32. (a) figure 1 shows a pair of parallel metal plates, a

Microsoft Word - PHY4 past paper questions completePolesworth High School 41
32. (a) Figure 1 shows a pair of parallel metal plates, A and B, fixed vertically 20 mm apart with
a potential difference of 1500 V between them.
0 V +1500 V
figure 1
20 mm
(i) Draw the electric field lines in the space between the plates and calculate the
electric field strength at P.
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(ii) Sketch a graph showing the potential at different points in the space between the
plates.
potential
Polesworth High School 42
(b) Figure 2 shows a polystyrene ball of mass 5.0 × 10–4 kg suspended midway between the
plates by a long insulating thread. The ball has a conducting surface and carries an
initial charge of –3.0 nC.
0 V +1500 V
figure 2
20 mm
(i) Calculate the force on the ball due to the electric field and hence show that the ball,
when released from rest, will take a time of approximately 0.2 s to reach one
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(ii) Explain why the ball will subsequently shuttle backwards and forwards between
the plates and discuss whether or not you consider this motion to be simple
harmonic.
(c) The same charged ball described in part (b) is suspended at rest between the poles of a
magnet. State the magnitude and direction of the force (if any) on the ball and explain
your answer.
(Total 15 marks)
33. The diagram shows a magnet placed on a top-pan balance. A fixed horizontal wire, through
which a current can flow, passes centrally through the magnetic field parallel to the pole-pieces.
With no current flowing, the balance records a mass of 201.32g. When a current of 5.0A
flows, the reading on the balance is 202.86 g.
south pole
north pole
201.32 g top-pan balance
(a) (i) Explain why the reading on the balance increased when the current was switched
on.
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(iii) If the length of the wire in the magnetic field is 60 mm, estimate the flux density of
the magnetic field.
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(b) Sketch a graph to show how you would expect the balance reading to change if the
current through the wire was changed.
balance reading
current (2)
(Total 8 marks)
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G
G
h
A bullet of mass 0.010 kg travelling at a speed of 200 m s–1 strikes a block of wood of
mass 0.390 kg hanging at rest from a long string. The bullet enters the block and lodges in
the block. Calculate
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(c) During the collision of the bullet and block, kinetic energy is converted into internal
energy which results in a temperature rise.
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(ii) Show that the kinetic energy of the combined block and bullet immediately after
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(iii) The material from which the bullet is made has a specific heat capacity of
250 J kg–1 K–1. Assuming that all the lost kinetic energy becomes internal energy
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(d) The bullet lodges at the centre of mass G of the block. Calculate the vertical height h
through which the block rises after the collision.
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(Total 13 marks)
35. (a) Collisions can be described as elastic or inelastic. State what is meant by an inelastic
collision.
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(b) A ball of mass 0.12 kg strikes a stationary cricket bat with a speed of 18 m s–1. The ball is
in contact with the bat for 0.14 s and returns along its original path with a speed of
15 m s–1.
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36. The diagram shows a gymnast of weight 720N hanging centrally from two rings, each attached
to cables which hang vertically.
×
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(b) The diagram shows the gymnast after he has raised his body so that his centre of mass
moves through a vertical distance of 0.60 m.
×centre of mass
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(c) The gymnast now raises his legs so that they become horizontal, without raising the rest
of his body. State and explain whether his gravitational potential energy is changed by
this manoeuvre.
37. A simple pendulum and a mass-spring system are taken to the Moon, where the gravitational
field strength is less than on Earth. Which line, A to D, correctly describes the change, if any, in
the period when compared with its value on Earth?
period of pendulum period of mass-spring system
A decrease decrease
B increase increase
(Total 2 marks)
38. A body moves with simple harmonic motion of amplitude A and frequency π
b
2 .
What is the magnitude of the acceleration when the body is at maximum displacement?
A zero
l
Y
A ball of mass m, which is fixed to the end of a light string of length l, is released from rest at
X. It swings in a circular path, passing through the lowest point Y at speed υ. If the tension in
the string at Y is T, which one of the following equations represents a correct application of
Newton’s laws of motion to the ball at Y?
A T = mg l
(Total 2 marks)
40. The gravitational potential difference between the surface of a planet and a point P, 10 m above
the surface, is 8.0 J kg –1
. Assuming a uniform field, what is the value of the gravitational field
strength in the region between the planet’s surface and P?
