Download Homework Booklet - Lesmahagow High School

Prestwick Academy
Physics Department
Higher Homework
Relationships Required for Higher Physics
2
3
Homework 1 - Significant Figures, Prefixes & Scientific
Notation
1. In each of the following cases, the stated value has too many significant figures.
The appropriate number of significant figures is stated in brackets after the
quantity. Round each quantity to the correct number of significant figures.
a)
b)
c)
d)
11.85467 V
50.7835 Hz
0.000000712 m
2.998 x 108 ms-1
(3 significant figures)
(2 significant figures)
(3 significant figures)
(2 significant figures)
(2)
2. Calculate the following quantities from the information given, and report your
answer to an appropriate number of significant figures. Remember to give your
answer in scientific notation!
a) Calculate the frequency of microwaves that have a wavelength of
3.1 x 10-2 m, and are travelling at 3.0 x 108 ms-1.
b) Calculate the energy used if a 1.2 kW kettle takes 2 minutes to boil.
(2)
(2)
3. Copy the table below, and fill in all the blanks.
QUANTITY
Speed of light
Charge on an electron
Wavelength of red light
Voltage used in the
Super Grid
VALUE
SCIENTIFIC NOTATION
3 x 108 ms-1
0.000 000 000 000 000
000 160 C
7 x 10-7 m
250 000 V (to 3 sig figs)
(2)
4. Re-write the following quantities using the most appropriate prefix.
a) 0.000 006 m
b) 1 500 000 000 Hz
c) 3200 W
d) 0.008 g
e) 2.7 x 106 J
f) 7.42 x 10-7 m
(3)
Total marks: 11
4
Homework 2 - Uncertainties
a) The circuit shown is set up to determine the resistance of a resistor. In one
repetition of the experiment, the readings are as shown on the meters. The
experiment is repeated several times to allow mean values for both current and
voltage to be found.
0
1
2
3
V
0
0.
2
0.
4
0.
6
A
a) Give the ammeter and voltmeter readings and state the scale reading uncertainty
in each case.
(2)
b) Using Ohm’s Law (V = IR), calculate a value for the resistor. Estimate the absolute
uncertainty in the calculated value of the resistance and explain how you arrived at
your estimate.
(3)
c) The experiment is repeated 5 times, and the values recorded for the current are as
follows:
0.44 A; 0.43 A; 0.45 A; 0.42 A; 0.44 A
Calculate the mean current, and the random uncertainty in the mean.
(3)
2. A current is measured with an analogue meter which has scale divisions of 0.1 A,
and is found to be 5.4 A. The reading is double-checked with a digital meter, and
again is found to be 5.4 A. Using which instrument gives the larger scale reading
uncertainty? Explain your answer.
(2)
Total marks: 10
5
Homework 3 - Vectors
1. Explain the difference between a vector and a scalar quantity and give 2
examples of each.
(2)
2. A ferry crosses a river that is flowing at 5 ms-1.
If the ferry is travelling at 12 ms-1, calculate
its resultant velocity.
5 ms-1
(2)
12 ms-1
3. An aircraft pilot wishes to fly north at 800 km h-1. A wind is blowing at 80 km h-1
from west to east. What speed and course must he select in order to fly the
desired course?
(2)
4. A footballer runs around a football pitch as part of his training. He starts at the
halfway line (point X), and runs around the pitch to point D as shown. This run
takes him 50 seconds.
C
100 m
B
N
70 m
70 m
W
E
S
D
X
50 m
A
a) Calculate the total distance travelled by the footballer.
b) What is his final displacement at point D?
c) Calculate the footballer’s average velocity for the run.
(1)
(1)
(2)
Total marks: 10
6
Homework 4 - Equations Of Motion
1. A workman on scaffolding outside one of the physics classrooms drops
a wrench. A student times it as it falls past the 2m tall classroom window and
found that it took 0.6s to fall . Calculate the wrench’s initial velocity as it
appears at the top of the window.
(2)
2. A train decelerates from 12.0 ms-1 to 5.0 ms-1 while travelling a distance of
119.0 m along a straight track. Calculate the deceleration of the train.
(2)
3. A skier sets off from rest and accelerates uniformly down a straight ski run.
After 4·50 seconds she reaches a speed of 23·0 m s-1. After this time the skier
no longer accelerates but continues to travel at 23·0 m s-1 for a further 11·0 s.
Calculate:
a) the acceleration of the skier during the first 4·50 s of her run.
(2)
b) the total distance travelled by the skier.
(3)
4. In a handicap sprint race, sprinters P and Q both start the race at the same time
but from different starting positions on the track.
The handicapping is such that both sprinters reach XY, as shown below, at the
same time.
Sprinter P has a constant acceleration of 1.6 ms-2 from the start line to the line
XY. Sprinter Q has a constant acceleration of 1.2 ms-2 from the start line to XY.
a) Calculate the time taken by the sprinters to reach line XY.
b) Find the speed of each sprinter at this line.
c) What is the distance, in metres, between the starting lines for
sprinters P and Q?
(2)
(3)
(2)
Total marks: 16
7
Homework 5 - Forces
1. A train made up of 3 carriages is pulled along a level track by a force of 16 500 N.
Each of the carriages has a mass of 8 000 kg, and each experiences 1500 N of
resistive forces.
Force
applied by
the engine
B
A
a) Calculate the acceleration of the train.
b) Work out the tension in link B.
(2)
(2)
2. A rocket of mass 200 kg accelerates vertically upwards from the surface of a
planet at 2ms-2. The gravitational field strength on the planet is 4 Nkg-1.
What is the size of the force being supplied by the rocket’s engines?
(2)
3. The lift in a department store has a mass of 1100kg.
The lift is descending with a uniform downwards
acceleration of 2ms-2. The acceleration due to gravity
can be taken as 10ms-2.
What is the force applied to the lift by the lift cable?
(2)
4. A pupil pushes two blocks A and B with a 30 N force.
4kg
2kg
Ignoring friction,
a) calculate the acceleration of the blocks.
b) find the force A exerts on B.
(2)
(2)
Total marks: 12
8
Homework 6 – Force as a Vector
1. In the diagram below, calculate the component of the weight acting down the
slope. The mass of the trolley is 24 kg.
(2)
30o
2. A 2 kg trolley is placed on a 35o slope. The trolley accelerates down the slope and
a frictional force of 1.5 N acts up the slope.
1.5 N
35o
a) Calculate the acceleration of the trolley.
(3)
b) What effect does increasing the angle of slope have on acceleration? (1)
3. Two ropes are used to pull a boat at constant speed along a canal.
Each rope exerts a force of 150 N at 20o to the direction of travel of the boat as
shown.
a) Calculate the magnitude of the resultant force exerted by the ropes. (3)
b) What is the magnitude of the frictional forces acting on the boat?
(1)
Total marks: 10
9
Homework 7 – Conservation of Energy
1. A block of mass 3·0 kg is held at rest on a frictionless slope. The front edge of the
block is 0·80 m above the ground as shown in Figure 2.
a) Calculate the gravitational potential energy of the block when it is in the
position shown in Figure 2.
(2)
b) The block is released. Use conservation of energy to find the speed of the
block at the foot of the slope.
(3)
2. In an experiment to calculate the power developed , a 70 kg man runs up the
stairs as fast as he can. The flight of stairs is 4.30 m tall.
If it took the man 5.0 s to run up the stairs, calculate
his power.
