaxies accept a wider range of data accept data closer to the line of best fit or data less scattered accept no anomalous result(s) accept all data fits the pattern 1 (c) wavelength is decreased 1 frequency is increased 1 [8] M21. (a) any one from: • above the atmosphere accept no atmospheric pollution • no clouds in the way • no light pollution answers in terms of being closer to space negate answers in terms of looking at the Earth negate 1 (b) (i) red-shift 1 (ii) expanding 1 (c) (i) as one gets bigger the other gets bigger accept (directly) proportional accept positive correlation 1 (ii) C 1 it is furthest from the Earth only scores if C is chosen or it is furthest away or has the largest red-shift or it is moving (away) the fastest 1 [6] M22. (a) (i) Universe began at a (very) small (initial) point ‘it’ refers to Universe 1 ‘explosion’ sent matter outwards or ‘explosion’ causing Universe to expand accept gas / dust for matter accept rapid expansion for explosion 1 (ii) light shows a red shift owtte the term red shift on its own does not score a mark 1 galaxies moving away (from the Earth) ‘it’ refers to light ‘they’ refers to galaxies accept star for galaxy do not accept planet for galaxy 1 (b) check reliability / validity of data accept check data accept collect more data 1 amend theory ordiscount the data accept replace old theory with new theory 1 (c) answer involves (religious) belief or no / insufficient evidence accept it cannot be tested 1 [7] M23. (a) frequency / pitch decreases accept wavelength increases accept it / the note becomes deeper / lower it / the note decreases is insufficient quieter is neutral 1 (b) (i) Models can help to explain an effect or theory. 1 (ii) (moving) loudspeaker represents the (moving) galaxy accept sound waves represent light waves 1 the decrease in frequency of the sound is like red-shift accept increase in frequency is like blue-shift accept answers in terms of wavelength change accept sound going away from you is like red-shift accept red-shift happens when galaxies / stars move away (from Earth) this accept only scores if first marking point scores 1 (c) big bang 1 [5] M24. (a) clearer / more detailed / sharper / less distorted image image is better is insufficient 1 ignore image is bigger any one from: • no light pollution accept no clouds to prevent observations • light is not scattered by the atmosphere accept air for atmosphereaccept (image) not distorted by the atmosphereaccept (light) does not have to pass through the atmospheredo not accept in terms of distance 1 (b) (i) bigger the red-shift, further the galaxy is from the Earth accept red-shift and distance are directly proportional accept there is a positive correlation 1 (ii) origin / start / beginning / creation accept expansion 1 [4] M25. (a) any three from: • red-shift shows galaxies are moving away (from each other / the Earth) • more distant galaxies show bigger red-shift or more distant galaxies show a greater increase in wavelength accept correct reference to frequency in place of wavelength • (in all directions) more distant galaxies are moving away faster accept (suggests) universe is expanding • suggests single point of origin (of the universe) 3 (b) (i) (radiation produced shortly after) ‘Big Bang’ accept beginning of time / beginning of the universe for ‘Big Bang’ 1 (ii) any one from: • can only be explained by ‘Big Bang’ • existence predicted by ‘Big Bang’ • provides (further) evidence for ‘Big Bang’ ignore proves ‘Big Bang’ (theory) ignore reference to red-shift 1 (iii) increase accept becomes radio waves 1 universe continues to accelerate outwards accept as universe continues to expand or greater red-shift 1 [7] M26. (a) (i) any suitable risk eg being injured by a car accept a measure to reduce the risk eg stand well away from edge of pavement stay on school grounds / don’t go onto the street be aware of the dangers of traffic car travelling at high speed is insufficient 1 (ii) increased 1 (b) (i) S 1 S 1 (ii) big bang (theory) 1 (iii) CMBR comes from all parts of the Universe 1 (iv) At the moment it is the best way of explaining our scientific knowledge 1 [7] M27. (a) Y accept cannot be X as size is increasing 1 shows Universe expanding this scores if Y or Z is chosen accept exploding outwards 1 from a (very small) point this only scores if Y is chosen accept from zero (size) answers in terms of planets negate the last two mark points 1 (b) (i) both the ‘big bang’ and ‘steady state’ theories 1 (ii) (new) evidence that supports / disproves a theory accept proves for supports or (new) evidence not supported by current theory accept there may be more evidence supporting one (theory) than the other (theory) accept new evidence specific to this question eg measurement of CBR or some types of star only found in distant parts of Universe (steady state suggests should be same throughout Universe) 1 [5] M28. (a) change in (observed) wavelength / frequency accept specific change eg increase accept pitch for frequency provided the source is sound 1 when source of waves / observer moves (relative to each other) accept specific example of source accept specific example of movement for both marks a specific change in wavelength / frequency must be linked to a correct specific movement of source / observer 1 (b) (observed) increase in wavelength of light (from distant galaxies) accept a correct description eg wavelength(s) of light (from distant galaxies) moves towards red end of spectrum or (observed) decrease in the frequency of light (from distant galaxies) (pattern) of (black) lines in (visible) spectrum move towards red end galaxy looks red negates this first mark point 1 because the galaxy is moving away from the Earth / us 1 the bigger the red-shift the faster the galaxy is moving accept bigger the red-shift the further the galaxy is from the Earth 1 [5] M29.red supergiant do not accept red giant 1 supernova 1 black hole 1 [3] M30.