Question

The reading of voltmeter in the circuit shown is

• A. 2.25 V
• B. 3.25 V
• C. 4.25V
• D. 6.25V

Answer 1

Answer: (A)

$60\Omega$ resistance and resistance of voltmeter $40\Omega$ are in parallel.
$\therefore$ Their effective resistance
$R_1=\frac{60\times 40}{60+40}=24\Omega$
$\therefore$ Total resistance of circuit
$R_t=24+40=64\Omega$
Current in main circuit
$i=\frac{V}{R_t}=\frac{6}{64}=\frac{3}{32}amp$
$\therefore$ Potential difference across $60\Omega$ read by voltmeter,
$V=i{R}_1=\frac{3}{32}\times 24$
$=2.25volt$