(3)
3. A pendulum swings as shown in the diagram.
Points A and C are the extremities of the
swing of the pendulum. The mass of the
bob is 0.5 kg. Calculate:
a) the maximum potential energy of the bob.
b) the maximum kinetic energy of the bob.
c) the maximum speed of the bob.
20 cm
(2)
(2)
(2)
Total marks: 14
10
Homework 8 – Momentum and impulse
1. In a rugby match, a 110 kg forward in one team tackles
an 85 kg back in the other team. The forward is travelling
at 5 ms-1 and the back at 7 ms-1 in the opposite direction
when they collide and ‘stick’ together.
Take the direction of the forward as the positive direction.
a) Calculate the velocity of the pair immediately after the collision.
b) Show by calculation whether this collision is elastic or inelastic.
(2)
(2)
2. Explain, in terms of forces on the driver, why a seatbelt offers a far less damaging
alternative to a steering wheel when a car stops suddenly during a collision. (2)
3. In a game of squash, a ball of mass 0.1 kg is moving towards the
player with a velocity of 20 ms-1. She strikes it with the racquet
and it returns towards the wall at 40 ms-1. If the time of contact
between racquet and ball is 50 ms, calculate the force applied on
the ball by the racquet.
(2)
4. A golfer strikes a stationary golf ball, and the force applied by the club on the ball
varies as shown in the graph below. Use this graph to determine the final speed
of the golf ball. The ball’s mass is 0.1 kg.
(2)
Average
Force / N
Total marks: 10
160
120
80
40
0
20
40
60
80
Time of
contact / ms
11
Homework 9 - Gravitation
1. During a visit to the moon, the astronaut fires a small experimental projectile
across a level surface. The projectile is launched, from point P, at a speed of 24.0
ms-1 and at an angle of 60° to the horizontal.
The projectile lands 26.0 s later at point X.
a)
b)
Calculate the horizontal speed of the projectile at point P.
Calculate the horizontal distance from P to X.
(1)
(2)
2. A model rocket enthusiast launches a rocket from the edge of a cliff on a calm day
(no air resistance).
O
30O
A
B
The flight of the rocket from launch at point O to splashdown in the sea, at B,
takes 7 seconds.
a) The rocket is launched at an angle of 30O to the ground with velocity
40ms-1.
Show that the time it takes to go from point O to point A, which is level
with the cliff, is 41s.
(3)
b) Find the height of the cliff.
(3)
3. Calculate the gravitational force between two cars parked 0.50 m apart. The
mass of each car is 1000 kg.
(2)
Total marks: 11
12
Homework 10 – Special Relativity
1. A scientist in the laboratory measures the time taken for a nuclear reaction to
occur in an atom. When the atom is travelling at 8·0 × 107 m s 1 the reaction
takes 4·0 × 104 s. Calculate the time for the reaction to occur when the atom is
at rest.
(2)
2. The light beam from a lighthouse sweeps its beam of light around in a circle once
every 10 s. To an astronaut on a spacecraft moving towards the Earth, the beam
of light completes one complete circle every 14 s. Calculate the speed of the
spacecraft relative to the Earth.
(2)
3. A pi meson is moving at 0·90 c relative to a magnet. The magnet has a length of
2·00 m when at rest to the Earth. Calculate the length of the magnet in the
reference frame of the pi meson.
(2)
4. In the year 2050 a spacecraft flies over a base station on the Earth. The spacecraft
has a speed of 0·8 c. The length of the moving spacecraft is measured as 160 m
by a person on the Earth. The spacecraft later lands and the same person
measures the length of the now stationary spacecraft. Calculate the length of the
stationary spacecraft.
(2)
5. The star Alpha Centauri is 4·2 light years away from the Earth. A spacecraft is sent
from the Earth to Alpha Centauri. The distance travelled, as measured by the
spacecraft, is 3·6 light years.
a) Calculate the speed of the spacecraft relative to the Earth.
(2)
b) Calculate the time taken, in seconds, for the spacecraft to reach Alpha
Centauri as measured by an observer on the Earth.
(2)
c) Calculate the time taken, in seconds, for the spacecraft to reach Alpha
Centauri as measured by a clock on the spacecraft.
(2)
Total marks: 14
13
Homework 11 – Doppler Effect
1. In the following sentences the words represented by the letters A, B, C and D are
missing:
A moving source emits a sound with frequency fs. When the source is moving
towards a stationary observer, the observer hears a ____A_____ frequency fo.
When the source is moving away from a stationary observer, the observer hears a
____B_____ frequency fo. This is known as the _____C____ ____D_____.
Match each letter with the correct word from the list below:
Doppler
effect
higher
quieter
louder
lower
softer
(2)
2. A student is standing on a station platform. A train approaching the station
sounds its horn as it passes through the station. The train is travelling at a speed
of 25 m s 1. The horn has a frequency of 200 Hz.
a) Calculate the frequency heard as the train is approaching the student. (2)
b) Calculate the frequency heard as the train is moving away from the
student.
(2)
3. A man standing at the side of the road hears the horn of an approaching car. He
hears a frequency of 470 Hz. The horn on the car has a frequency of 450 Hz.
Calculate the speed of the car.
(2)
4. A source of sound emits a signal at 600 Hz. This is observed as 640 Hz by a
stationary observer as the source approaches.
Calculate the speed of the moving source.
(2)
5. A battery-operated siren emits a constant note of 2200 Hz. It is rotated in a circle
of radius 0·8 m at 3·0 revolutions per second. A stationary observer, standing
some distance away, listens to the note made by the siren.
a) Show that the siren has a constant speed of 15·1 m s 1.
b) Calculate the minimum frequency heard by the observer.
c) Calculate the maximum frequency heard by the observer.
(2)
(2)
(2)
Total marks: 16
14
Homework 12 – Redshift and Hubble’s Law
1. Light from a distant galaxy is found to contain the spectral lines of hydrogen. The
light causing one of these lines has a measured wavelength of 466 nm. When the
same line is observed from a hydrogen source on Earth it has a wavelength of 434
nm.
a) Calculate the Doppler shift, z, for this galaxy.
b) Calculate the speed at which the galaxy is moving relative to the
Earth.
c) In which direction, towards or away from the Earth, is the galaxy
moving?
(2)
(2)
(1)
2. The galaxy Corona Borealis is approximately 1 000 million light years away from
the Earth. Calculate the speed at which Corona Borealis is moving away from the
Earth.
(2)
3. A galaxy is moving away from the Earth at a speed of 3·0 × 107 m s 1. The
frequency of an emission line coming from the galaxy is measured. The light
forming the same emission line, from a source on Earth, is observed to have a
frequency of 5·00 × 1014 Hz.
a) Show that the wavelength of the light corresponding to the emission line
from the source on the Earth is 6·00 × 107 m.
(2)
b) Calculate the frequency of the light forming the emission line coming from
the galaxy.
(2)
4. A distant quasar is moving away from the Earth. Hydrogen lines are observed
coming from this quasar. One of these lines is measured to be 20 nm longer than
the same line, of wavelength 486 nm from a source on Earth.
a) Calculate the speed at which the quasar is moving away from the
Earth.
(2)
b) Calculate the approximate distance, in millions of light years, that the
quasar is from the Earth.
(2)
Total marks: 15
15
Homework 13 – AC Signals
1. The oscilloscope below shows the potential difference over a bulb attached to an
AC power supply.
The y-gain is set at 5V / div.