(a) frequency / pitch decreases accept wavelength increases accept it / the note becomes deeper / lower it / the note decreases is insufficient quieter is neutral 1 (b) (i) (moving) loudspeaker 1 change in sound as loudspeaker moves away 1 (ii) models can help to explain an effect or theory 1 (c) big bang 1 [5] M31.(a) (i) gamma accept correct symbol 1 (ii) any one from: • (ultraviolet has a) higher frequency ultraviolet cannot be seen is insufficient • (ultraviolet has a) greater energy • (ultraviolet has a) shorter wavelength ignore ultraviolet causes cancer etc 1 (b) 1.2 × 107 / 12 000 000 allow 1 mark for correct substitution, ie 3 × 108 = f × 25 2 hertz / Hz / kHz / MHz do not accept hz or HZ answers 12 000 kHz or 12 MHz gain 3 marks for full credit the numerical answer and unit must be consistent 1 (c) (i) away (from each other) accept away (from the Earth) accept receding 1 (ii) distance (from the Earth) accept how far away (it is) 1 speed galaxy is moving 1 (iii) (Universe is) expanding 1 [9] M32.(a) (i) red-shift accept Doppler (effect) 1 (ii) the Universe is expanding 1 (iii) N 1 (b) Why was the Universe created? 1 [4] M33.(a) (i) origin of the Universe accept (why) the Universe is expanding do not accept origin of the Earth 1 (ii) provided more evidence to support the ‘Big Bang’ theory 1 (b) (i) red-shift accept Doppler (shift) 1 (ii) (at the point in time shown the observed spectrum from) star A (shows it) is moving away from the Earth accept star A is moving away star A shows red-shift is insufficient 1 light from star B shows a decrease in wavelength accept light from star B shows blue-shift accept light from star B shows an increase in frequency 1 so star B is moving towards Earth 1 [6] M34.(a) (i) vibrate / oscillate accept a correct description move is insufficient 1 (ii) 336 allow 1 mark for correct substitution, ie 420 × 0.8(0) provided no subsequent step shown 2 (b) (i) frequency 1 (ii) longer than 0.8m 1 (iii) Doppler 1 [6] M35.(a) wavelength correctly shown 1 (b) (i) increased 1 decreased 1 (ii) 17-18 inclusive 1 evidence of measurement divided by 3 or mean of 3 separate measurements 1 mm accept cm if consistent with answer 1 (c) (i) red shift 1 (ii) moving away 1 (iii) the furthest galaxies show the biggest red shift 1 (meaning that) the furthest galaxies are moving fastest 1 (so the) Universe is expanding 1 (extrapolating backwards this suggests that) the Universe started from an initial point 1 (iv) cosmic microwave background radiation allow CMBR 1 [13] E2. This question proved to be more difficult even for the most able candidates than this type of question normally does. Better candidates did refer to a radiation profile in part (a) and went on to point out that the frequency at which most energy was radiated gave an indication of temperature. In part (b), candidates rarely distinguished between the microwave radiation from particular stars and galaxies (which Penzias and Wilon wanted to study) and the microwave noise from everywhere (which got in the way). In part (c) candidates often responded in terms of red-shift evidence for an expanding Universe rather than a match between the temperature of the cosmic microwave background radiation and the temperature the radiation from the time of the “big bang” is now likely to be. Nor were the ripples in cosmic microwave background radiation very often related to the need for some unevenness so that galaxies could form. In part (d) answers which combined the lucky aspect (they weren’t looking for the microwave noise) and the good science (having found it they studied it carefully) were very infrequent. Most candidates appear to have had sufficient time to complete the paper; in only a tiny minority of scripts was the final question left altogether unanswered or apparently answered very hurriedly. E3. Many weaker candidates produced answers relating to the origin of the solar system or of individual stars. Amongst creditworthy responses, the expansion of the Universe as indicated by galaxies moving away from each other was frequently mentioned but the fact that the speed of this movement increases with distance was mentioned much less frequently. It is the latter, proportional, relationship which implies that all the galaxies were once all at the same point. Some candidates correctly described observations of red-shifts as evidence for the above. In some scripts, however, the word “red-shift” was used in a way that indicated no understanding of the concept or of its significance. E4. Some candidates got marks in this question for stating that the Universe started at a point and is still expanding. Many answers gave further credence to the chaos theory by their presentations. A very small minority gave excellent answers. E5. (a) This part of the question was well answered. (b) This part was well answered. (c) Very few candidates scored two marks, due to not reading the question carefully. Few realised that they had to pick out the similarity in the times that the galaxies have been travelling away from us and relate this to the possibility that they were all produced at thesame time.Most merely gave descriptions of the ‘big bang’ theory and red shift. E6. (a) Few candidates were able to answer in simple terms of the Universe starting in one place with a big explosion and expanding