Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Electricity
249 practice questions
Topics covered
Practice questions
241–249 of 249
Question 241
4 marks · Easy
Answer and see the solution →The lamp in a student’s desk light has a voltage of 12 V across it and a current of 0.5 A flowing through it when switched on. The lamp is connected to the mains using a plug that contains a fuse and a live, neutral and earth wire.
(a)[1 mark]Calculate the power output of the lamp.
(b)[1 mark]Name which wire the switch and fuse are always connected to and give a reason.
(c)[1 mark]Explain how the fuse works to protect the appliance.
(d)[1 mark]State one reason double insulation can make the earth wire unnecessary.
Question 242
6 marks · Normal
Answer and see the solution →A lamp is connected to the mains supply in a household circuit. The lamp has a power rating of 60 W and operates at 240 V.
(a)[2 marks]State the SI units for power, voltage, and current.
(b)[2 marks]Calculate the current flowing through the lamp when it is operating at its rated power.
(c)[2 marks]Explain how the use of a fuse in the plug protects the lamp and the user if a fault occurs.
Question 243
5 marks · Normal
Answer and see the solution →A hairdryer is labelled '230 V, 1200 W'.
(a)[2 marks]What do these values mean for the operation of the hairdryer?
(b)[2 marks]Calculate the current drawn by the hairdryer during operation.
(c)[1 mark]The hairdryer casing is made of plastic. Explain why this is important for electrical safety.
Question 244
4 marks · Normal
Answer and see the solution →Figure 1 shows a simple circuit with a 9 V battery connected in series with a fixed resistor (3 Ω) and a bulb (3 Ω).
(a)[1 mark]Calculate the total resistance in the circuit.
(b)[2 marks]Determine the current flowing through the circuit.
(c)[1 mark]State the voltmeter reading if it is connected across the bulb only.
Question 245
5 marks · Normal
Answer and see the solution →A 0.5 m length of wire has a current of 0.4 A flowing through it when a voltage of 2 V is applied across its ends.
(a)[2 marks]Calculate the resistance of the wire.
(b)[2 marks]If the current flows for 3 minutes, calculate the total charge passing through the wire.
(c)[1 mark]Name the unit of electric charge.
Question 246
5 marks · Normal
Answer and see the solution →A kettle is marked '230 V, 1800 W'.
(a)[2 marks]Calculate the current flowing through the kettle.
(b)[2 marks]State and justify which of the following fuses is most appropriate for this kettle: 3 A, 5 A, or 13 A.
(c)[1 mark]Explain the effect of resistance in the heating element of the kettle.
Question 247
5 marks · Normal
Answer and see the solution →1. The diagram below shows a hairdryer connected to the mains supply in a domestic circuit. It contains a heating element and operates at a voltage of 230 V.
(a)[3 marks]State the function of the live, neutral, and earth wires in a mains plug.
(b)[2 marks]Explain why double insulation is important for some appliances such as the hairdryer, and describe how it helps protect the user.
Question 248
5 marks · Normal
Answer and see the solution →2. An electric heater with resistance 46 Ω is connected in series with an ammeter and a 230 V mains supply.
(a)[2 marks]Calculate the current through the heater.
(b)[1 mark]State the SI unit for resistance.
(c)[2 marks]Calculate the energy transferred by the heater in 30 seconds.
Question 249
5 marks · Normal
Answer and see the solution →3. A string of decorative garden lights contains many bulbs connected in parallel to the mains supply. Each bulb is marked '230 V, 15 W'.
(a)[2 marks]Explain why the bulbs are connected in parallel rather than in series.
(b)[2 marks]Calculate the current in a single bulb.
(c)[1 mark]If all 40 bulbs are switched on, calculate the total current drawn from the supply.