The time base is set at 5ms / div.
a) State the peak potential difference of the trace.
b) Calculate the frequency of the supply.
c) Calculate the rms value of the potential difference.
(1)
(2)
(2)
2. The root mean square voltage produced by a low voltage power supply is 10 V.
a) Calculate the peak voltage of the supply.
b) An oscilloscope, with its time-base switched off, is connected across
the supply. The Y-gain of the oscilloscope is set to 5 V cm–1. Describe
the trace seen on the oscilloscope screen.
(2)
(2)
3. An a.c. signal of frequency 20 Hz is connected to an oscilloscope. The time-base
switch on the oscilloscope is set at 0.01 s cm–1.
Calculate the distance between the neighbouring peaks of this waveform when
viewed on the screen.
(2)
Total marks: 11
16
Homework 14 – Emf & Internal Resistance
1. In the circuit below, the reading on the voltmeter is 5 V when switch S is open
and 3 V when it is closed.
S
V
15 W
a) What is the Emf of the cell?
(1)
b) Calculate the current flowing in the circuit when the switch is closed. (2)
c) What is the internal resistance of the cell?
(2)
2. The graph shows how the voltage across the terminals of a battery changes as the
current from the battery is varied.
a) Calculate the internal resistance of the battery.
b) What is the value of the current from the battery when it is shortcircuited?
(2)
(3)
Total marks: 10
17
Homework 15 - Capacitors
1. The circuit below is set up with the capacitor initially discharged. The switch is put
to position A, and the capacitor allowed to fully charge. This process takes 60
seconds.
6V
A
B
2000 mF
30 kW
50 kW
a) Calculate the initial charging current in the circuit.
(2)
b) State the current once the capacitor is fully charged.
(1)
c) Draw a graph of charging current Vs time. You should have values on both
axes.
(2)
d) What is the potential difference over the capacitor when it is fully
charged?
(1)
The switch is thrown to position B, and the capacitor is allowed to fully discharge.
e) Calculate the initial discharge current.
(2)
f) How would the discharge time compare to the charge time? Explain your
answer.
(2)
2. The charge stored by a 2 mF capacitor is 4 x 10-4 C.
a) How much energy was required to charge the capacitor?
b) What is the voltage across the capacitor?
(2)
(2)
Total marks: 14
18
Homework 16 – Conductors, Semiconductors and Insulators
1. Give examples of two conductors, two insulators and two semiconductors.
(3)
2. The conductivity of a semiconductor material can be increased by ‘doping’.
a) Explain what is meant by the ‘conductivity’ of a material.
b) Explain, giving an example, what is meant by ‘doping’ a
semiconductor.
c) Why does ‘doping’ decrease the resistance of a semiconductor
material?
(1)
(2)
(1)
3. A sample of pure germanium (four electrons in the outer shell) is doped with
phosphorus (five electrons in the outer shell). What kind of semiconductor is
formed?
(1)
4. Why does a sample of n-type semiconductor still have a neutral overall
charge?
(2)
5. Describe the movement of the majority charge carriers when a current flows in:
i.
ii.
an n-type semiconductor material
a p-type semiconductor material.
(1)
(1)
Total marks: 12
19
Homework17 – p-n Junctions
1. A p-n junction diode is connected across a d.c. supply as shown.
a) Is the diode connected in forward or reverse bias mode?
(1)
b) Describe the movement of the majority charge carriers across the p-n
junction.
(2)
c) What kind of charge is the only one that actually moves across the
junction?
(1)
2. When positive and negative charge carriers recombine at the junction of ordinary
diodes and LEDs, quanta of radiation are emitted from the junction.
a) Does the junction have to be forward biased or reverse biased for
radiation to be emitted?
b) What form does this emitted energy take when emitted by:
(i) an LED
(ii) an ordinary junction diode?
3. a) State two advantages of an LED over an ordinary filament lamp.
b) An LED is rated as follows:
operating p.d. 1·8 V, forward current 20 mA
(1)
(1)
(1)
(1)
The LED is to be operated from a 6 V d.c. power supply.
(i) Draw a diagram of the circuit, including a protective resistor, which allows the
LED to operate at its rated voltage.
(1)
(ii) Calculate the resistance of the protective resistor that allows the LED to
operate at its rated voltage.
(3)
Total marks: 12
20
Homework 18 – The Standard Model
1. Copy and complete the table by placing the fermions in the list below in the
correct column of the table.
bottom
charm
electron neutrino
tau
down
muon
tau neutrino
Quarks
electron
strange
muon neutrino
top
up
Leptons
(6)
2. a) State the difference between a hadron and a lepton in terms of the type of
force experienced by each particle.
(2)
b) Give one example of a hadron and one example of a lepton.
(1)
3. Information on the sign and charge relative to proton charge of six types of
quarks (and their corresponding antiquarks) is shown in the table.
Quark name
Charge relative
to size of proton
charge
Antiquark name
Charge relative
to size of proton
charge
up
+2/3
antiup
–2/3
charm
+2/3
anticharm
–2/3
top
+2/3
antitop
–2/3
down
–1/3
antidown
+1/3
strange
–1/3
antistrange
+1/3
bottom
–1/3
antibottom
+1/3
a) Calculate the charge of the following combinations of quarks:
i. two up quarks and one down quark
ii. one up quark and two down quarks
iii. two antiup quarks and one antidown quark
iv. one antiup quark and two antidown quarks.
(2)
b) Name the force which holds the quarks together in protons and neutrons. (1)
Total marks: 12
21
Homework 19 – Forces on Charged Particles
1. Draw the electric field around the following charges. You must show the direction
of the field clearly.
a)
+
-
b)
+
(3)
2. What is the definition of a volt?
(1)
3. Look at the following diagram.
1.5 C
300 V
100 V
a) What is the potential difference between the two plates?
b) Calculate the work done in moving the charged particle across the
electric field.
(1)
(2)
4. The diagram shows an arrangement which is used to accelerate electrons.
The potential difference between the cathode and anode is 2.5 kV.
Assuming the electrons start from rest, calculate the speed of the electron as it
reaches the anode.
(3)
Total marks: 10
22
Homework 20 – Particle Accelerators
In the following questions, when required, use the following data:
Charge on electron = –1·60 × 1019 C
Charge on proton = 1·60 × 1019 C
Mass of electron = 9·11 × 1031 kg
Mass of proton = 1·67 × 1027 kg
1. In an evacuated tube, an electron initially at rest is accelerated through a p.d. of
500 V.
a) Calculate, in joules, the amount of work done in accelerating the
electron.
b) How much kinetic energy has the electron gained?
c) Calculate the final speed of the electron.
(2)
(1)
(2)
2. In an electron gun, electrons in an evacuated tube are accelerated from rest
through a potential difference of 250 V.
a) Calculate the energy gained by an electron.
b) Calculate the final speed of the electron
(2)
(2)
3. The power output of an oscilloscope (cathode-ray tube) is estimated to be 30 W.
The potential difference between the cathode and the anode in the evacuated
tube is 15 kV.
a) Calculate the number of electrons striking the screen per second.
b) Calculate the speed of an electron just before it strikes the screen,
assuming that it starts from rest and that its mass remains constant.
(3)
(3)
Total marks: 15
23
Homework 21 – Fission and Fusion
1. There are three isotopes of hydrogen:
1
1H
a)
b)
2
1H
3
1H
How many protons does each nucleus have?
How many neutrons does each nucleus have?