ever since. The majority confused the question with the origin of our solar system and so failed to score. (b) To score the mark for Quality of Written Communication, candidates had to link the ideas of galaxies moving away from us / each other shown by light shifting to the red end of their spectrum and the bigger the shift the greater the distance from us. Only the most able scored all three marks on this question. It was clear that many candidates had no knowledge of this part of the specification. E7. Again it was shown that only the best candidates understood the concept of red shift. Weaker candidates made no reference to light in their explanations and frequently answered in terms of planets. It was rare to see an answer which explained how red shift provides evidence for an expanding Universe in terms of speed. Most candidates merely stated that ‘galaxies are moving away and this shows expansion’. E8. Most got the mark for the “big bang” in part (i). In part (ii) the better candidates gained both marks but many candidates produced answers which were vague. Red shift was mentioned frequently but not always in a context which related it to an expanding universe. References to planets were not uncommon and in the eyes of some candidates the “big bang” originated within the Solar System. E9. Some precise answers scored all the marks. However many candidates, who had the essential idea correct, wrote prose which suggested they were confused as to how the red shift has lead to the ‘big-bang’ theory. Vague ideas as to light shifting to the red end of the spectrum, and the effect increasing with distance and velocity were common. Few argued along the lines that the red-shift could be seen in all directions and that it increased with distance and that therefore the universe must be expanding. A very small number of candidates introduced the Doppler effect into their answers to score a mark. E10. Part (i) often gave rise to vague answers such as ‘everything’. Parts (ii) and (iii) were generally correct. E11. The quality of the answers given varied enormously. Some were excellent, whilst others bore more resemblance to the science fiction imagination of a 16 year old. E12. (a) Many candidates could recall that red shift was evidence for an expanding universe or for galaxies moving away, but only a few appeared to understand what ‘red-shift’ actually was. A common misconception was ‘galaxies appearing red’. The Doppler effect was mentioned fairly frequently and some candidates referred to sirens. (b) E13. Virtually all candidates could successfully name the ‘Big Bang Theory’. Part (a) was generally well answered. The link between increasing wavelength and decreasing frequency was usually correctly identified. Some candidates referred to amplitude correctly, although irrelevant to the question. Part (b) was poorly answered. Those candidates who had the right idea could often not express themselves clearly enough to gain credit. Many candidates were thinking about sending signals rather than receiving them. Part (c) was poorly answered. In part (c)(i) many candidates failed to gain credit because they answered in terms of what the red shift tells us rather than what it is. Some candidates with the correct idea referred to the star or galaxy moving to the red end of the spectrum, rather than the radiation. In part (c)(ii) many candidates did not gain credit because they gave a generalised answer about red-shift rather than the red shift of the particular star in the question. Although there were some good answers to part (d)(i) there were also many misconceptions, e.g. confusing the big bang with supernovas or with the creation of the Earth and the creation of life on Earth. Some candidates understand the big bang as an interim stage; ‘all the galaxies came together and exploded’. Whilst a number of candidates talked of matter being created by the explosion. In part (d)(ii) many candidates understood the need the check the reliability of the evidence. E14. Many answers to part (a) suggested rote learning with no understanding of the process. Answers included the galaxy moving towards the red end of the spectrum and the galaxies looking red. A significant number of candidates used stars, planets and galaxies interchangeably. In part (b)(i) many answers quoted speeds from the graphs and talked about galaxies rather than the spectra. Part (b)(ii) was answered well with most candidates scoring full credit. E15. Recall of cosmic phenomena was good in parts (a)(ii) and (b)(i), but recall of the term ‘red shift’ was poor. E16. (a) On the whole this question was well answered, but a significant number of candidates answered in terms of the Big Bang being the creation of the Earth, rather than the Universe. However a significant number of candidates failed to use the information given to answer the question. (b) (i) This was poorly answered. Imprecise use of language resulted in many answers along the lines of the galaxies themselves moving to the red end of the spectrum. (ii) As with part (a) a significant number of candidates confused the Earth for the Universe or completely ignored the information given about the ‘steady state’ theory. (c) Generally answered satisfactorily. (d) A pleasing number of candidates identified the key idea of the impossibility of finding evidence. However a common incorrect response was to say that the reason the question could not be answered was because nobody was there to see the creation. (a) Only two fifths of candidates were able to give the meaning of ‘red-shift’. A common incorrect answer was to refer to galaxies moving towards