A-LevelPhysicsD.C. circuits9702/12 · Oct/Nov 2011 · Q351 Mark

A power supply of electromotive force (e.m.f.) 12 V and internal resistance 2 Ω is connected in series with a load resistor. The value of the load resistor is varied from 0.5 Ω to 4 Ω. Which graph shows how the power P dissipated in the load resistor varies with the resistance of the load resistor? [Figure 35.1]

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Agraph showing power peaking at load resistance 2 Ω

Bgraph showing power at a minimum at load resistance 2 Ω

Cgraph showing power increasing linearly with load resistance

Dgraph showing power increasing with load resistance, curving upwards

✓ Correct answer

A: graph showing power peaking at load resistance 2 Ω

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Topic: D.C. circuits, A-Level Physics (syllabus 9702). Multiple choice, 1 mark.
Source: A-Level Physics, Oct/Nov 2011 Paper 1 Variant 2, question 35.

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