(1)
(1)
2. Energy is produced within the Sun by fusion reactions.
a) State what is meant by a fusion reaction.
b) Explain briefly why a fusion reaction releases energy.
(1)
(2)
2. A nuclear reaction is described by the equation below:
a) What type of reaction is this?
(1)
b) Calculate the missing numbers X and Y.
(1)
c) Using information from the table below, calculate the energy released in
this reaction.
NUCLEUS/PARTICLE
MASS (U)
239Pu
239.0512
137Te
137.0000
yMo
1n
99.9066
1.0087
(3)
Total marks: 10
24
Homework 22 – Photoelectric Effect
1. When introducing the photoelectric effect a Physics teacher writes:
‘One of the important factors affecting photoelectric emission from a metal is the
threshold frequency for the metal.’
Explain the meaning of the terms:
a) photoelectric emission;
b) threshold frequency.
2. Red light has a wavelength of 6·44 × 107 m.
Calculate the energy of one photon of this light.
(1)
(1)
(3)
3. For a certain metal, the energy required to eject an electron from an atom is 3 x
10-19 J.
a) What is the minimum frequency of electromagnetic radiation required to
produce the photoelectric effect with this metal?
(2)
b) The metal is illuminated with blue light that has a wavelength of 400 nm.
Show by calculation that this will cause the photoelectric effect to
occur.
(2)
c) Calculate the kinetic energy that the ejected electrons will have when the
metal is illuminated with this light.
(1)
Total marks: 10
25
Homework 23 – Interference
1. An experiment is set up to investigate interference effects and a pattern of dark
and bright fringes is produced.
Explain, in terms of waves, how the pattern of bright and dark fringes are
produced.
(2)
2. Microwaves are passed through two slits, A and B, in a metal plate as shown in
the diagram below.
A microwave detector is moved along a straight line from X to Y. The first
minimum of microwave intensity is detected at point P. The distance AP is 41 cm
and BP is 43 cm.
Find the wavelength of the microwaves.
(2)
3. A grating with 300 lines/mm is used with a spectrometer and a source of
monochromatic light to view an interference pattern as shown below.
The second maximum of interference is observed when the telescope is at an
angle of 24.5o. Calculate the wavelength of the light.
(3)
4. A grating or a prism can be used to produce spectra from a source of white light.
Give two differences between the spectra obtained using the grating and the
prism. Diagrams may be used to illustrate your answer.
(2)
Total marks: 9
26
Homework 24 – Refraction
1. A ray of red light has a wavelength of 700 nm in air. It is incident on a block of
plastic, and is refracted as shown below:
55°
35°
a) Calculate the refractive index of the block of plastic.
b) What is the wavelength of the red light in the block of plastic?
c) A blue light now replaces the red light. What happens to the angle of
refraction?
(2)
(2)
(1)
2. A physics student decides to propose to his girlfriend. Just as he is presenting the
diamond engagement ring to her, he notices the sparkling is caused by total
internal reflection. He is so taken by this observation, he rushes off to find out the
refractive index of diamond so that he can calculate the critical angle for the
diamond.
His girlfriend immediately dumped him.
a) If the refractive index of diamond is 2.42, calculate the critical angle.
b) What is meant by ‘critical angle’?
(2)
(1)
3. White light is shone onto a triangular glass prism. A spectrum is viewed on the
other side of the prism.
a) Why is a spectrum produced?
b) List the colours in order from most deflected to least deflected.
(1)
(1)
Total marks: 10
27
Homework 25 – Spectra
1. A light meter is used to measure the irradiance of light from a small lamp
At a distance of 1.5 m from the lamp, the irradiance of the light is 0.60 Wm -2.
What is the irradiance at a distance of 4.5 m from the lamp?
(2)
At a distance of 1.5 m from a laser, the irradiance of the laser light is 400 Wm-2.
What is the irradiance at a distance of 4.5 m from the laser?
(2)
2. The following diagram represents the energy levels of a particular metal’s atoms.
-5 x 10-19 J
-9 x 10-19 J
-16 x 10-19 J
-25 x 10-19 J
a) How many possible transitions are there for this atom?
b) Calculate the maximum frequency of light absorbed by this atom.
c) Which part of the spectrum would this absorption line be found in?
Explain your answer.
(1)
(2)
(2)
3. Explain why the absorption spectrum of an atom has dark lines corresponding to
frequencies present in the emission spectrum of the atom.
(2)
4. A laser used in a CD player emits monochromatic light of wavelength 840 nm.
a) When the light passes through a grating only one bright line is seen in the
spectrum. Explain why only one line appears in the emission spectrum of
the laser.
(1)
b) Calculate the difference in energy between the two energy levels that
produce photons with this wavelength.
(2)
Total marks: 14
28
Ink Exercises
Each of these exercises consist of both multiple choice and long answer questions.
All of these questions are of the same standard as those in the final exam.
29
Ink Exercise 1
1. A student sets up the apparatus in the diagram to measure the average
acceleration of a model car as it travels from P to Q.
For one run, the following measurements were recorded along with their
estimated errors:
clock 1 reading
clock 2 reading
stopwatch reading
length of car
distance PQ
= (0.23 ± 0.01) s
= (0.12 ± 0.01) s
= (0.95 ± 0.20) s
= (0.050 ± 0.0002) m
= (0.30 ± 0.01) m
The measurement which gives the largest percentage error is the
A
B
C
D
E
reading on clock 1
reading on clock 2
reading on the stopwatch
length of car
distance PQ
1
2. A car accelerates uniformly from rest and travels a distance of 60 m in 6 s. The
acceleration of the car, in ms-2, is
A
B
C
D
E
0.83
3.3
5.0
10
20
1
30
3. Consider the following three statements made by pupils about scalars and
vectors.
I
II
III
Scalars have direction only.
Vectors have both size and direction.
Speed is a scalar and velocity is a vector.
Which statement(s) is/are true?
A
B
C
D
E
I only
I and II only
I and III only
II and III only
I, II and III only
1
4. A stunt motorcyclist attempts to jump a river which is 5 m wide. The bank from
which he will take off is 2 m higher than the bank on which he will land as
shown below.
What is the minimum horizontal speed he must achieve just before take-off to
avoid landing in the river?
A
B
C
D
E
2.0 ms-1
3.2 ms-1
7.9 ms-2
10.0 ms-1
12.5 ms-1
1
31
5. A ball is thrown vertically upwards from ground level. When it falls to the
ground, it bounces several times before coming to rest. Which one of the
following velocity-time graphs represents the motion of the ball from the
instant it leaves the thrower’s hand until it hits the ground for a second time.
A
B
C
D
E
1
32
6. The manufacturers of tennis balls require that the balls meet a given standard.
When dropped from a certain height onto a test surface, the balls must rebound
to within a limited range of heights.
The ideal ball is one which, when dropped from rest from a height of 3.15 m,
rebounds to a height of 1.75 m as shown below.
a)
b)
Assuming air resistance is negligible, calculate
(i) the speed of an ideal ball just before contact with the ground
(ii) the speed of this ball just after contact with the ground.
3
When a ball is tested six times, the rebound heights are measured to
be
1.71 m, 1.78 m, 1.72 m, 1.76 m, 1.73 m, 1.74 m
Calculate
(i) the mean value of the height of the bounce
(ii) the random error in this value.
3
(6)
33
7. In an orienteering event, competitors navigate from the start to control points
around a set course.