the red end of the spectrum. E20. (b) (c) E21. (i) Whilst this question was quite well answered, a significant number of marks were lost by candidates contradicting themselves, eg ‘M is moving slower than M’, an error which could be avoided if candidates were to read through their response. Quite a few answers explained what information could be gathered from red-shift data, but did not refer to the two galaxies mentioned. (ii) It was obvious that many candidates had not read the question carefully and as a consequence did not know that the gradient of a line needed to be calculated. Of those who did, many candidates counted squares up and across, rather than using values taken from the axes. When values were taken, common mistakes were not reading the values correctly or performing an incorrect calculation. (iii) Just under two thirds of candidates answered this correctly. However, a significant number of candidates think that in the 80 years between the two data sets, the universe will have expanded considerably so that the initial value would be more accurate. This part was generally well answered by most candidates, although references to wavelength being .squashed. and frequencies being ‘longer’ were not uncommon. (a) In spite of the fact that this question is frequently asked, the majority of candidates failed to obtain the mark. The most common answer was to say that the stars are so much closer if the telescope is mounted on a satellite. Several candidates stated that the telescopes would have a better view of the Earth if they were mounted on a satellite. These candidates had clearly not read the first line of the question, which told them that ‘scientists use telescopes to observe stars and galaxies’. (b) (i) Most candidates realised that the observation is known as red-shift. (ii) Most candidates realised that observation of red-shift gives evidence for the idea that the universe is expanding. (c) E22. (i) Most of the better candidates could state that as the distance increased, the speed increased, although few used terms such as ‘proportional’. Many of the weaker candidates stated that the speed and the distance were always equal to each other. (ii) About half of the candidates correctly identified galaxy C as being the galaxy from which the wavelength would have changed the most, with about two fifths of candidates being able to supply a correct reason. (a) (ii) Many candidates referred to red shift, although quite a few seemed to think that the galaxies themselves undergo red shift or that the galaxies were turning red. (b) There seemed to be some confusion between the terms ‘theory’ and ‘dat’, with a large number of candidates reading the question as a new theory having been stated. (c) Just over half of the candidates scored the mark with references either to the fact that there is no evidence or the question being a matter of philosophical or religious beliefs. E23. (a) The better candidates were able to respond correctly to this question in terms of frequency change. Many other candidates simply referred to a possible change in loudness. (b) (c) E24. (i) Considering the regularity of this or a similar question it seems surprising that over half of the candidates scored zero. Many of these candidates just refer to the creation of the earth or the solar system. (i) Just over two-thirds of candidates obtained the correct answer to this question. (ii) There were very few correct answers to this question. Many candidates did not offer an answer at all, and of those who did the majority of candidates clearly did not understand what they were being asked. The majority of candidates correctly identified this as the big bang theory. (a) Whilst three quarters of students were able to state that the image would be clearer, only about half were able to give a correct reason. A common incorrect response was to state that the satellite was nearer to the galaxies it was observing. (b) E25. (i) A number of students merely re-stated the question by saying that red-shift gives an indication of distance, without stating a relationship. (ii) The majority of students answered this correctly. (a) This was not well answered with just over a tenth of students scoring all three marks. Just over a quarter of students scored two out of the three marks, usually for indicating that red-shift shows that galaxies are moving away from each other or from the Earth and for the statement that the Universe is expanding. Common errors were that the Earth is expanding or that planets are moving away from each other. Also 'galaxies moving towards the red end of the spectrum' was often seen. (b) E26. (i) About two-thirds of students could give the origin of CMBR to score this mark. (ii) Only a third of students scored this mark. A lot of responses were claiming that CMBR was proof of the Big Bang theory. (iii) About two-thirds of students were able to state that the wavelength would be likely to increase, with about half of these students going on to give a correct reason. (a) Almost two-thirds of students could provide a sensible risk that should be considered, although some were more concerned about protecting the students' hearing rather than anything else. Some students thought they were being asked for a control measure, and were describing how the students could make it a fair test. (ii) (b) (i) Just over two-thirds of students realised that the frequency would increase as the car travelled towards them. Most students scored at least one of the two marks for this question but only a fifth scored both marks. (ii) The great majority of students knew of the Big Bang