A 0.80 N kg–1
B 1.25 N kg –1
C 8.0 N kg–1
D 80 N kg –1
(Total 2 marks)
41. If the potential difference between a pair of identical, parallel, conducting plates is known, what
is the only additional knowledge required to determine the electric field strength between the
plates?
B the separation and area of the plates
C the separation and area of the plates and the permittivity of the medium between the
plates
D the separation of the plates (Total 2 marks)
42. Which one of the following statements about electric field strength and electric potential is
incorrect?
B Electric field strength is a vector quantity.
C Electric potential is zero whenever the electric field strength is zero.
D The potential gradient is proportional to the electric field strength. (Total 2 marks)
43. Which line, A to D, gives correct units for both magnetic flux and magnetic flux density?
magnetic flux magnetic flux destiny
A Wb m–2 Wb
B Wb T
axle
I
I
A coil, mounted on an axle, has its plane parallel to the flux lines of a uniform magnetic field B,
as shown. When a current I is switched on, and before the coil is allowed to move,
A there are no forces due to B on the sides SP and QR.
B there are no forces due to B on the sides PQ and RS.
C sides SP and QR tend to attract each other.
D sides PQ and RS tend to attract each other. (Total 2 marks)
P Q R
Three identical magnets P, Q and R are released simultaneously from rest and fall to the ground
from the same height. P falls directly to the ground, Q falls through the centre of a thick
conducting ring and R falls through a ring which is identical except for a gap cut into it. Which
one of the statements below correctly describes the sequence in which the magnets reach the
ground?
A P and R arrive together followed by Q.
B P and Q arrive together followed by R.
C P arrives first, followed by Q which is followed by R.
D All three magnets arrive simultaneously. (Total 2 marks)
200 g
500 g
(a) When a 200 g mass is suspended from a spring, as in Figure 1, it produces an extension
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(b) A spring identical to that in part (a) is joined to the lower end of the original one and a
500 g mass is suspended from the combination, as shown in Figure 2.
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(ii) When the 500 g mass is displaced it performs small vertical oscillations. Calculate
the number of oscillations made in one minute.
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(Total 5 marks)
47. (a) A 2.0 µF capacitor is charged through a resistor from a battery of emf 4.5 V. Sketch a
graph on the axes below to show how the charge stored, Q, varies with the potential
difference, V, across the capacitor during the charging process. Mark appropriate values
on the axes of the graph.
V
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(ii) Calculate the energy stored by the capacitor in part (a) when the potential
difference across it is 1.5 V.
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(Total 7 marks)
48. (a) An electron moves parallel to, but in the opposite direction to, a uniform electric field, as
shown in Figure 1.
Figure 1
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(b) An electron, which is travelling in a horizontal path at constant speed, enters a uniform
vertical electric field as shown in Figure 2.
electric field
Figure 2
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49. The simplified diagram shows an experimental arrangement to investigate the collision of two
trolleys.
card Light gate G Light gate G1 2
In the experiment, trolley A is travelling at speed ν. It collides with and sticks to, the initially
stationary trolley B.
(a) State the measurements you would need to take so that you could determine the speed of
(i) trolley A before the collision,
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(b) Explain how you would verify that momentum was conserved in this collision, indicating
what other measurements would be required.
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(c) State and explain what you would do to minimise the effects of friction on the motion of
the trolleys.
(Total 7 marks)
50. A mass M hangs in equilibrium on a spring. M is made to oscillate about the equilibrium
position by pulling it down 10 cm and releasing it. The time for M to travel back to the
equilibrium position for the first time is 0.50 s. Which line, A to D, is correct for these
oscillations?
A 10 1.0
B 10 2.0
C 20 2.0
D 20 1.0
(Total 2 marks)
51. A wave motion has period T, frequency f, wavelength λ and speed υ. Which one of the
following equations is incorrect?
52. Which one of the following statements is true when an object performs simple harmonic motion
about a central point O?
A The acceleration is always away from O.
B The acceleration and velocity are always in opposite directions.
C The acceleration and the displacement from O are always in the same direction.
D The graph of acceleration against displacement is a straight line. (Total 2 marks)
53. A girl of mass 40 kg stands on a roundabout 2.0 m from the vertical axis as the roundabout
rotates uniformly with a period of 3.0 s. The horizontal force acting on the girl is approximately
A zero.
