In the circuit shown in figure, ammeter and voltmeter are ideal. If E = 4 V, R = 9Ω and r = 1Ω, then readings of ammeter and voltmeter are

1 A, 3 V

The given three resistors are in parallel.

∴ Current, $\mathrm{i}=\frac{\mathrm{E}}{\mathrm{r}+\mathrm{R} / 3}=\frac{4}{1+3}=1 \mathrm{A}$

$\mathrm{V}=\frac{\mathrm{i}}{3} \mathrm{R}$            or            $\mathrm{E}-\mathrm{ir}=\left(\frac{1}{3}\right)(9)=3 \mathrm{V}$