Free Circuit components questions for IGCSE Physics (0625), part of Electricity & magnetism. Each question has the answer and the marking points an examiner would look for.
Generate a full Circuit Components worksheet →All Electricity & magnetism questionsA thermistor and a fixed resistor are connected in series with a 6.0 V battery. A voltmeter is connected across the fixed resistor.
The temperature of the thermistor rises.
What happens to the resistance of the thermistor and to the reading on the voltmeter?
| resistance | voltmeter reading | |
|---|---|---|
| A | decreases | increases |
| B | decreases | decreases |
| C | increases | increases |
| D | increases | decreases |
Answer: A
A 3.0 kΩ resistor and a 12.0 kΩ resistor are connected in series to a 6.0 V supply of negligible resistance.
What is the potential difference across the 3.0 kΩ resistor?
Answer: A
Which term is described by this statement?
“A component whose resistance decreases as light intensity increases.”
Answer: B
A thermistor and a fixed resistor of 2000 Ω are connected in series to a 6.0 V supply of negligible internal resistance. A voltmeter is connected across the thermistor. At 20 °C the thermistor has a resistance of 1500 Ω. At 60 °C its resistance is 500 Ω.
Draw a circuit diagram of the arrangement.
Calculate the reading on the voltmeter at 20 °C.
Calculate the reading on the voltmeter at 60 °C.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | supply, fixed resistor and thermistor in series; voltmeter in parallel with thermistor series circuit with correct thermistor symbol B1 voltmeter in parallel with the thermistor B1 | 2 |
| (b) | 2.57 V total resistance = 3500 Ω C1 I = 6/3500 = 1.71 × 10−3 A C1 V = IR = 2.57 V A1 | 3 |
| (c) | 1.20 V V = 6 × 500/2500 C1 1.20 V A1 | 2 |
Fig. 5.1 shows a potential divider made from a fixed resistor of 2000 Ω and component T connected in series to a 6.0 V supply. The voltmeter measures the output, the p.d. across T.
Name component T.
State how the resistance of an NTC thermistor changes as its temperature increases.
At a certain temperature the thermistor has resistance 1000 Ω. Calculate the output p.d.
The temperature rises. Explain what happens to the output p.d.
Describe how the resistance of a light-dependent resistor changes with light intensity, and give one use.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | thermistor thermistor B1 | 1 |
| (b) | decreases decreases B1 | 1 |
| (c) | 2.00 V total resistance = 3000 Ω C1 current = 2.00 × 10−3 A or ratio 1000/3000 C1 2.00 V A1 | 3 |
| (d) | decreases: thermistor resistance falls, takes a smaller share of p.d. thermistor resistance decreases B1 so it has a smaller share of the supply p.d. and the output decreases B1 | 2 |
| (e) | resistance decreases as light increases; automatic street lights resistance decreases as light intensity increases B1 use: automatic night lights / street lights B1 | 2 |
A fuse is used in many electrical appliances.
Explain how a fuse protects an appliance.
An appliance uses a current of 3.5 A. Fuses rated 3 A, 5 A and 13 A are available. State which should be used and why.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | melts if current too large, breaking circuit if the current is too large, the fuse wire overheats and melts B1 this breaks the circuit B1 | 2 |
| (b) | 5 A 5 A B1 it is just above the normal working current B1 | 2 |
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Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in