Exam code: 1SC0
Alternating current is the movement of charge
up and down.
in many directions.
in one direction.
backwards and forwards.
State an electrical device or component that provides direct current.
Describe the difference between direct and alternating current.
Which row about the UK domestic supply is correct?
| Type of Current | Frequency (Hz) | Voltage (V) |
A | A.C | 50 | 230 |
B | A.C | 230 | 50 |
C | D.C | 50 | 230 |
D | D.C | 230 | 50 |
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State a device that produces A.C.
Explain the purpose of the neutral mains input wire.
What colour is the insulating cable of the live wire in a UK plug?
blue
green and yellow stripes
brown
red
State the potential difference of the
i) earth wire,
[1]
ii) live wire,
[1]
iii) neutral wire.
[1]
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State the function of the earth wire in a UK plug.
A fuse is commonly used to ensure it is safe to use a circuit.
Explain how a fuse ensures the circuit is safe to use.
Explain why it is dangerous to provide any connection between the live and earth wires.
Explain why switches and fuses should be connected in the live wire of a domestic circuit.
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Explain what is meant by the term A.C.
Figure 1 shows a kettle. The kettle uses A.C. current to heat water.
Figure 1
The kettle has a metal case.
Explain why it would be dangerous for the live wire from the electric cable to touch the case of the kettle.
The kettle uses mains power to function.
(i) State the potential difference of the UK main supply.
[1]
(ii) A label on the kettle says that its power output is 2.5 kW.
Show that the current in the kettle is about 11 A.
[2]
(i) State the relationship between voltage, current and resistance.
[1]
(ii) Calculate the resistance of the kettle.
resistance .......................................... Ω[2]
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Figure 1 shows an incomplete table of the insulating cable colours for the wires in a UK plug.
Complete the table by filling in the missing information.
Colour of insulating cable | Name of wire |
|---|---|
Blue |
|
Brown |
|
Red |
|
Yellow and green stripes |
|
Figure 1
An electric lamp contains a 3 A fuse.
Explain the role of the fuse within the circuit of the lamp.
Which of the diagrams shows a fuse which has been correctly connected to the circuit?
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|
 |  |
|
|
 |  |
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A battery-powered lawn mower uses direct current.
Which graph correctly shows direct current?
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|
 |  |
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 |  |
Electric lawnmowers are powered by the mains supply. An electric lawnmower is fitted with a 5 A fuse.
Which row of the table correctly describes where the fuse should be fitted and how the fuse does its job?
| Where is it positioned? | What does it do? |
|---|---|---|
A | live wire | reduces the current to 5 A |
B | neutral wire | breaks the circuit |
C | live wire | breaks the circuit |
D | neutral wire | reduces the current to 5 A |
The owner of an electric lawnmower wants to install a circuit breaker to protect themself and the lawnmower from a surge in current.
Under normal operating conditions, the lawnmower draws a current of 4 A.
The manufacturer provides the graph shown in Figure 1 with the purchase of the circuit breaker.
Figure 1
Which row of the table correctly describes what will happen when the current is 4 A, and what will happen if the current rises to 14 A?
| 4 A | 14 A |
|---|---|---|
A | circuit does not break | circuit does not break |
B | circuit does not break | circuit breaks quickly |
C | circuit breaks quickly | circuit does not break |
D | circuit breaks quickly | circuit breaks quickly |
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Sam has a toaster and the fuse blows. Sam takes the fuse out and sees that it has 13 A written on it.
Sam doesn't have any 13 A fuses, but they have a 3 A fuse and decide to use that.
Describe what will happen when Sam switches on the toaster.
Sam buys a 13 A fuse for the toaster.
Figure 1 shows the possible positions to place the fuse in the circuit.
Figure 1
Which fuses show the correct position for the fuse?
Fuse X and Fuse Y
Fuse X only
Fuse Z only
Fuse X and Fuse Z
As well as a fuse, the toaster is fitted with an earth wire as a safety feature.
Explain how the earth wire makes the toaster safe to use.
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Which of the following shows an A.C. circuit?
Which graph correctly shows an alternating current?
Figure 1 shows a circuit diagram for a D.C. circuit. The circuit contains a fuse.
Figure 1
Each of the ammeters reads 1.2 A.
Which option correctly describes the fuse that should be fitted to the circuit in this position?
1.0 A
3.0 A
5.0 A
13.0 A
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A