TRIAL SEM 2 SMJK Yu Hua, Kajang 2022

Form : 6AS1 SMJK Yu Hua, Kajang, Selangor
Date : 8th August 2021 (Monday) STPM Trial Examination
Time : (11:40 – 1:10) am, 1 ½ h August 2022
Physics Paper 2
Number of printed pages :
Prepared by : Pn. Rosmaya Mokhtar
Verified by : Pn. Fazida bt Saipan@Saipol

Name:……………………………………………….

SECTION A. (15 marks)

Answer all questions.
1. A spherical surface of radius R containing charges – 2Q , + 3Q and + 4Q is shown in the diagram below.

What is the total electric flux which passes through the spherical surface?

A. 5Q B. 5Q C. 5Q D. Q
4oR2 4oR o o

2. A proton enters a uniform electric field at M and moves in a parabolic path to N as shown in the diagram below.

If the electric field strength is 600 Vm-1, what is the change in kinetic energy of the proton?

A. 3.8x10-17 J B. 4.8x10-17 J C. 6.1x10-17 J D. 8.6x10-17 J

3. A certain capacitor consists of a pair of parallel metal plates separated by a distance d in air. The capacitor is
charged then disconnected from the charging source and immersed in a liquid with permittivity ε. Which of the
following statements regarding the capacitor is correct?
A. Both the charge stored in the capacitor and its capacitance decreased.
B. Both the charge stored in the capacitor and its capacitance increased.
C. The capacitance of the capacitor increased but the potential difference across it decreased.
D. The capacitance of the capacitor decreased but the potential difference across it increased.

4. Two identical capacitors, K and L, which are connected in parallel to a battery are shown in the diagram below.?

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When switch S is opened, the potential difference across K is V, the charge stored is Q and L is uncharged. When
switch S is closed, what is the potential difference across L and the charge stored in L?

Potential difference Charge stored

A. V Q

B. V 2Q

C. ½ V Q

D. ½ V 2Q

5. The resistance of the bulb filament is 100  at a temperature of 100C. Its temperature coefficient of resistance is

0.005 C-1. Find the temperature when the resistance become 200 .

A. 200C B. 300C C. 400C D. 500C

6. The magnitude of the drift velocity of the charge carriers in a semiconductor is dependent on the following except
A. the type of charge
B. the electric current
C. the cross-sectional area
D. the number of charge per unit volume

7. Three resistors of resistance 3.0 , 5.0  and 8.0 , and three batteries of e.m.f 1.5 V, 6.0 V and 12 V are
connected in series as shown in the circuit below.

The electric potential at point A with respect to point B is

A. − 15 V B. − 4.6 V C. 15 V D. 4.6 V

8. A cell of e.m.f 2.0 V and negligible internal resistance is connected to a network of resistors as shown.

What is the current I? B. 0.33 A C. 0.50 A D. 1.50 A
A. 0.25 A 2

9. Find the magnitude of resistance R in the circuit shown below when no current flows through 5  resistor.

A. 20  B. 15  C. 10  D. 5 

10. Which source cannot produce a magnetic field ?

A. A solenoid B. A permanent magnet C. The Earth D. A conductor which carries current

11. Four wires in a horizontal plane each carry a current I is shown in the diagram below. They cross each other
without touching to form a square. Point P is at the centre of the square. The magnetic flux density at P due to one
wire only is B.

What is the strength and direction of the magnetic field at P due to all four wires ?

A. 3B out of the page B. 2B out of the page C. 3B into the page D. 2B into the page

12. In an experiment designed to measure the Earth’s magnetic field using the Hall effect, a copper bar 0.50 cm thick

is positioned along an east-west direction. If a current of 8.0 A in the conductor results in a Hall voltage of
5.1x10-12 V, what is the magnitude of the Earth’s magnetic field ?

(Assume that n = 8.48x1028 electrons m3 and that the plane of the bar is rotated to be perpendicular to the

direction of B)

A. 4.32x10-5 T B. 5.00x10-5 T C. 4.32x105 T D. 5.00x105 T

13. A circular conducting loop is connected to a battery and a switch S as shown in the diagram below.

Immediately after S is closed, the current through the loop changes at a rate 15 As-1 and the e.m.f induced in the

loop has a magnitude of 5.0 V. What is the self-inductance of the loop?

A. 3.0 H B. 5.8x10-1 H C. 3.3x10-1 H D. 4.4x10-2 H

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14. The variation of current I and voltage V with time t for a component X in an a.c circuit is shown in the graphs
below.

What is the component X?

A. A diode B. A capacitor C. A resistor D. An inductor

15. A pure resistor is connected to an a.c source with its current supply I = 4.00 sin 628t flows in the circuit.
Which statement is not true about the circuit?
A. The r.m.s current flows through the resistor is 2.8 A.
B. The peak value of the current flows through the resistor is 4.0 A.
C. The frequency of the current flows through the resistor is 100 Hz.
D. The maximum power dissipated from the resistor is 628 W.