D 2.8 × 104 N. (Total 2 marks)
54. Which one of the following graphs correctly shows the relationship between the gravitational
force, F, between two masses and the distance, r, between them?
F
A
r
F
B
(Total 2 marks)
55. For a particle moving in a circle with uniform speed, which one of the following statements is
incorrect?
A The velocity of the particle is constant.
B The force on the particle is always perpendicular to the velocity of the particle.
C There is no displacement of the particle in the direction of the force.
D The kinetic energy of the particle is constant. (Total 2 marks)
56. A satellite is in orbit at a height h above the surface of a planet of mass M and radius R. What is
the velocity of the satellite?
A R
0.5 m 0.5 m 0.5 m 0.5 m
50 V 40 V 30 V 20 V 10 V (potential)
R P S
The diagram shows how the electric potential varies along a line XX’ in an electric field. What will be the electric field strength at a point P on XX’ which is mid-way between R and S?
A 5.0 V m –1
B 10 V m–1
C 20 V m–1
D 30 V m –1
(Total 2 marks)
Q
P
A wire lies perpendicularly across a horizontal uniform magnetic field of flux density
20 × 10–3 T so that 0.30 m of the wire is effectively subjected to the field. If the force exerted on
this length of wire due to a current in it is 30 × 10 –3
N downward, what is the current in the
wire?
D 5.0 A from Q to P (Total 2 marks)
59. An electron moves due North in a horizontal plane with uniform speed. It enters a uniform
magnetic field directed due South in the same plane. Which one of the following statements
concerning the motion of the electron in the magnetic field is correct?
A It continues to move North with its original speed.
B It slows down to zero speed and then accelerates due South.
C It is accelerated due West.
D It is accelerated due North. (Total 2 marks)
60. To celebrate the Millennium in the year 2000, a footbridge was constructed across the River
Thames in London. After the bridge was opened to the public it was discovered that the
structure could easily be set into oscillation when large numbers of pedestrians were walking across it.
(a) What name is given to this kind of physical phenomenon, when caused by a periodic
driving force?
(b) Under what condition would this phenomenon become particularly hazardous? Explain
your answer.
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(c) Suggest two measures which engineers might adopt in order to reduce the size of the
oscillations of a bridge
61. A student used a voltage sensor connected to a datalogger to plot the discharge curve for a
4.7 µF capacitor. She obtained the following graph.
6
4
2
0
potential difference/V
(a) the initial charge stored,
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(Total 10 marks)
62. A rectangular coil measuring 20 mm by 35 mm and having 650 turns is rotating about a
horizontal axis which is at right angles to a uniform magnetic field of flux density 2.5 × 10 –3
T.
The plane of the coil makes an angle θ with the vertical, as shown in the diagrams.
N
axis
(a) State the value of θ when the magnetic flux through the coil is a minimum.
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(Total 5 marks)
63. (a) When an α particle is emitted from a nucleus of the isotope Bi212 83 , a nucleus of thallium,
Tl, is formed. Complete the equation below.
Bi212 83 → α + Tl
(2)
(b) The α particle in part (a) is emitted with 6.1 MeV of kinetic energy.
(i) The mass of the α particle is 4.0 u. Show that the speed of the α particle
immediately after it has been emitted is 1.7 × 10 –7
m s –1
. Ignore relativistic effects.
(ii) Calculate the speed of recoil of the daughter nucleus immediately after the α
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(Total 8 marks)
64. Protons and pions are produced in a beam from a target in an accelerator. The two types of
particles can be separated using a magnetic field.
(a) State the quark composition of
(i) a proton,
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(b) A narrow beam consisting of protons and positive pions, all travelling at a speed of
1.5 ↔ 10 7 m s
–1 , is directed into a uniform magnetic field of flux density 0.16 T, as
shown in the diagram.
proton path
uniform magnetic field perpendicular to the plane of the diagram
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(ii) Sketch, on the diagram above, the path of the pions from the point of entry into the
field to the point of exit from the field.
(iii) If the magnetic field were increased, how would this affect the paths of the
particles?
(Total 9 marks)
65. (a) A satellite moves in a circular orbit at constant speed. Explain why its speed does not
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(b) At a certain point along the orbit of a satellite in uniform circular motion, the Earth’s
magnetic flux density has a component of 56 µT towards the centre of the Earth and a
component of 17 µT in a direction perpendicular to the plane of the orbit.
satellite orbit
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(ii) The satellite has an external metal rod pointing towards the centre of the Earth.
