S4 PHYSICS CHAPTER TEST 4
Name:
TERM 3
Part A:
Class:
Part B:
Part C:
Total:
AY 1920
PART A: Multiple Choice
[10 Marks]
1. A student investigates the force on a bar magnet placed near a current-carrying coil. She
carries out three different experiments.
In experiment 1, the magnet is attracted to the coil.
Which row shows what happens in the other two experiments?
A
B
C
D
Experiment 2
Magnet attracted
Magnet attracted
Magnet repelled
Magnet repelled
Experiment 3
Magnet attracted
Magnet repelled
Magnet attracted
Magnet repelled
2. Which diagram shows the pattern of the magnetic field produced by a current-carrying
solenoid?
3. The potential divider shown is connected across a constant 12 V
supply. When R has a value of 20 Ω, the voltmeter readings are
equal. How do these readings change when the value of R is
reduced to 10 Ω?
A
B
C
D
Reading on V1
decreases
decreases
increases
increases
Reading on V2
decreases
increases
decreases
increases
1
4. The diagram shows part of a circuit used to switch street lamps on and off automatically.
In the evening it gets dark. Which row shows the effect on the resistance of the lightdependent resistor (LDR) and on the potential difference (p.d.) across it?
A
B
C
D
Resistance of LDR
Decreases
Decreases
Increases
Increases
p.d. across LDR
Decreases
Increases
Decreases
Increases
5. The diagram shows a flat, rectangular coil placed between the poles of a magnet.
There is a current in the coil that makes it turn in the direction shown in the diagram
Which change would make the coil turn in the opposite direction?
A. decreasing the current in the coil
B. increasing the number of turns on the coil
C. reversing both the direction of the current in the coil and the poles of the magnet
D. reversing only the direction of the current in the coil
6. A metal wire is placed between the poles of a magnet. The wire can be moved in each
of three directions OP, QR and ST.
In which direction or directions must the wire be moved to induce an e.m.f. across the
ends of the wire?
A OP only
B OP or ST
C QR
D ST only
2
7. A magnet is suspended from a spring so that it can
move freely inside a stationary coil. The coil is
connected
to
a
sensitive
centre-zero
galvanometer. The magnet repeatedly moves
slowly up and down.
What does the galvanometer show?
A. a constantly changing reading
B. a steady reading to the left
C. a steady reading to the right
D. a steady reading of zero
8. A coil is rotated steadily between the poles of a magnet. The coil is connected to an
oscilloscope.
Which graph shows the output voltage V against time t ?
9. The diagram shows a combination of logic gates.
Input P is at a logic state 0 (low) and input Q is at a logic state 1 (high).
What are the logic states at output X and at output Y?
A
B
C
D
Output X
0
0
1
1
Output Y
0
1
0
1
3
10. A village has to be supplied with electricity from a power station that is a long way
from the village. Which type of current should be used, and at which voltage?
A
B
C
D
Type of current
Alternating Current
Alternating Current
Direct Current
Direct Current
Voltage
High voltage
Low voltage
High voltage
Low voltage
PART B: Structure Questions
[20 Marks]
1. In Fig. 1.1, a 12 V battery supplies a current I to a circuit. The circuit contains a thermistor
and a 1000 Ω resistor in parallel, with a 500 Ω resistor in series.
Figure 1.1.
(a) At a certain temperature, the thermistor has a resistance of 1000 Ω.
Calculate the total current that flows at the circuit,
current = ............................... [2]
(b) The temperature of the thermistor is increased. Explain the effect of this change to the
voltage across the 500 Ω resistor.
…………………………………………………………………………………………………
…………………………………………………………………………………………………
…………………………………………………………………………………………..….[2]
[Total: 4]
4
2. A 240 V AC mains supply is connected to the primary coil of the transformer shown
in Fig.2.1. A lamp that gives full brightness with a 6 V supply is connected to the
secondary coil.
Figure 2.1.
(a) Suggest why soft iron is used as the core of the transformer.
................................................................................................................................ [1]
(c) Explain why the current can flow at the secondary coil in order to turn on the
lamp.
…………………………………………………………………………………………………
…………………………………………………………………………………………………
…………………………………………………………………………………………………
………...………………………………………………………………………………………
…………………...………………………………………………………………………... [3]
(d) The input current that flows at primary coil is 5A.
The efficiency of the transformer is 72.5%.
Calculate the output current in order to turn on the 6V lamp.
Output current = .................... [2]
[Total: 6]
5
3. A very sensitive, centre-zero voltmeter is connected to the two terminals of a
solenoid (long coil). Fig.3.1 shows the S pole of a cylindrical magnet being inserted
into the solenoid.
Figure 3.1.
(a) Explain the deflection of needle as the magnet is moving inward the solenoid.
…………………………………………………………………………………………………
…………………………………………………………………………………………………
…………………………………………………………………………………………………
…………………………………………………………………………………………………
………...……………………………………………………………………………………….
…………………...…………………………………………………………………………….
..………………………………………………………………………………….…………[3]
[Total: 3]
4. (a) Fig. 4.1 is a schematic diagram of an electronic circuit controlling a lamp.
Figure 4.1.
The output of the temperature sensor is high (logic 1) when it detects raised
temperatures. The output of the light sensor is high (logic 1) when it detects
raised light levels.
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The lamp is lit when the input to the relay is high (logic 1).
(i) Complete the truth table by giving the outputs of A and B.
Output of
light sensor
0
0
1
1
Output of
temperature sensor
0
1
0
1
Output of A
Output of B
[2]
(ii) State in which condition the lamp is on.
................................................................................................................................. [1]
(b) Fig. 4.2 shows a circuit that switches on a warning lamp when the temperature in
an oven falls below a set value.
Figure 4.2.
Explain, with reference to the components in the circuit and point P, why the
warning lamp is on when the temperature in the oven is below the set value
………………………………………………………………………………………………………
…...……………………………………………………………………………………….………...
…………...…………………………………………………………………………….………...…
………………………………………………………………………………………………...……
…………………………………………………………………………………...…………………
……………………………………………………………….……………………………………..
………………………………………………………………………………………………………
…...………………………………………………………………………………………………[4]
[Total: 7
7
PART C: Alternative to Practical Skills
[10 Marks]
1. A student is determining the resistance of a piece of wire.
Fig. 2.1 shows the circuit she uses.
Figure 2.2.
(a) Record the current I in the circuit, as shown on the ammeter in Fig. 2.2.
I = .....................................[1]
(b) The student places the sliding contact C at a distance l = 20.0 cm from P. The
voltmeter reading is shown in Fig. 2.3. Record the voltmeter reading in Table 2.1
for l = 20.0 cm.
[1]
(c) The student repeats the procedure using values of l = 40.0 cm, 60.0 cm, 80.0
cm and 100.0 cm. The readings are shown in Table 2.1.
Complete the column headings in the table.
[1]
8
Table 2.1
(d) Plot a graph of V / V (y-axis) against l / cm (x-axis). Start both axes at the origin
(0, 0).
[4]
9
(e) Determine the gradient G of the graph. Show clearly on the graph how you
obtained the necessary information.
G = ........................................................ [2]
(f) Calculate the resistance R of each centimetre of the wire. Use the equation:
𝑹=
𝑮𝒌
𝑰
where k = 1.0 V / cm and where I is the current recorded in (a).
R = ........................................................ [1]
[Total: 10]
10