This is physics past paper of A levels under the Cambridge university. solve it and improve your learning skills.

1. *2358498204*
Cambridge International Examinations
Cambridge International Advanced Subsidiary and Advanced Level
PHYSICS 9702/42
Paper 4 A Level Structured Questions Mock 2019
2 hours
Candidates answer on the Question Paper.
No Additional Materials are required.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams or graphs.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
Electronic calculators may be used.
You may lose marks if you do not show your working or if you do not use appropriate units.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
This document consists of 26 printed pages and 2 blank pages.
DC (NH/CGW) 143388/6
© UCLES 2018 [Turn over

2. 2
Data
speed of light in free space c = 3.00 × 108 m s−1
permeability of free space μ0 = 4π × 10−7 Hm−1
permittivity of free space ε0 = 8.85 × 10−12 Fm−1
(
1
4πε0
= 8.99 × 109 m F−1)
elementary charge e = 1.60 × 10−19 C
the Planck constant h = 6.63 × 10−34 Js
unified atomic mass unit 1u = 1.66 × 10−27 kg
rest mass of electron me = 9.11 × 10−31 kg
rest mass of proton mp = 1.67 × 10−27 kg
molar gas constant R = 8.31JK−1 mol−1
the Avogadro constant NA = 6.02 × 1023 mol−1
the Boltzmann constant k = 1.38 × 10−23 JK−1
gravitational constant G = 6.67 × 10−11 N m2 kg−2
acceleration of free fall g = 9.81m s−2

3. 3
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2
2
t
Formulae
uniformly accelerated motion s = ut +
1
at 2
v2 = u2 +2as
work done on/by a gas W = pΔV
gravitational potential φ = −
Gm
r
hydrostatic pressure p = ρgh
pressure of an ideal gas p =
1 Nm
〈c2〉3 V
simple harmonic motion a = − ω 2x
velocity of particle in s.h.m. v = v0 cos ωt
2 2
v = ± ω (x0
fsv
Doppler effect fo =
v ± v
- x )
s
electric potential V =
Q
4πε0r
capacitors in series 1/C = 1/C1 + 1/C2 + . . .
capacitors in parallel C = C1 + C2 + . . .
energy of charged capacitor W = 1
QV
electric current I = Anvq
resistors in series R = R1 + R2 + . . .
resistors in parallel 1/R = 1/R1 + 1/R2 + . . .
Hall voltage V =
BI
H ntq
alternating current/voltage x = x0 sin ω t
radioactive decay x = x0 exp(−λt )
decay constant λ =
0.693
1
2

4. 4
Answer all the questions in the spaces provided.
1 (a) (i) State what is meant by a line of force in a gravitational field.
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[1]
(ii) By reference to the pattern of the lines of gravitational force near to the surface of the
Earth, explain why the acceleration of free fall near to the Earth’s surface is approximately
constant.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[3]
(b) The Moon may be considered to be a uniform sphere that is isolated in space. It has radius
1.74 × 103 km and mass 7.35 × 1022 kg.
(i) Calculate the gravitational field strength at the Moon’s surface.
gravitational field strength = ............................................... N kg–1 [2]
(ii) A satellite is in a circular orbit about the Moon at a height of 320 km above its surface.
Calculate the time for the satellite to complete one orbit of the Moon.
time = ........................................................ s [3]

5. 5
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[Total: 9]
2 (a) (i) A gravitational field may be represented by lines of gravitational force.
State what is meant by a line of gravitational force.
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[1]
(ii) By reference to lines of gravitational force near to the surface of the Earth, explain why
the gravitational field strength g close to the Earth’s surface is approximately constant.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[3]
(b) The Moon may be considered to be a uniform sphere of diameter 3.4 × 103 km and mass
7.4 × 1022 kg. The Moon has no atmosphere.
During a collision of the Moon with a meteorite, a rock is thrown vertically up from the surface
of the Moon with a speed of 2.8 km s–1.
Assuming that the Moon is isolated in space, determine whether the rock will travel out into
distant space or return to the Moon’s surface.
[4]
[Total: 8]

6. 10
0 t1
3 (a) State two conditions necessary for a mass to be undergoing simple harmonic motion.
1. ...............................................................................................................................................
...................................................................................................................................................
2. ...............................................................................................................................................
...................................................................................................................................................
[2]
(b) A trolley of mass 950g is held on a horizontal surface by means of two springs attached to
fixed points P and Q, as shown in Fig. 4.1.
trolley
mass 950g
spring
P Q
Fig. 4.1
The springs, each having a spring constant k of 230Nm–1, are always extended.
The trolley is displaced along the line of the springs and then released.
The variation with time t of the displacement x of the trolley is shown in Fig. 4.2.
x
0
t
Fig. 4.2

