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Year 9 Electricity Test
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TOTAL MARKS /52
Section A: Multiple Choice Questions (out of 13 marks)
1. The device used to measure electric current is: (1 mark)
A amperes
B voltmeter
C ohmeter
D ammeter
2. A transformer: (1 mark)
A
B
C
increases or decreases voltage
is a safety device that cuts the current if too much is flowing
transforms voltage into current
D is a power pack
3. Which of the following materials is an insulator? (1 mark)
A copper
B rubber
C nichrome
D aluminium
4. A charged particle has 35 protons, 38 neutrons and 34 electrons. What would be
the overall charge of the particle? (1 mark)
A +1
B -1
C +3
D -3
5. Two light globes are attached in parallel with a battery. Another light globe is
attached in parallel to the first two. What would happen to the brightness of the
first two globes? (1 mark)
A They get duller.
B They get brighter.
C They stay the same brightness.
D They would all ‘blow’.
6. Which of the following represents Ohm’s Law? (1 mark)
A R=IXV
B R = V/I
C V = I/R
D I=RXV
7. The resistance of a wire does NOT depend on the: (1 mark)
A type of material the wire is made from
B length
C thickness of the wire
D voltage applied across the wire
8. What would be the resistance of a wire that carries 6A when 12V is applied across
it? (1 mark)
A
2 ohms
B
24 ohms
C
0.5 ohms
D
1 ohms
9. If the voltage is held constant, what happens to the current when resistance is
increased? (1 mark)
A
Increases
B
Decreases
C
Stays the same
D
Not enough information to decide
10. The earth wire is most commonly coloured: (1 mark)
A Blue
B Red
B Brown
D Green/yellow
Use the following information to answer questions 11, 12 and 13 below.
A light globe was connected into the circuit below. The current passing through it
was measured as the voltage of the power pack was increased.
The results of the experiment are shown in the graph below.
11. State the approximate current flowing through the globe when 2.5 V is applied
across it. (1 mark)
A 0.02 A
B 2A
C 0.025 A
D 0.005 A
12. The current was not measured when the voltage was zero. Use the graph to
predict the current when the battery is disconnected. (1 mark)
A 0A
B 0.002 A
C 0.004 A
D 0.005 A
13. The resistance of the graph can be predicted from the slope of the graph. The
steeper the graph, the higher the resistance of the light globe. Use the graph
to determine which of the following statements is most accurate. (1 mark)
A
B
C
D
Resistance is constant.
Resistance increases as voltage increases.
Resistance decreases as voltage increases.
Resistance is zero because the wire in a light globe is a conductor.
Section B: Short Answer Questions (out of 41 marks)
1. Describe one difference between static electricity and current electricity.
(2 marks)
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2. Specify the unit and unit symbol used to measure: (6 marks)
a current
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b voltage
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c resistance
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3. Calculate the supply voltage of the battery arrangement shown below. (1
mark)
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4. List three advantages that parallel circuits have over series circuits. (3 marks)
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5. Explain what is meant by electrical resistance. (1 mark)
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6. Draw a circuit consisting of a dry cell, a closed switch and two light globes in
series. Indicate the flow of electrons and if the light bulbs will glow. (3 marks)
7. List and describe two different electrical safety devices and how they can
break a circuit when an abnormally high current is detected. (4 marks)
Device 1:
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Device 2:
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8. List three things needed before a current will flow in a circuit. (3 marks)
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9. Use the following diagram to answer part a, b, c, d, and e of question 9.
24 V
A
B
D
C
E
F
(a) On the diagram above indicate the voltage of each light globe. (6 marks)
(b) On the diagram above, clearly mark an ‘X’ where a switch could be placed
that would only turn off light globes B and C. (1 mark)
(c) Describe the differences in the brightness of the globes in the diagram
above. (3 marks)
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(d) Describe what would happen to all other light globes if globe F blew.
(3 marks)
Globe A:
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Globe B:
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Globe C:
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Globe D:
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Globe E:
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Globe F:
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(e) Globe F was then replaced so that all globes in the circuit above were
once again working. Soon after, globe C broke and stopped glowing.
Which of the other globes would also stop glowing because of this? (1
mark)
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10. Provide an advantage and disadvantage of using wet cells. (2 marks)
Advantage:
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Disadvantage:
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