SECTION B. (15 marks)
Answer all questions.

16. a) A positively charged sphere C is near a long insulated conductor AB.

Draw sketches to show how the potential V all around C varies with the distance from C measured along AB and
beyond
i) before
ii) after
AB is placed in position. [3 marks]

b) An alpha-particle A of charge +3.2x10-19 C and mass 6.8x10-27 kg is travelling with a velocity of 1.0x107 ms-1
directly towards a nitrogen nucleus N which has a charge of +11.2x10-19 C.

Calculate the closest distance of approach of A to N, assuming that A is initially a very long way from N
compared with the closest distance of approach. [4 marks]

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17. In the circuit diagram shown, the length of the slide is 100 cm and its resistance is 8.0 . R1 and R2 are 5.0  and
15.0  respectively. E is an accumulator of e.m.f 2.0 V and negligible internal resistance. When both the switches
S1 and S2 are open, the galvanometer G is balanced when the length AJ is 72.0 cm. When both S1 and S2 are
closed, the balanced length AJ is 15.0 cm

Calculate
a) The e.m.f of the cell E1. [ 2 mark]
b) The internal resistance of the cell E1. [2 marks]
c) The balance length AJ when S1 is open and S2 is closed. [2 marks]
d) The balance length AJ when S1 is closed and S2 is open. [2 marks]

SECTION C. (30 marks)
Answer any two questions in this section.
18. a) What do you understand by

i) resistance
ii) resistivity and
iii) electrical conductivity [3 marks]
b) Sketch graphs to show variation of resistivity with temperature for
i) a metal and
ii) a semiconductor [2 marks]
Explain the shape of the graphs in terms of motion of the charge carriers. [4 marks]
c) Calculate the resistance per unit length of a 22-gauge Nichrome wire of radius 0.321 mm.

Resistivity of nichrome, ρ = 1.5 × 10 − 6 Ω m . [2 marks]
i) If a potential difference of 10.0 V is maintained across a 1.00 m length of the Nichrome wire, what is the

current in the wire? [3 marks]
ii) The wire is melted down and recast with twice its original length. Find the new resistance RN as a multiple

of the old resistance Ro. [2 marks]

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19. a) i) Define magnetic flux density, B of a magnetic field. [1 mark]
ii) A long straight wire X carrying a current of 2.0 A is placed parallel to a shorter wire Y of length 0.05 m
carrying a current of 3.0 A as shown below. The two wires are separated by a distance of 0.10 m.

Determine the magnetic flux density, B at Y due to X. [2 marks]

b) i) State Faraday’s law and Lenz’s law. [2 marks]
ii) Derive an equation for induced e.m.f in a linear conductor at right angle to a uniform magnetic field.
[4 marks]

c) Figure below shows a strip of metal of length 6.5 cm, width 0.85 cm and thickness 0.76 mm.

The strip moves with constant speed through a magnetic field B of 1.2 mT. The direction of B is
perpendicular to the plane of the strip. A potential difference of 3.9 V is produced from P to Q.
i) Determine the speed of the strip, v. [2 marks]
ii) If a current I = 2.0 A is allowed to flow in the strip in the same direction as the speed v of the strip, it is
found that the potential difference across PQ is eliminated. Explain why this happens and calculate the
number of free electron per unit volume, n in the metal strip. [4 marks]

20. a) Distinguish between resistance and impedance. [2 marks]
b) A filament lamp and an inductor are connected in series with an a.c generator. If the frequency of the a.c
generator is increased, does the brightness of the lamp increase, decrease or remain the same?
Explain your answer. [3 marks]

c) A 6.0 V, 50 Hz a.c supply is connected to a 2.8  resistor, a 0.82 mF capacitor and a 20.0 mH inductor as
shown in the circuit diagram.

i) Sketch a phasor diagram to show the phase difference between the potential differences across the
resistor, capacitor and inductor.

ii) Calculate the impedance in the circuit
iii) What is the r.m.s current in the circuit?
iv) Find the r.m.s potential difference across the resistor, capacitor and inductor. [10 marks]

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Answer :
1. C
2. B
3. C
4. A
5. B
6. A
7. B
8. A
9. D
10. A
11. D
12. A
13. C
14. B
15. D
16. a)

b)

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17. a) E1 = (72)( 8 )(2) = 0.501 V
b)
100 8+15
c)
d) ( 5 )(0.501) = ( 15 )(2)

5+r 100

r = 3.35 

0.501 = (AJ)(2)

100

AJ = 25.1 cm

( 5 )(0.501) = ( AJ)( 8 )(2)

5+3.35 100 8+15

AJ = 43.1 cm

18. a) - it acts as insulator, so that charge does not flow across the capacitor
- it increases the capacitance of the capacitor

c) .
2

i)
ii)

.
19. ..

3

20. a) .
b)

4

c) i)
ii)

=
= 3.7 Ohm
ii)

= = 1.622
iv)

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