7. [Turn over© UCLES
11
(i) 1. State and explain whether the oscillations of the trolley are heavily damped, critically
damped or lightly damped.
....................................................................................................................................
....................................................................................................................................
2. Suggest the cause of the damping.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
[3]
(ii) The acceleration a of the trolley of mass m maybe assumedto be given by the expression
2k
a = – d
m
nx .
1. Calculate the angular frequency ω of the oscillations of the trolley.
ω = ............................................... rads–1 [3]
2. Determine the time t1 shown on Fig. 4.2.
t1 = ....................................................... s [2]
[Total: 10]

8. 4 (a) A mass is undergoing simple harmonic motion with amplitude x0. The maximum velocity of
the mass has magnitude v0.
On Fig. 3.1, show the variation with displacement x of the velocity v of the mass.
v
v0
0
−x0 x00 x
−v0
Fig. 3.1
[2]
(b) A straight stiff wire carries a constant current in a region of uniform magnetic flux density.
The angle θ between the direction of the current and the direction of the magnetic field is
varied. The maximum force on the wire is F0.
On Fig. 3.2, show the variation with angle θ of the force F on the wire for values of θ between
0° and 90°.
F0
F
0
0 90
θ /°
Fig. 3.2
[2]

9. [Turn over© UCLES
13
(c) A sinusoidal supply has frequency 250 Hz and r.m.s. potential difference 2.8V.
On the axes of Fig. 3.3, show quantitatively the variation with time t of the voltage V for one
cycle of the varying voltage.
8
V/V
6
4
2
0 1 2 3 4 5
t/ms
−4
−6
−8
Fig. 3.3
[2]

10. 5 (a) Explain what is meant by the natural frequency of vibration of a system.
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[1]
(b) A block of metal is fixed to one end of a vertical spring. The other end of the spring is attached
to an oscillator, as shown in Fig. 4.1.
oscillator
spring
metal
block
Fig. 4.1
The amplitude of oscillation of the oscillator is constant.
The variation of the amplitude x0 of the oscillations of the block with frequency f of the
oscillations is shown in Fig. 4.2.
x0
0
f
Fig. 4.2

11. [Turn over© UCLES
15
(i) Name the effect shown in Fig. 4.2.
.......................................................................................................................................[1]
(ii) State and explain whether the block is undergoing damped oscillations.
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(c) State one example in which the effect shown in Fig. 4.2 is useful.
...................................................................................................................................................
...............................................................................................................................................[1]
[Total: 5]

12. 6 (a) Explain what is meant by the capacitance of a parallel plate capacitor.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
(b) Three parallel plate capacitors each have a capacitance of 6.0 μF.
Draw circuit diagrams, one in each case, to show how the capacitors may be connected
together to give a combined capacitance of
(i) 9.0μF,
[1]
(ii) 4.0μF.
[1]
(c) Two capacitors of capacitances 3.0 μF and 2.0μF are connected in series with a battery of
electromotive force (e.m.f.) 8.0V, as shown in Fig. 6.1.
3.0μF 2.0μF
8.0V
Fig. 6.1

13. [Turn over© UCLES
17
(i) Calculate the combined capacitance of the capacitors.
capacitance = ..................................................... μF [1]
(ii) Use your answer in (i) to determine, for the capacitor of capacitance 3.0 μF,
1. the charge on one plate of the capacitor,
charge = .......................................................... μC
2. the energy stored in the capacitor.
energy = ......................................... J [4]
[Total: 10]

14. 7 (a) Explain how a uniform magnetic field and a uniform electric field may be used as a velocity
selector for charged particles.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]

15. [Turn over© UCLES
19
(b) Particles having mass m and charge +1.6 × 10–19 C pass through a velocity selector.
They then enter a region of uniform magnetic field of magnetic flux density 94mT with speed
3.4 × 104
m s–1
, as shown in Fig. 8.1.
path of charged particle
velocity
selector
15.0 cm
uniform
magnetic field
into page
Fig. 8.1
The direction of the uniform magnetic field is into the page and normal to the direction in
which the particles are moving.
The particles are moving in a vacuum in a circular arc of diameter 15.0 cm.
Show that the mass of one of the particles is 20u.
[4]
(c) On Fig. 8.1, sketch the path in the uniform magnetic field of a particle of mass 22u having the
same charge and speed as the particle in (b). [2]
[Total: 9]

