ELECTRICAL RESISTANCE

3 marks · Normal

The diagram below shows a circuit with a battery and two resistors connected in series.

Series circuit with two resistors

(a)

Calculate the total resistance in the circuit.

[1 mark]

(b)

Calculate the current in the circuit. Show your working.

[2 marks]

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

Show answer

(a) 14 \; \Omega ohm

(b) 0.86 \; \mathrm{A} A

Common mistakes: Adding resistors incorrectly; Incorrectly using V=IR

Show mark scheme and worked solution

Marking points

B1 (a) · 1 mark · Correctly adds resistances in series to get total resistance.

M1 (b) · 1 mark · Uses I = V / R with correct or follow-through R. (follow-through)

A1 (b) · 1 mark · Correct calculation of I with unit. (follow-through)

Worked solution

a) Total resistance = 8 Ω + 6 Ω = 14 Ω

b) I = V / R = 12 V / 14 Ω = 0.857 A (or 0.86 A to 2 dp)