Two orienteers, Andy and Paul, take place in a race in a flat area. Andy can run
faster than Paul, but Paul is a better navigator.
From the start, Andy runs 700 m north (000) then 700 m south-east (135) to
arrive at the first control point. He has an average running speed of 3 ms -1.
a)
b)
By scale drawing or otherwise, find the displacement of Andy, from the
starting point, when he reaches the first control point.
2
Calculate the average velocity of Andy between the start and the first
control point.
2
c)
Paul runs directly from the start to the first control point with an average
running speed of 2.5 ms-1.
Determine the average velocity of Paul.
2
d)
Paul leaves the starting point 5 minutes after Andy.
Show by calculation who is first to arrive at this control point.
3
(9)
34
8. a)
A sports car is being tested along a straight track.
(i)
b)
In the first test, the car starts from rest and has a constant
acceleration of 4.0 ms-2 in a straight line for 7.0 s.
Calculate the distance the car travels in 7.0 s.
2
(ii)
In a second test, the car again starts from rest and accelerates at
4.0 ms-2 over twice the distance covered in the first test.
What is the increase in the final speed of the car at the end of the
second test compared with the speed at the end of the first test. 3
(iii)
In a third test, the car reaches a speed of 40 ms-1. It then
decelerates at 2.5 ms-2 until it comes to rest.
Calculate the distance travelled by the car while it decelerates to
rest.
2
A student measures the acceleration of a trolley as it moves freely down a
sloping track.
The trolley has a card mounted on it. As it moves down the track the card
cuts off the light at each of the light gates in turn. Both the light gates are
connected to the computer which is used for timing.
The student uses a stopclock to measure the time it takes the trolley to
move from the first light gate to the second light gate.
(i)
(ii)
List all of the measurements that have to be made by the student
and the computer to allow the acceleration of the trolley to be
calculated.
1
Explain fully how each of these measurements is used in
calculating the acceleration of the trolley as it moves down the
slope.
2
(9)
35
Ink Exercise 2
1. A force of 15 N acts on a box as shown below.
Which entry in the following table correctly shows the horizontal and vertical
components of the force?
Horizontal component
(N)
Vertical component
(N)
A
15 sin 60°
15 sin 30°
B
15 cos 60°
15 sin 30°
C
15 sin 60°
15 cos 60°
D
15 cos 30°
15 sin 30°
E
15 cos 60°
15 sin 60°
1
2. A block of weight 1500 N is dragged along a horizontal road at constant speed by
a force of 500 N.
What is the frictional force between the block and the road?
A
B
C
D
E
3N
500 N
1000 N
1500 N
2000 N
1
36
3. A block of wood, of mass 2.0 kg, slides with a constant velocity down a slope.
The slope makes an angle of 30° with the horizontal as shown in the diagram.
What is the value of the force of friction acting on the block.
A
B
C
D
E
1.0 N
1.7 N
9.8 N
17.0 N
19.6 N
1
4. A car of mass 900 kg pulls a caravan of mass 400 kg along a straight horizontal
road with an acceleration of 2 ms-2.
Assuming that the frictional forces are negligible, the tension in the coupling
between the car and caravan is
A
B
C
D
E
400 N
500 N
800 N
1800 N
2600 N
1
37
5. Two identical metal spheres X and Y are dropped onto a horizontal surface. The
distance Y falls is double the distance X falls.
Which of the following is/are true if the effects of air resistance are negligible?
I
II
III
Y takes twice as long to fall as X.
The maximum speed of Y is double the maximum speed of X.
The maximum kinetic energy of Y is double that of X.
A
B
C
D
E
I only
II only
III only
I and II only
I, II and III only
1
38
6. a)
A hot air balloon, of total mass 500 kg, is held stationary by a single vertical
rope.
(i) Draw a sketch of the balloon. On your sketch, mark and label all the
forces acting on the balloon.
1
(ii) When the rope is released, the balloon initially accelerates vertically
upwards at 1.5 ms-2. Find the magnitude of the buoyancy force.
2
(iii) Calculate the tension in the rope before it is released.
b)
2
An identical balloon is moored using two ropes, each of which makes an
angle of 25° to the vertical, as shown below.
By using a scale diagram, or otherwise, calculate the tension in each rope. 2
(7)
39
7. During a test on car safety, two cars are crashed together on a test track.
a)
Car A, which has a mass of 1200 kg and is moving at 18.0 ms-1, approaches
car B, which has a mass of 1000 kg and is moving at 10.8 ms-1, in the
opposite direction.
The cars collide head on, lock together and move off in the direction of
car A.
(i) Calculate the speed of the cars immediately after the collision.
2
(ii) Show by calculation that this collision is inelastic.
2
b)
During a second safety test, a dummy in a car is used to demonstrate the
effects of a collision.
During the collision, the head of the dummy strikes the dashboard at
20 ms-1 as shown below and comes to rest in 0.02 s.
The mass of the head is 5 kg.
(i) Calculate the average force exerted by the dashboard on the head of
the dummy during the collision.
2
(ii) The test on the dummy is repeated with an airbag which inflates during
the collision.
During the collision, the head of the dummy again travels forward at
20 ms-1 and is brought to rest by the airbag.
Explain why there is less risk of damage to the head of the dummy
when the airbag is used.
1
(7)
40
8. A child on a sledge slides down a slope which is at an angle of 20° to the
horizontal as shown below.
The combined weight of the child and the slope is 400 N. The frictional force
acting on the sledge and child at the start of the slide is 20.0 N.
a)
b)
(i) Calculate the component of the combined weight of the child and
sledge down the slope.
(ii) Calculate the initial acceleration of the sledge and child.
The child decides to start the slide from further up the slope. Explain
whether or not this has any effect on the initial acceleration.
2
2
1
(5)
41
9. A student performs an experiment to study the motion of the school lift as it
moves upwards.
The student stands on bathroom scales during the lift’s journey upwards.
The student records the reading on the scales at different parts of the lift’s
journey as follows.
Part of journey
Reading on scales
At the start (lift accelerating)
678 N
In the middle (steady speed)
588 N
At the end (lift decelerating)
498 N
a)
Show that the mass of the student is 60 kg.
1
b)
Calculate the initial acceleration of the lift.
2
c)
Calculate the deceleration of the lift.
1
d)
During the journey, the lift accelerates for 1.0 s, moves at a steady speed
for 3.0 s and decelerates for a further 1.0 s before coming to rest.
Sketch the acceleration-time graph for this journey.
2
(6)
42
Ink Exercise 3
1. An aeroplane is flying at 160 ms-1 in level flight 80 m above the ground. It
releases a package at a horizontal distance X from the target T.
The effect of air resistance can be neglected and the acceleration due to gravity
can be taken at 10 ms-2.
The package will score a direct hit on target t if X is
A
B
C
D
E
40 m
160 m
320 m
640 m
2560 m
1
2. The siren on a fire engine has a frequency of 260 Hz. The fire engine is moving
away from a stationary observer at 36 km h-1. The frequency heard by the
observer is
A
B
C
D
E
235 Hz
253 Hz
260 Hz
268 Hz
291 Hz
1
43
3. The distance between the Earth and the Moon is 3.84 x 10 8 m. The mass of the
Earth is 5.98 x 1024kg and the mass of the moon is 7.35 x 1022 kg. The
gravitational force between the Earth and the Moon is
A
B
C
D
E
2.74 x 10-3 N
1.99 x 1020 N
7.63 x 1028 N
2.98 x 1030 N
1.14 x 1039 N
1
4. A pupil makes the following statements about a star receding from Earth.
I
II
III
The light from a star will be red shifted.