16. 8 (a) State what is meant by the magnetic flux linkage of a coil.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
(b) A coil of wire has 160 turns and diameter 2.4cm. The coil is situated in a uniform magnetic
field of flux density 7.5 mT, as shown in Fig. 9.1.
magnetic field
flux density
7.5mT 2.4cm
coil
160 turns
Fig. 9.1
The direction of the magnetic field is along the axis of the coil.
The magnetic flux density is reduced to zero in a time of 0.15 s.
Show that the average e.m.f. induced in the coil is 3.6mV.
[2]

17. [Turn over© UCLES
21
(c) The magnetic flux density B in the coil in (b) is now varied with time t as shown in Fig. 9.2.
10
B/mT
5
0 0.1 0.2 0.3 0.4 0.5
t/s
0.6
–5
–10
Fig. 9.2
Use data in (b) to show, on Fig. 9.3, the variation with time t of the e.m.f. E induced in the coil.
8
E/mV 6
4
2
0 0.1
–2
0.2 0.3 0.4 0.5
t/s
0.6
–4
–6
–8
Fig. 9. [4] [Total: 9]

18. 9 (a) State what is meant by electric potential at a point.
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(b) The centres of two charged metal spheres Aand B are separated by a distance of 44.0cm, as
shown in Fig. 7.1.
44.0 cm
sphere A sphere B
P
x
Fig. 7.1 (not to scale)
A moveable point P lies on the line joining the centres of the two spheres. Point P is a distance
x from the centre of sphere A. The variation with distance x of the electric potential V at point
P is shown in Fig. 7.2.
2.2
V/104 V
2.0
1.8
1.6
1.4
1.2
0 10 20 30 40 50
x /cm
Fig. 7.2

19. [Turn over© UCLES
17
(i) Use Fig. 7.2 to state and explain whether the two spheres have charges of the same, or
opposite, sign.
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[1]
(ii) A positively-charged particle is at rest on the surface of sphere A.
The particle moves freely from the surface of sphere A to the surface of sphere B.
1. Describe qualitatively the variation, if any, with distance x of the speed of the particle
as it
moves from x = 12cm to x = 25cm ............................................................................
....................................................................................................................................
passes through x = 26 cm ..........................................................................................
....................................................................................................................................
moves from x = 27 cm to x = 31cm ............................................................................
....................................................................................................................................
reaches x = 32cm ......................................................................................................
................................................................................................................................ [4]
2. The particle has charge 3.2 × 10–19 C and mass 6.6 × 10–27 kg.
Calculate the maximum speed of the particle.
speed = ................................................. m s–1 [2]
[Total: 9]

20. 10 A thin slice of conducting material has its faces PQRS and VWXY normal to a uniform magnetic
field of flux density B, as shown in Fig. 9.1.
magnetic field
flux density B
Q R
W X
direction of
motion of electrons
P S
V Y
Fig. 9.1
Electrons enter the slice at right-angles to face SRXY.
A potential difference, the Hall voltage VH, is developed between two faces of the slice.
(a) (i) Use letters from Fig. 9.1 to name the two faces between which the Hall voltage is
developed.
............................................................... and ............................................................... [1]
(ii) State and explain which of the two faces named in (a)(i) is the more positive.
...........................................................................................................................................
.......................................................................................................................................[2]

21. [Turn over© UCLES
19
(b) The Hall voltage VH is given by the expression
V =
BI
.H ntq
(i) Use the letters in Fig. 9.1 to identify the distance t.
.......................................................................................................................................[1]
(ii) State the meaning of the symbol n.
...........................................................................................................................................
.......................................................................................................................................[1]
(iii) State and explain the effect, if any, on the polarity of the Hall voltage when negative
charge carriers (electrons) are replaced with positive charge carriers, moving in the
same direction towards the slice.
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
[Total: 7]

22. –
11 (a) (i) Define magnetic flux.
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(ii) State Faraday’s law of electromagnetic induction.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(b) A solenoid has a coil C of wire wound tightly about its centre, as shown in Fig. 10.1.
coil C
solenoid
+
d.c. supply
Fig. 10.1
The coil C has 96 turns.
The uniform magnetic flux Φ (in weber) in the solenoid is given by the expression
Φ = 6.8 × 10–6 × I
where I is the current (in amperes) in the solenoid.

24. Calculate the average electromotive force (e.m.f.) induced in coil C when a current of 3.5A is
reversed in the solenoid in a time of 2.4ms.
e.m.f. = ....................................................... V [2]
(c) The d.c. supply in Fig. 10.1 is now replaced with a sinusoidal alternating supply.
Describe qualitatively the e.m.f. that is now induced in coil C.
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
[Total: 8]