Question

In the figure shown, an ammeter A and a resistor of 4 Ω are connected to the terminals of the source. The emf of the source is 12 V having an internal resistance of 2 Ω. Calculate the voltmeter and ammeter readings.

Answer 1

Given: emf E = 12 V

Internal resistance r = 2 Ω 

External resistance r = 4 Ω 

Ammeter Reading,

\(I=\frac{E}{R+r}=\frac{12}{4+2}=\frac{12}{6}\)

∴ I = 2 A

Voltmeter Reading,

V = E – Ir = 12 – (2 × 2)

∴ V = 8 V