Download 9J. Higher Revision Questions.

9J. Higher Revision Questions.
Answer the questions in your book. Answer using as much detail as possible.
Forces.
1. What are the two ends of a magnet called?
2. What is a magnetic field?
3. What is the name of the force that pulls things towards the Earth?
4. The table shows the weight of a 1 kg mass on different planets and moons. On which body is
the weight of the 1 kg mass the largest?
5. Calculate the weight of a 5 kg mass on Earth.
Electromagnets.
6. In an experiment to investigate electromagnets, the number of turns on the coil are investigated
to see how this affects the strength of the electromagnet. Name one thing you need to keep the
same every time the electromagnet is tested. Explain why this needs to be kept the same.
7. The results are shown in the table below. How many paperclips did the electromagnet pick up
when it had 40 turns of wire?
8. What would be the conclusion for this investigation?
Circuits.
9. The diagram shows a circuit. What is the name for this type of circuit?
10. Draw an ammeter on the circuit that will measure the current flowing through the resistor.
11. Draw a voltmeter on the circuit that will measure the voltage across the resistor.
12. The resistor is changed for one with a higher resistance. Explain what will happen to the
current flowing through the resistor.
Static Electricity.
13. If you rub an acetate rod with a duster, the rod gets a positive charge. What charge does the
duster get?
14. Why do the rod and the duster both get the same amount of charge?
15. A rod made of a different material also gets a positive charge when rubbed with a duster.
What will happen to the two rods if they are put close to each other?
16. If you rub your hair with a balloon, some strands of hair stick out from your head. Use ideas
about static electricity to explain why this happens.
Resistance of a wire.
17. Two pieces of nichrome wire of the same length were used to measure the current at different
voltages. The results were plotted on a graph (shown below). Which piece of wire is the
thickest? Explain your answer.
18. Why was it important that both wires were the same length?
19. This graph shows the current and voltage through a light bulb. The light gets hotter and
brighter as the voltage across it is increased. Explain what the graph tells you about how the
resistance of the light changes with temperature.
Circuits.
20. A current of 0.4 A flows through a resistor. The voltage across the resistor is 8 V.
Calculate the resistance of the resistor using the formula below. Show your working out.
Electromagnets.
21. The diagram shows part of the magnetic field around an electromagnet, complete the diagram.
22. The size of the current is increased. How will this affect the magnetic field?
23. Describe how you can make an electromagnet stronger.
24. The diagrams show two ways in which a wire can be placed in a magnetic field. Explain which
of these arrangements will result in a force on the wire when a current flows through it.
25. Describe two ways in which the size of the force experienced by the wire could be increased.
Relay switches.
26. The diagram shows a relay. When current flows in the low current circuit the contacts close.
a. Explain why this happens.
b. How do relays improve safety?
Higher Answers.
1. North pole and South pole.
2. The space around a magnet where it can affect magnetic materials / other magnets.
3. Gravity
4. Earth
5. 5 × 10 N = 50 N
6. The current / voltage in the coil, or the same type of core in the electromagnet. Because it
could also affect the strength of the electromagnet / to make the test fair.
7. 13
8. The more turns of wire on the coil, the stronger the electromagnet.
9. Parallel
10. Ammeter drawn in any part of the lower branch (i.e. in the correct position to measure the
current through the resistor).
11. Voltmeter correctly drawn connected across the resistor.
12. It will go down / get less, because it is harder for current to flow if the resistance is higher.
13. Negative.
14. Electrons are transferred from one object to the other. The number of extra electrons/negative
charges on one object is the same as the number of unbalanced positive charges on the other.
15. They will repel each other.
16. Hair has a charge of static electricity (or electrons are transferred when the hair is rubbed
against the balloon). All the strands of hair have the same charge, so they repel each other.
17. B was the thickest wire- the line is steeper. Thicker wires have lower resistance.
18. They had to be the same length because he length of the wire also affects the resistance
19. The resistance does not change with temperature at low voltages / temperatures.
The resistance increases with increasing temperature above a certain voltage / temperature.
