Lesson 3.4.1

3.4.1 Potential gradient and potential divider circuits Quiz: Pearson Edexcel Physics, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.4.1, Potential gradient and potential divider circuits: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 3: Electric Circuits, written with Revision Ninja.

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The 20 questions

  1. What is the potential gradient along a uniform wire carrying a steady current?

    • Current per unit cross-sectional area of the wire, in A/m^2
    • Potential difference per unit length along the wire, in V/m
    • Charge passing a point on the wire per unit time, in C/s
    • Resistance per unit length of the wire, in ohm/m

  2. Two resistors R1 and R2 are in series across a supply of p.d. V. What is the p.d. across R2?

    • V R1/(R1 + R2)
    • V R2/R1
    • V R2/(R1 + R2)
    • V (R1 + R2)/R2

  3. What is the main purpose of a potential divider in a sensing circuit?

    • To increase the total current drawn from a cell above its e.m.f.
    • To store charge and release it as a short pulse
    • To give an output p.d. that changes when a sensor's resistance changes
    • To convert alternating current into direct current

  4. In a divider with an NTC thermistor as R1 and a fixed resistor R2, what happens to the output p.d. across R2 as temperature rises?

    • It stays constant, because the supply p.d. is fixed
    • It increases, because the thermistor resistance falls and R2 takes a larger share of the supply p.d.
    • It decreases, because the thermistor resistance rises and R2 takes a smaller share of the supply p.d.
    • It decreases, because the thermistor resistance falls and R2 takes a smaller share of the supply p.d.

  5. A load is connected in parallel with R2 in a potential divider. Why is the load resistance usually made much greater than R2?

    • So the load resistance cancels the internal resistance of the cell
    • So the load draws more current from the supply than R2 does
    • So the p.d. across the load is larger than the supply p.d.
    • So the combined resistance stays close to R2 and the output p.d. stays close to its unloaded value

  6. A 2.0 m uniform wire has a p.d. of 6.0 V across its ends. What is its potential gradient?

    • 4.0 V/m
    • 12 V/m
    • 0.33 V/m
    • 3.0 V/m

  7. In a potential divider with no load, if R2 is much larger than R1, what is the output p.d. across R2 approximately?

    • The full supply p.d.
    • Zero volts
    • The product of current and R1
    • Half the supply p.d.

  8. A 4.0 ohm wire of length 2.0 m carries a current of 0.50 A. What is its potential gradient?

    • 4.0 V/m
    • 2.0 V/m
    • 1.0 V/m
    • 0.25 V/m

  9. A potential divider has R1 = 300 ohm and R2 = 100 ohm across a 12 V supply. What is the p.d. across R2?

    • 3.0 V
    • 9.0 V
    • 4.0 V
    • 1.5 V

  10. A 6.0 V supply is across a 2.0 kohm fixed resistor R1 in series with an LDR R2 of 4.0 kohm. What is the output p.d. across the LDR?

    • 6.0 V
    • 3.0 V
    • 2.0 V
    • 4.0 V

  11. Two 100 ohm resistors are in series across 10 V. A voltmeter of resistance 100 ohm is connected across one of them. What does it read?

    • 3.3 V
    • 10 V
    • 2.5 V
    • 5.0 V

  12. A divider has a fixed R1 of 12 ohm across a 9.0 V supply, and the output across R2 is 3.0 V. What is R2?

    • 18 ohm
    • 4.0 ohm
    • 6.0 ohm
    • 12 ohm

  13. A 1.0 m uniform wire is connected across 10.0 V. How far from the 0 V end is the point at which the potential is 2.0 V?

    • 0.20 m
    • 0.80 m
    • 2.0 m
    • 0.50 m

  14. A wire has a p.d. of 1.5 V across 0.30 m. What is the p.d. between two points 0.12 m apart on the wire?

    • 0.15 V
    • 1.2 V
    • 0.60 V
    • 0.36 V

  15. Which arrangement gives an output that varies smoothly from 0 to the full 6 V supply?

    • A variable resistor used only as a current limiter in series with the supply, output across the supply terminals
    • Two fixed resistors in parallel across the supply, with output across one of them
    • A variable resistor with its two fixed ends across the supply and the output taken from the slider
    • A single fixed resistor across the supply with an ammeter in series

  16. A potential divider has R1 = 100 ohm and R2 = 100 ohm across 6.0 V. A 100 ohm load is connected across R2. What is the output p.d. across the load?

    • 2.4 V
    • 2.0 V
    • 3.0 V
    • 1.5 V

  17. Two resistors R1 and R2 are in series across V. The p.d. across R2 is V2. Which expression gives R1?

    • R1 = R2 V2/(V - V2)
    • R1 = R2(V - V2)/V2
    • R1 = R2(V + V2)/V2
    • R1 = V2(V - R2)/R2

  18. Resistors of 2.0 kohm, 3.0 kohm and 5.0 kohm are in series across 10 V. What is the p.d. across the 3.0 kohm and 5.0 kohm resistors together?

    • 8.0 V
    • 3.0 V
    • 6.0 V
    • 5.0 V

  19. Why does a uniform current-carrying wire give a linear potential gradient?

    • Its current increases steadily along its length
    • Its resistance per unit length is constant, so the p.d. per unit length is the same everywhere along it
    • Its resistance decreases steadily with distance along it
    • Its electrons gain energy from the cell at a steady rate along its length

  20. Why is the output of a thermistor potential divider not directly proportional to temperature?

    • The supply p.d. falls as the temperature of the thermistor rises
    • Potential dividers always give an output that is directly proportional to resistance
    • Thermistor resistance changes non-linearly with temperature, so its share of the supply p.d. does not change linearly
    • Thermistors obey Ohm's law only above their maximum operating temperature

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