Pearson Edexcel International GCSE
Physics — Topic 2 Paper 3
Electricity · specification 2.1–2.21
Time allowed: 30 minutes
Total marks: 25
Candidate name:
Centre / class:
Answer all questions. You may use a calculator. Show your working. Standard fuse ratings are $3\,\text{A}$, $5\,\text{A}$ and $13\,\text{A}$.
1
An $8.0\,\text{V}$ battery is connected to resistor X of $5.0\,\Omega$ and resistor Y of $15\,\Omega$ in series. Two garden lamps in a house are later discussed as a parallel application.
(a) Calculate the current in the series circuit.
[2]
(b) Calculate the voltage across resistor Y.
[2]
(c) Explain one advantage of wiring two garden lamps in parallel rather than in series.
[2]
(Total for Question 1 = 6 marks)
2
A toaster is labelled $230\,\text{V}$, $805\,\text{W}$. It is double insulated.
(a) Calculate the current in the toaster when it is used on the mains.
[2]
(b) Choose the most appropriate fuse. Explain why the toaster does not need an earth wire.
[2]
(c) The toaster is used for $4.0\,\text{minutes}$. Calculate the energy transferred.
[2]
(Total for Question 2 = 6 marks)
3
A student compares the I–V characteristic of a fixed resistor with that of a diode.
(a) Describe how the student should change the voltage and record a set of results for each component.
[3]
(b) The table shows results for the diode.
| Voltage / V | $-2.0$ | $0$ | $0.40$ | $0.70$ | $0.80$ |
|---|---|---|---|---|---|
| Current / A | $0.00$ | $0.00$ | $0.00$ | $0.12$ | $0.28$ |
(i) Calculate the resistance of the diode at $0.70\,\text{V}$.
[2]
(ii) Use the table to explain why a diode is not an ohmic conductor.
[2]
(Total for Question 3 = 7 marks)
4
A security light uses an LDR. When it is dark the LDR has a high resistance.
(a) State what happens to the resistance of the LDR at dawn, as the garden becomes brighter.
[1]
(b) The LDR is in series with a $12\,\text{V}$ battery. Explain what happens to the current in this series circuit as dawn arrives.
[2]
(c) Later, $6.0\,\text{C}$ of charge passes through a lamp connected to the $12\,\text{V}$ battery. Calculate the energy transferred to the lamp.
[3]
(Total for Question 4 = 6 marks)
END OF PAPER 3