20. Resistance = 8 /0.4 = 20
21. Diagram completed showing the magnetic field symmetrically below the electromagnet
22. The field would be stronger
23. Add more coils.
24. B. The wire has to be at right angles/cut across the direction of the field.
25. Increase the size of the current, Increase the strength of the magnetic field
26 a The magnetic field from the coil of wire/electromagnet attracts the iron block and the metal
bar connects the contacts in the high-current circuit.
b A high current can be switched on without a person having to touch any part of the high-current
circuit.
9J. Standard Revision Questions.
Answer the questions in your book. Answer using as much detail as possible.
Forces.
1. What are the two ends of a magnet called?
2. What is a magnetic field?
3. What is the name of the force that pulls things towards the Earth?
4. The table shows the weight of a 1 kg mass on different planets and moons. On which body is
the weight of the 1 kg mass the largest?
5. Calculate the weight of a 5 kg mass on Earth.
Electromagnets.
6. In an experiment to investigate electromagnets, the number of turns on the coil are investigated
to see how this affects the strength of the electromagnet. Name one thing you need to keep the
same every time the electromagnet is tested. Explain why this needs to be kept the same.
7. The results are shown in the table below. How many paperclips did the electromagnet pick up
when it had 40 turns of wire?
8. What would be the conclusion for this investigation?
Circuits.
9. The diagram shows a circuit. What is the name for this type of circuit?
10. Draw an ammeter on the circuit that will measure the current flowing through the resistor.
11. Draw a voltmeter on the circuit that will measure the voltage across the resistor.
12. The resistor is changed for one with a higher resistance. Explain what will happen to the
current flowing through the resistor.
Static Electricity.
13. If you rub an acetate rod with a duster, the rod gets a positive charge. What charge does the
duster get?
14. Why do the rod and the duster both get the same amount of charge?
15. A rod made of a different material also gets a positive charge when rubbed with a duster.
What will happen to the two rods if they are put close to each other?
16. If you rub your hair with a balloon, some strands of hair stick out from your head. Use ideas
about static electricity to explain why this happens.
Resistance of a wire.
17. Two pieces of nichrome wire of the same length were used to measure the current at different
voltages. The results were plotted on a graph (shown below). Which piece of wire is the
thickest? Explain your answer.
18. Why was it important that both wires were the same length?
19. This graph shows the current and voltage through a light bulb. The light gets hotter and
brighter as the voltage across it is increased. Explain what the graph tells you about how the
resistance of the light changes with temperature.
Circuits.
20. A current of 0.4 A flows through a resistor. The voltage across the resistor is 8 V.
Calculate the resistance of the resistor using the formula below. Show your working out.
Electromagnets.
21. The diagram shows part of the magnetic field around an electromagnet, complete the diagram.
22. The size of the current is increased. How will this affect the magnetic field?
23. Describe how you can make an electromagnet stronger.
Standard Answers.
1. North pole and South pole.
2. The space around a magnet where it can affect magnetic materials / other magnets.
3. Gravity
4. Earth
5. 5 × 10 N = 50 N
6. The current / voltage in the coil, or the same type of core in the electromagnet. Because it
could also affect the strength of the electromagnet / to make the test fair.
7. 13
8. The more turns of wire on the coil, the stronger the electromagnet.
9. Parallel
10. Ammeter drawn in any part of the lower branch (i.e. in the correct position to measure the
current through the resistor).
11. Voltmeter correctly drawn connected across the resistor.
12. It will go down / get less, because it is harder for current to flow if the resistance is higher.
13. Negative.
14. Electrons are transferred from one object to the other. The number of extra electrons/negative
charges on one object is the same as the number of unbalanced positive charges on the other.
15. They will repel each other.
16. Hair has a charge of static electricity (or electrons are transferred when the hair is rubbed
against the balloon). All the strands of hair have the same charge, so they repel each other.
17. B was the thickest wire- the line is steeper. Thicker wires have lower resistance.
18. They had to be the same length because he length of the wire also affects the resistance
19. The resistance does not change with temperature at low voltages / temperatures.
The resistance increases with increasing temperature above a certain voltage / temperature.
20. Resistance = 8 /0.4 = 20
21. Diagram completed showing the magnetic field symmetrically below the electromagnet
22. The field would be stronger
23. Add more coils.