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(Total 7 marks)
66. The diagram represents part of an experiment that is being used to estimate the speed of an air
gun pellet.
pellet θ
tr olley
The pellet which is moving parallel to the track, strikes the block, embedding itself. The trolley
and the block then move along the track, rising a vertical height, h.
(a) Using energy considerations explain how the speed of the trolley and block immediately
after it has been struck by the pellet, may be determined from measurements of h.
Assume frictional forces are negligible.
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mass of trolley and block 0.50 kg
mass of pellet 0.0020 kg
speed of trolley and block immediately after impact 0.40 m s–1
Calculate
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(Total 11 marks)
67. A girl kicks a ball along the ground at a wall 2.0 m away. The ball strikes the wall normally at a
velocity of 8.0 m s –1
and rebounds in the opposite direction with an initial velocity of
6.0 m s–1. The girl, who has not moved, stops the ball a short time later.
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(c) The ball has a mass of 0.45 kg and is in contact with the wall for 0.10 s. For the period of
time the ball is in contact with the wall,
(i) calculate the average acceleration of the ball.
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(iii) state the direction of the average force acting on the ball.
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(Total 8 marks)
68. Which one of the following gives the phase difference between the particle velocity and the particle displacement in simple harmonic motion?
A 4
π rad
B 2
π rad
C 4
3π rad
69. A particle oscillates with undamped simple harmonic motion. Which one of the following
statements about the acceleration of the oscillating particle is true?
A It is least when the speed is greatest.
B It is always in the opposite direction to its velocity.
C It is proportional to the frequency.
D It decreases as the potential energy increases. (Total 2 marks)
70.
0.8 m P
A model car moves in a circular path of radius 0.8 m at an angular speed of 2
π rad s
–1 .
What is its displacement from point P, 6 s after passing P?
A zero
71. A small mass is situated at a point on a line joining two large masses ml and m2 such that it
experiences no resultant gravitational force. If its distance from the mass m1 is r1 and its
distance from the mass m2 is r2, what is the value of the ratio 2
1
r
r ?
(Total 2 marks)
72. Which one of the following has different units to the other three?
A gravitational potential
D gravitational potential gradient (Total 2 marks)
73. Two horizontal parallel plate conductors are separated by a distance of 5.0 mm in air. The lower
plate is earthed and the potential of the upper plate is + 50 V.
Which line, A to D, gives correctly the electric field strength, E, and the potential, V, at a point midway between the plates?
electric field strength E/V m–1 potential V/V
A 1 × 104 upwards 25
B 1 × 10 4 downwards 25
C 1 × 10 4 upwards 50
D 1 × 10 4 downwards 50
(Total 2 marks)
74. The diagram shows a vertical square coil whose plane is at right angles to a horizontal uniform
magnetic field B. A current, I, flows in the coil, which can rotate about a vertical axis OO’.
O
O
I
I
B
Which one of the following statements is correct?
A The forces on the two vertical sides of the coil are equal and opposite.
B A couple acts on the coil.
C No forces act on the horizontal sides of the coil.
D If the coil is turned through a small angle about OO’, it will remain in position. (Total 2 marks)
75. An α particle and a β– particle both enter the same uniform magnetic field, which is
perpendicular to their direction of motion. If the β– particle has a speed 15 times that of the α
particle, what is the value of the ratio
particleαonforceofmagnitude
particleβonforceofmagnitude –
D 112.5 (Total 2 marks)
76. A simple pendulum consists of a 25 g mass tied to the end of a light string 800 mm long. The
mass is drawn to one side until it is 20 mm above its rest position, as shown in the diagram.
When released it swings with simple harmonic motion.
800 mm
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(b) Show that the initial amplitude of the oscillations is approximately 0.18 m, and that the
.
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(c) Calculate the magnitude of the tension in the string when the mass passes through the
lowest point of the first swing.
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(Total 8 marks)
77. The mass of the nucleus of an isolated copper atom is 63 u and it carries a charge of +29 e. The
diameter of the atom is 2.3 × 10 –10
m.
+

32. (a) figure 1 shows a pair of parallel metal plates, a

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