The light from the star will be shifted to a higher wavelength.
The light from the star is shifted to a lower frequency.
Which statement(s) is/are correct?
A
B
C
D
E
I only
II only
III only
I and II only
I, II and III only
1
5. A starship at rest is 12 m long. The starship then travels past a stationary
observer at 0.8c. How long does the starship appear to be to the observer when
in motion.
A
B
C
D
E
7.2 m
12 m
13.5 m
16.4 m
15.2 m
1
6. The universe has constantly cooled down as it expands. The temperature of the
universe can be calculated by measuring the peak wavelength of background
A
B
C
D
E
Infra Red
Radio waves
Ultra Violet
Microwaves
X – rays
1
44
6. The fairway on a golf course is in two horizontal parts separated by a steep bank
as shown below.
A golf ball at point O is given an initial velocity of 41.7 ms-1 at 36° to the
horizontal.
The ball reaches a maximum vertical height at point P above the upper fairway.
Point P is 19.6 m above the upper fairway as shown. The ball hits the ground at
point Q.
The effect of air friction on the ball may be neglected.
a)
b)
c)
Calculate
(i) the horizontal component of the initial velocity of the ball;
(ii) the vertical component of the initial velocity of the ball.
1
1
Show that the time taken for the ball to travel from point O to point Q
is 4.5 s.
3
Calculate the horizontal distance travelled by the ball.
2
(7)
45
7. A Russian Soyuz rocket has launched from French Guiana to put six satellites in
orbit.
One satellite, Pleiades-1, is designed to produce pictures that resolve features
on the ground as small as 50 cm across.
Lift-off occurred on schedule at 23.03 local time, Friday 16 December 2011 with
Pleiades-1 being dropped off in its 700 km high polar orbit some 55 minutes
later. The 970 kg satellite is the result of a near-decade-long programme in the
French space agency (CNES) to develop one of the most powerful Earth
observation systems in the world.
(Mass of the Earth = 5.98 x 1024kg)
a)
State Newton’s Law of Gravitation.
1
b)
Calculate the size of the gravitational force on the satellite in its orbit.
2
c)
Calculate the size of the gravitational field strength in this orbit .
2
(5)
8. A starship 20 m long is travelling at a constant speed of 0·95 c. The spacecraft
travels at this speed for 2 days, as measured by a clock on the Earth.
a)
Calculate how many days have passed, as measured by a clock in the
starship.
2
b)
Calculate the distance travelled by the starship as measured by an observer
on the starship in metres.
1
c)
Calculate the length of the starship as observed by a person on earth, as it
travels at 0.95c.
2
(5)
46
9. In ‘Star Trek’ the spaceship U.S.S. Enterprise travels at 0.25c using impulse
power. The spaceship is 725 m long.
a)
b)
c)
Calculate what length a stationary observer on the planet Vulcan would
view the ship to be.
2
The ship emits a light flare of wavelength 500 nm. What wavelength
would the stationary observer view when the ship was moving away
from them at 2.0 x107 m s-1 ?
3
The crew of the U.S.S. Enterprise observe a galaxy receding from the ship
at 2.5 x106 ms-1. Calculate how far away from the ship the galaxy is.
2
(7)
47
Ink Exercise 4
1. The diagram below shows the screen and the settings of an oscilloscope, which
is being used to measure the output frequency of a signal generator.
What is the frequency of the signal applied to the input of the oscilloscope?
A
B
C
D
E
2.5 Hz
12.5 Hz
40 Hz
250 Hz
500 Hz
1
2. The farad is the unit of capacitance.
Which of the following units is equivalent to the farad?
A
B
C
D
E
CV-1
JC-1
AV-1
Js-2
Cs-1
1
48
3. A battery has an e.m.f. of 6.0 v and an internal resistance of 2.0 W. It is
connected to a 10.0 W resistor, as shown below.
The p.d. across the 10.0 W resistor is
A
B
C
D
E
1.0 V
1.2 V
4.8 V
5.0 V
6.0 V
1
4. The energy stored in a capacitor, of capacitance C, when holding a charge Q is
given by
A
B
C
D
E
½ QC
½ Q/C2
½ Q2/C
½ QC2
½ Q2C
1
49
5. In the following circuit, the p.d. across the 16 W resistor is 40 v when switch S is
open.
The p.d. across the 16.0 W resistor when switch S is closed is
A
B
C
D
E
12 V
15 V
30 V
45 V
48 V
1
50
6. The following circuit is set up to investigate the charging of a capacitor.
At the start of the experiment the capacitor is uncharged.
a)
The graph below shows how the p.d. VC across the capacitor varies with
time from the instant the switch S is closed.
Sketch a graph showing how the p.d. VR across the resistor varies with time
during the first 10 s of charging.
2
b)
c)
Calculate the current in the circuit at the instant the p.d. across the
capacitor is 6.0 V.
2
(i) When the capacitor is fully charged, it is removed from the circuit and
connected across a 10 W resistor.
What is the total energy dissipated in the resistor?
2
(ii) In another experiment, the fully charged capacitor is connected across
a 20 W resistor instead of the 10 W resistor.
How does the energy dissipated in this resistor compare with that
calculated in part (i)?
You must justify your answer.
1
(7)
51
7. The circuit below includes a cell with an e.m.f. of 1.60 V and internal resistance r.
The following readings are taken from the meters.
reading on the ammeter
= 0.04 A
reading on the voltmeter, V1 = 1.20 V
reading on the voltmeter, V2 = 0.30 V
a)
Calculate the value of the lost volts in the circuit.
1
b)
Calculate the internal resistance, r, of the cell.
2
c)
(i) The resistance of the variable resistor is altered so that the reading on
the ammeter is 0.02 A. What is the resistance of the variable resistor
now?
2
(ii) The resistance, R, of the variable resistor is now decreased. What effect
has this on the terminal potential difference, Vtpd, of the cell?
You must justify your answer.
3
(8)
52
8. A capacitor is connected across a variable frequency supply as shown in the
circuit below. The output of the supply has constant amplitude.
a)
(i) At a certain frequency, the current in the circuit is 200 mA r.m.s.
Calculate the value of the peak current in the circuit.
2
(ii) The frequency of the output from the supply is now slowly increased.
Sketch the graph of current against frequency for this circuit. Numerical
values are not supplied but the axes should be clearly labelled.
1
(3)
9. In an experiment to measure the capacitance of a capacitor, a student sets up
the following circuit.
When the switch is in position X, the capacitor charges up the supply voltage, VS.
When the switch is in position Y, the coulombmeter indicates the charge stored
by the capacitor.
The student records the following measurements and uncertainties.
Reading on voltmeter
Reading on coulombmeter
= (2.56 ± 0.01) V
= (3.2 ±n1) mC
calculate the value of the capacitance and the percentage uncertainty in this
value. You must give the answer in the form
value ± percentage uncertainty
(3)
53
10. The circuit below is used to determine the internal resistance r of a battery of
e.m.f. E.
The variable resistor provides known values of resistor R.
For each value of resistance R, the switch S is closed and the current I is noted.
For each current, the value of 1/I is calculated.
In one such experiment, the following graph of R against 1/I is obtained.
a)
Conservation of energy applied to the complete circuit gives the following
relationship.