theory. (iii) About two-thirds of students scored this mark. (iv) Jst over half of students scored this mark. (a) Most students gained some credit here, mostly by correctly identifying ‘Y’ as the correct graph. Many students then went on to write that this graph showed the Universe expanding but fewer were able to state that the Universe had started at a point. A significant number of students confused the Universe with the Solar System or the Earth, and therefore could only score the first mark. E27. (b) E28. (i) Only a minority of students thought that red-shift provides evidence for both the ‘big bang’ and ‘steady state’ theories. (ii) Those students that scored the mark in this question tended to answer in terms of ‘one theory having more evidence that the other’. The question was a general one about the support of the scientific community for a particular theory and those that answered in these terms tended to be more successful than those who attempted to discuss the evidence for the ‘big bang’ and ‘steady state’ theories in particular. (a) The majority of students scored at least one mark. The most common error was simply to refer to ‘object / something’ moving towards an observer without any reference to a wave source. Many students scored one mark for changing frequency / wavelength. (b) Clearly, many students still do not understand what is meant by red shift. There are still many answers in terms of galaxies looking red or galaxies moving towards the red end of the spectrum. Answers often referred to planets or also talked about blue shift. The better students did score two or three marks, being able to describe red shift and relate it to at least one relevant point about distant galaxies. E29.The majority of students achieved 2 or 3 marks for this question. The main problem was that they did not see that the question referred to a 'very large star' which forms a black hole rather than a white dwarf. E30.(a) (b) The sound becoming quieter was a common incorrect response. No credit was given for 'it decreases' or 'the note decreases' since it was not clear enough to what the student referred. Correct answers were rare. (i) Most students realised that the moving loudspeaker represented the moving galaxy. However, the second mark was rarely gained. Responses such as 'the teacher' or 'the class' were the most common. Even those who identified the speaker moving away usually neglected to mention the change in the sound. (ii) (c) E31.(a) The majority of the students gained this mark. Apart from the odd suggestion such as 'evolution' or 'Doppler effect', the vast majority of students were able to answer this correctly. (i) (ii) Over half of students correctly identified gamma. There was a range of other responses, some of which were not electromagnetic waves, indeed some were not waves of any kind. Almost half of the students gave a correct answer. Common incorrect responses referred to uses of these waves. (b) Many students were able to identify the correct equation, and substitute numbers into it. Common errors were wrongly transposing the equation and attempting to convert 25 metres into cm or km. (c) (i) Over three-quarters of the responses were correct. (ii) Nearly two-thirds of students were able to identify at least one correct piece of information which can be obtained from the size of the red-shift. (iii) The vast majority of responses were correct. There are still a number of students who confuse the ‘Universe’ with ‘Earth’. E32.(a) (b) E33.(a) (b) (i) About half of the students knew that this observation is called red-shift. (ii) The great majority of students knew that the observation gives scientists evidence that the Universe is expanding. The most popular incorrect answer was that light can be stretched. (iii) Most students correctly identified graph N as representing the relationship between observed increase in wavelength and distance from Earth. Most students knew that the question “Why was the Universe created?” is one that scientists are unable to answer. The most popular wrong choice was “How fast does light travel through the Universe?” (i) Nearly two-thirds of students answered correctly. A common wrong answer was that the Big Bang theory describes the creation of Earth, or the Solar System. (ii) A majority of the students gave the correct answer. (i) ‘Red shift’ was correctly identified by most of students. A significant minority of students did not give an answer. (ii) One-sixth of students failed to attempt this question, whether through lack of time or because of its difficulty. A very small number scored all three marks, and a majority did not gain any marks. A common mistake was to say that red-shift and blue-shift indicated the distance of the star. A few candidates gave a good description of the redshift and blue-shift of a binary star system, but failed to relate it to Star A and Star B in the given diagram. E34.(a) (b) (i) About half of the students knew that sound waves cause the air particles to vibrate. A common answer that was insufficient to gain a mark was simply to say that sound waves caused the air particles to move. (ii) The majority of students could correctly complete the calculation to find the speed of the waves. The most common mistake was to divide 420 by 0.8 instead of multiplying. (i) Fewer than half of the students knew that it is the frequency that determines the pitch of a sound. The most common incorrect answer was “amplitude”. (ii) Fewer than half of the students knew that the wavelength would be longer than 0.8 m. (iii) Most students could identify the effect as being the Doppler effect.
