Pearson Edexcel International GCSE in Physics · 4PH1 · Free · no account needed
Current–Voltage Graphs, LDRs and Thermistors — exam questions
12 original Incandio exam-style questions on Current–Voltage Graphs, LDRs and Thermistors, 27 marks, about 27 minutes of writing. Each one carries the command word, the tariff and the specification statement it assesses, exactly as a paper presents them. This is an original Incandio practice question, written to reflect the structure and demands of the qualification. It is not an official Pearson Edexcel past-paper question.
This is the practice set for Current–Voltage Graphs, LDRs and Thermistors — the lesson that teaches it. Read the lesson first if the idea is new; come here when you want to find out whether you can turn it into marks. Completely free, no account needed to read.
What these questions ask of you
8 command words run through this set, and on Pearson Edexcel International GCSE Physics each one means something precise. Answering the wrong command is the commonest way a candidate who understands the lesson still loses the mark.
- Which (1 mark)
- one option chosen from the set given
- State (1 mark)
- one precise fact or definition
- Describe (2–4 marks)
- developed, linked statements of what happens — including a named direction where one exists
- Explain (2–4 marks)
- the physics that causes it, set out as a line of reasoning Misread as: describing the change without giving the physical reason for it
- Determine (1–4 marks)
- a value obtained by combining a reading or gradient with a relationship
- Give (1–2 marks)
- a short factual answer
- Calculate (1–5 marks)
- select the equation, substitute, evaluate — and state the unit Misread as: giving a bare number with no equation and no unit
- Suggest (1–3 marks)
- a plausible answer applying taught physics to an unfamiliar arrangement
Assessed on Paper 1 (4PH1/1P) and Paper 2 (4PH1/2P), against AO1, AO2, AO3.
Where these sit in the specification
Pearson Edexcel International GCSE Physics (4PH1) — statements 2.12 · 2.11 · 2.9. Incandio is aligned to this specification; it is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording.
The 12 questions
Answer them on paper, then open the lesson's exam practice to have them marked. The mark scheme, the accepted and rejected answers and the annotated model answer are in Incandio and are not printed here — an answer beside its question is not practice.
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Table 1 — current through a filament lamp at different voltages Voltage / V Current / A 1.0 0.25 2.0 0.40 3.0 0.50 4.0 0.57 5.0 0.62 (a)
(1)Give
Give the current through the lamp at 2.0 V, using Table 1.
Table 1 — current through a filament lamp at different voltages Voltage / V Current / A 1.0 0.25 2.0 0.40 3.0 0.50 4.0 0.57 5.0 0.62 current through the lamp = ............................ A
(b)
(3)Calculate
Calculate the resistance of the lamp at 1.0 V and at 5.0 V, using Table 1.
Table 1 — current through a filament lamp at different voltages Voltage / V Current / A 1.0 0.25 2.0 0.40 3.0 0.50 4.0 0.57 5.0 0.62 (c)
(2)Explain
Explain what your two answers to part (b) show about the lamp.
Table 1 — current through a filament lamp at different voltages Voltage / V Current / A 1.0 0.25 2.0 0.40 3.0 0.50 4.0 0.57 5.0 0.62 (d)
(3)Suggest
Suggest how the student could obtain readings for the lamp with the current flowing the opposite way, and what Table 1 would then look like.
Table 1 — current through a filament lamp at different voltages Voltage / V Current / A 1.0 0.25 2.0 0.40 3.0 0.50 4.0 0.57 5.0 0.62 (Total for Question 1 = 9 marks)
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(1)Which
Which component only allows current to pass in one direction?
Component A a fixed resistor B a filament lamp C a diode D a thermistor (Total for Question 2 = 1 mark)
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(1)State
State what happens to the resistance of a light-dependent resistor as the light falling on it gets brighter.
(Total for Question 3 = 1 mark)
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(1)State
State what happens to the resistance of a thermistor as its temperature rises.
(Total for Question 4 = 1 mark)
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(2)Describe
Describe the shape of the current–voltage graph for a fixed resistor kept at constant temperature.
(Total for Question 5 = 2 marks)
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(3)Explain
Explain why the current–voltage graph for a filament lamp is a curve rather than a straight line.
(Total for Question 6 = 3 marks)
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(3)Explain
Explain how an LDR can be used to switch a street lamp on automatically at dusk.
(Total for Question 7 = 3 marks)
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(3)Determine
Determine the resistance of the thermistor in Figure 1 at 25 °C, and describe how it changes across the range shown.
Figure 1 — resistance of a thermistor against temperature. Plotted as a line; the graph is drawn in Incandio and the readings are below. Temperature / °C Resistance / Ω 0 2000 10 1300 20 900 30 600 40 420 50 300 (Total for Question 8 = 3 marks)
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(4)Explain
Explain why the current–voltage graph for a filament lamp curves, while the graph for a fixed resistor at constant temperature is a straight line.
(Total for Question 9 = 4 marks)
Have them marked, then defend the answer
Practice tells you the mark; teaching it back tells you whether you understand it. On Incandio a topic counts as mastered only once you have taught it and defended it.
- Mark these questions — 12 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain Current–Voltage Graphs, LDRs and Thermistors to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Humphry Davy over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Current–Voltage Graphs, LDRs and Thermistors — The shapes four components make on a graph, and two resistors that deliberately refuse to stay the same.
- All of Incandio Physics · Incandio Exam Practice