E = I(R + r)
Show that this relationship can be written in the form
R = (E/I) – r
1
b)
Use information from the graph to find:
(i) the internal resistance of the battery;
(ii) the e.m.f. of the battery.
1
2
(4)
54
Ink Exercise 5
1. Certain materials can be “doped” to make a semiconductor called an n-type
material.
In an n-type material,
A
B
C
D
E
the majority charge carriers are electrons
the majority charge carriers are neutrons
the majority charge carriers are protons
there are more electrons than protons
there are more electrons than neutrons
1
2. A student reads the following passage in a physics dictionary.
“….a solid state device in which positive and negative charge carriers are
produced by the action of light on a p-n junction.”
The passage describes a
A
B
C
D
E
light emitting diode
laser
capacitor
photodiode
thermistor
1
3. A crystal of silicon is “doped” with arsenic, that is, a small number of the silicon
atoms are replaced with arsenic atoms.
The effect of the doping on the crystal is to
A
B
C
D
E
make it into a photodiode
make it into an insulator
increase its resistance
decrease its resistance
allow it to conduct in only one direction
1
55
4. Which of the following statements is/are true?
I
III
In a light emitting diode, positive and negative charge carriers recombine to
emit light.
In a p-n junction diode, the majority carriers in the p-type material are
electrons.
In a photodiode, electron-hole pairs are produced by the action of light.
A
B
C
D
E
I only
I and II only
I and III only
II and III only
I, II and III
II
1
5. Which one of the following graphs shows the relationship between the current I
in a p-n Junction diode and the voltage across the diode.
A
B
C
D
E
56
6. The circuit below shows a photodiode connected in series with a resistor and an
ammeter. The power supply has an output voltage of 5V and negligible internal
resistance.
In a darkened room, there is no current in the circuit.
When light strikes the photodiode, there is a current in the circuit.
a)
(i) Describe the effect of light on the material of which the photodiode is
made.
1
(ii) In which mode is the photodiode operating.
1
(iii) The intensity of the light at the junction of the photodiode increases.
Describe and explain what happens to the current in the circuit.
1
b)
Light of a constant intensity is shone on the photodiode in the circuit
shown above.
The following measurements are obtained with S open and then with S
closed.
(i) What is the value of the e.m.f. produced by the photodiode for this
light intensity?
(ii) Calculate the internal resistance of the photodiode for this light
intensity.
c)
1
2
In the circuit above, the 20 W resistor is now replaced with a 20 W resistor.
The intensity of the light is unchanged. The following measurements are
obtained.
Explain why the reading on the voltmeter, when S is closed, is smaller than
the corresponding reading in part (b).
2
(8)
57
7. The diagram below represents the p-n junction of a light emitting diode (LED).
a)
Draw a diagram showing the above p-n junction connected to a battery so
that the junction is forward biased.
1
b)
When the junction is forward biased, there is a current in the diode.
Describe the movement of the charge carriers which produces this
current.
2
c)
Describe how the charge carriers in the light emitting diode enable light
to be produced.
2
d)
The following graph shows the variation of current with voltage for a diode
when it is forward biased.
(i) What is the minimum voltage required for the diode to conduct?
1
(ii) What happens to the resistance of the diode as the voltage is increased
above this minimum value?
Use information from the graph to justify your answer.
2
(8)
58
8. a)
b)
Materials may be classified as “conductors”, “semiconductors” and
“insulators”.
Give an example of a material from each of these groups.
1
An electronics textbook states that
“….p-type semiconductor material is formed by doping a pure
semiconductor material with impurity atoms.”
What is meant by the term “n-type” semiconductor material?
2
(3)
59
Ink Exercise 6
1. Hadrons are composite particles made of quarks. Up (u) quarks have a charge of
+ ⅔ e whilst down (d) quarks have a charge of - ⅓ e, where e is equal to the
magnitude of an electron’s charge. Antiquarks have the opposite charge to these
values.
Which line in the following table of data on hadrons is correct?
Hadron
A
B
C
D
E
Proton
Proton
Neutron
Neutron
Neutron
Quark
structure
udd
ddd
uū
uud
udd
Charge (e)
+1
+1
0
+1
0
1
2. Two parallel metal plates X and Y in a vacuum have a potential difference V
across them.
An electron of charge e and mass m, initially at rest, is released from plate X.
The speed of the electron when it reaches plate Y is given by
A
B
C
D
E
2eV/m
√(2eV/m)
√(2V/em)
2V/em
2mV/e
1
60
3. The diagram below shows a circuit with a 6.0 V battery connected to two
parallel metal plates A and B which are 0.30 m apart.
The amount of work needed to move 2 C of charge from plate A to B is
A
B
C
D
E
1.8 J
3.0 J
6.0 J
12.0 J
20.0 J
1
4. Which row in the table shows an example of a hadron, lepton and boson?
1
61
5. A particle accelerator increases the speed of protons by accelerating them
between a pair of parallel metal plates, A and B, connected to a power supply as
shown below.
The potential difference between A and B is 25 kV.
a)
Show that the kinetic energy gained by a proton between plates A and B
is 4.0 x 10-15 J
2
b)
The kinetic energy of a proton at plate A is 1.3 x 10 -16 J.
Calculate the velocity of the proton on reaching plate B.
3
The plates are separated by a distance of 1.2 m.
Calculate the force produced by the particle accelerator on a proton as
it travels between plates A and B.
2
Protons can be detected by their deflection in a magnetic field.
Copy and complete the diagram below, showing clearly the path of a
proton as it passes into the magnetic field.
1
c)
d)
Direction of
proton
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
(8)
62
6. Sub-atomic particles can be either hadrons or leptons.
a)
State one difference between these two groups of particles.
1
b)
Give an example of a hadron and an example of a lepton.
2
c)
Hadrons can be further divided into two groups. Name these two groups
and state a difference between them.
3
d)
A conversation is overheard between two young pupils who are discussing
their science lessons.
Pupil A “We learned in science today that the nucleus of an atom is made of
protons which are positively charged and neutrons which have no charge.”
Pupil B “That’s interesting because we learned in science that like charges
repel. How come the protons in the nucleus don’t fly apart?”
Pupil A “I don’t know.”
Write a paragraph that would explain to the pupils why the protons in a
nucleus do not fly apart.
3
(9)
7. In a famous experiment to investigate the structure of the atom, a beam of
radiation is directed at a thin, gold foil target as shown in the diagram below.
The experiment shows that most of the radiation passes through the gold foil
but some “bounces back” without passing through the foil.
a)
State the type of radiation used.
b)
Explain how the results of the experiment suggest that the mass of the
atom is concentrated at its centre.
1
2
(3)
63
Ink Exercise 7
1. To demonstrate the photoelectric effect, radiation is directed onto the surface of
a clean charged zinc plate.
Which of the following sets of conditions is required to produce the emission of
photoelectrons from the zinc plate?
1
2. An element X emits an alpha particle to form a new element.
Which of the following statements is/are correct about this new element?
I
II
III
The total number of protons and neutrons is 4 less than in element X.
The number of protons is the same as element X.
The new element is an isotope of element X.
A
B
C
D
E
I only
II only I only
III only
I and III only
II and III only
1
3. The minimum energy required to eject an electron from a certain metal is 3.0 x
10-19 J. Light of frequency 4.8 X 1014 Hz is incident on this metal.
Which of the following statements is correct?
