CURRENT ELECTRICITY EXERCISE
Section A: Multiple Choice (21 Marks)
1. There is an electric current in the circuit shown.
Which two changes will each increase the current?
2. The charger for a laptop computer is connected by a cable to the mains supply through
a plug.
The plug contains a 13 A fuse. The thin wires in the cable are designed to carry a
current of 2 A.
A fault develops and the current in the wires rises to 5 A.
What is the danger caused by this larger current?
A. A large amount of electrical energy could be wasted.
B. Somebody might receive an electric shock.
C. The fuse could blow and start a fire.
D. The wires could overheat and start a fire.
3. The circuit shown contains four labelled switches. All the switches are closed.
Which switch can be opened without changing the brightness of either bulb?
4. A student wishes to measure the potential difference across a resistor. The circuits
show two different positions in which a meter can be connected.
What meter is used, and where is it connected in the circuit?
A. an ammeter in position X
B. an ammeter in position Y
C. a voltmeter in position X
D. a voltmeter in position Y
5. A circuit contains two lamps and a variable resistor.
The resistance of the variable resistor is increased.
What happens to the brightness of lamp 1 and what happens to the brightness of lamp
2?
SECTION B: STRUCTURED QUESTIONS
6. (a) The diagram shows a bicycle with two lights A and B at the front.
The diagram below shows the circuit used to power the two lights.
(i) State the name given to this type of circuit arrangement.
................................................................................................................. [1]
(ii) To calculate the resistance of light A, the current flowing through it and the voltage
across it must be measured.
On the circuit, using the correct symbols, draw an ammeter and a voltmeter correctly
connected to make these measurements.
[4]
7. The diagram shows a circuit used to measure the current passing through a resistor
when the voltage across it is changed.
The diagram below shows the circuit symbols for an electric bell and a push-switch.
(a) Describe the purpose of component Z in the circuit.
................................................................................................................. [1]
(b) The meters shown in the circuit give readings of 0.6 A and 8.0 V.
State which meter, X or Y, gives the reading of 0.6 A.
Explain your answer.
Meter……………………………………
Explanation……………………………………………………………………………………………………
…………………………………………………
……………………………………………………………………………………………………………………
…………………………………………… [1]
(c) Use the formula
resistance = potential difference / current to calculate the resistance of the
resistor.
State the units for your answer.
……………………………. Unit = ………………………… [2]
8. (a) Complete the Table below by drawing the circuit symbol for each electrical
component
[2]
(b) The diagram shows an electrical hazard.
State the hazard.
................................................................................................................. ......
...........................................................................................................
Explain why this situation is dangerous.
................................................................................................................. ......
........................................................................................................... [2]
(c) In the circuit shown in the diagram below reading, on ammeter A3 is 0.5 A.
(i) State the current readings on ammeters A1 and A2.
A1 …………………………………A A2 …………………………………A
[1]
(ii) Each lamp in the circuit has a resistance of 5 Ω. Calculate the combined
resistance of the two lamps in the circuit.
State the formula that you use and show your working.
………………………………………….. Ω [2]