A
B
C
D
E
Electrons will not be ejected from the metal.
Electrons will be ejected with 0 J of kinetic energy.
Electrons will be ejected with 1.8 x 10-20 J of kinetic energy.
Electrons will be ejected with 3.2 x 10-19 J of kinetic energy.
Electrons will be ejected with 6.2 x 10-19 J of kinetic energy.
1
64
4. Ultraviolet radiation is incident on a zinc plate. Photoelectrons with a certain
maximum kinetic energy are released from the zinc. The irradiance of the
ultraviolet radiation is now increased.
What happens to the maximum kinetic energy of the photoelectrons and the
rate at which they are released?
1
5. The three statements below refer to the fission process.
I
II
III
Fission may be spontaneous.
Fission can be produced when neutrons bombard a nucleus, which has a
large mass number.
When fission occurs, a nucleus with a large mass number may split into
nuclei with smaller mass numbers, along with several neutrons.
Which statements is/are true?
A
B
C
D
E
III only
I only II only
I and III only
II and III only
I, II and III
1
65
6. It is quoted in a text book that
“the work function of caesium is 3.04 x 10-19J”
a)
Explain what is meant by the above statement.
b)
In an experiment to investigate the photoelectric effect, a glass vacuum
tube is arranged as shown below.
1
The tube has two electrodes, one of which is coated with caesium.
Light of frequency 6.1 x 1014 Hz is shone on to the caesium coated
electrode.
(i) Calculate the maximum kinetic energy of a photoelectron leaving the
caesium coated electrode.
3
(ii) An electron leaves the caesium coated electrode with this maximum
kinetic energy.
Calculate its kinetic energy as it reaches the upper electrode when the
p.d. across the electrodes is 0.8 V.
3
c)
The polarity of the supply voltage is now reversed.
Calculate the minimum voltage which should be supplied across the
electrodes to stop photoelectrons from reaching the upper electrode.
2
(9)
66
7. The following statement represents a nuclear reaction which may form the basis
of a nuclear power station of the future.
a)
State the name given to the above type of nuclear reaction.
1
b)
Explain, using E = mc2, how this nuclear reaction results in the production
of energy.
2
c)
Using the information given below, and any other data required from the
Data Sheet, calculate the energy released in the above nuclear reaction.
3
d)
Calculate how many reactions of the type represented above would occur
each second to produce a power of 25 MW.
2
(8)
8. The first three stages in a radioactive decay series are shown below.
a)
What particle is emitted when Thorium (Th) decays to Palladium (Pa)?
1
b)
How many neutrons are in the nuclide represented by
1
c)
In the next stage of the above decay series, an alpha particle is emitted.
Copy and complete this stage of the radioactivity decay series shown
below, giving values for a, b, c and d, and renaming the element X.
?
3
(5)
67
9. The apparatus shown below is used to investigate photoelectric emission from
the metal surface, X, when electromagnetic radiation is shone on the surface.
The frequency of the electromagnetic radiation can be varied.
a)
When radiation of a certain frequency is shone on the metal surface X, a
reading is obtained on the ammeter.
Sketch a graph to show how the current in the circuit varies with the
irradiance of the radiation.
1
b)
Explain why there is no reading on the ammeter when the frequency of the
radiation is decreased below a particular value.
2
(3)
68
Ink Exercise 8
1. Light of frequency 6 x 1014 Hz passes from air to glass. The refractive index of the
glass is 1.5 and the speed of light is 3 x 10 8 ms-1.
The wavelength of this light in the glass is
A
B
C
D
E
5.0 x 10-9 m
3.3 x 10-7 m
5.0 x 10-7 m
7.5 x 10-7 m
1.8 x 1023 m
1
2. A space probe is positioned 3 x 1011 m from the Sun. It needs solar panels with
an area of 4 m2 to absorb sufficient energy from the Sun to keep it functioning
correctly.
What area of solar panels would be needed to keep the probe functioning
correctly if it is to be repositioned at a distance of 6 x 1011 m from the Sun?
A
B
C
D
E
1 m2
2 m2
4 m2
8 m2
16 m2
1
3. Which row in the following table gives the approximate wavelengths of red,
green and blue light in nanometres?
1
69
4. The diagram below shows some of the energy levels for the hydrogen atom.
The highest frequency of radiation emitted due to a transition between two of
these energy levels is
A
B
C
D
E
2.04 x 1020 Hz
1.63 x 1020 Hz
3.08 x 1015 Hz
2.46 x 1015 Hz
1.59 x 1014 Hz
1
5. A microwave transmitter is directed at a metal plate which has two slits P and Q
in it as shown. The microwave radiation emitted has a wavelength of 3 cm.
A microwave receiver is moved from R to S and, in doing so, detects maxima
and minima of intensity at the positions shown.
What is the path difference between PR and QR?
A
B
C
D
E
1.5 cm
3.0 cm
4.5 cm
6.0 cm
9.0 cm
1
70
6. A pupil finds a glass prism of the shape shown below when she dismantles an
old optical instrument.
To investigate the optical properties of the prism, she directs a narrow beam of
red light towards the prism as shown.
The glass has a refractive index of 1.52 for this red light.
a)
Calculate the value of the critical angle for this light in the glass prism.
2
b)
On graph paper, draw the prism with the dimensions stated in the diagram.
On your diagram, show the passage of the light beam until after it emerges
from the prism. Mark all relevant angles.
3
c)
A second beam of light, parallel to the first and of the same wavelength, is
now directed onto the prism at A.
Add to your diagram the complete path of this beam through the prism. 2
(7)
71
7. A biologist is studying the effect of different colours of light on a sample of
chlorophyll.
The biologist sets up the apparatus shown below, using a diffraction grating with
6.0 x 105 lines per metre to produce a first order spectrum of sunlight.
a)
Explain briefly how a diffraction grating produces a continuous spectrum
from the ray of sunlight.
2
b)
(i) The wavelength of the light at the end X of the spectrum is 410 nm.
Calculate the value of the angle q.
2
(ii) The angle A, in the diagram above, is 9°. Calculate the wavelength at
end Y of the spectrum.
3
c)
The biologist now uses a triangular glass prism to produce a continuous
spectrum from a ray of sunlight.
State two differences between this spectrum and the spectrum produced
by the grating.
2
(9)
72
8. The line emission spectrum of hydrogen has four lines in the visible spectrum as
shown in the following diagram.
These four lines are caused by the electron transitions in a hydrogen atom from
high energy levels to a low energy level E2 as shown below.
a)
From the information above, state which spectral line W, X, Y or Z is
produced by an electron transition from E3 to E2.
1
b)
Explain why lines Y and Z in the line emission spectrum are brighter than
the other two lines.
1
c)
Infrared radiation of frequency 7.48 x 1013 Hz is emitted from a hydrogen
atom.
(i) Calculate the energy of one photon of this radiation.
2
(ii) Show by calculation which electron transition produces this
radiation.
2
(6)
73
9. Two identical loudspeakers X and Y are set up in a room which has been
designed to eliminate the reflection of sound. The loudspeakers are connected
to the same signal generator as shown.
a)
When a sound level meter is moved from P to T, maxima and minima of
sound intensity are detected.
Explain, in terms of waves, why the maxima and minima are produced. 1
b)
The sound level meter detects a maximum at P.
As the sound level meter is moved from P, it detects a minimum then a
maximum then another minimum when it reaches Q.
Calculate the wavelength of the sound used.
2
(3)
74