Question

In the circuit shown in the figure, the reading of the voltmeter $V$ will be

• A. $4\text{V}$
• B. $2\text{V}$
• C. $6\text{V}$
• D. $3\text{V}$

Answer 1

The correct option is A $4\text{V}$

The voltmeter measures the potential difference across $100\Omega$ resistor. Let $i$ be the current through the circuit.

$i=\frac{12}{100+200}=0.04\text{A}$

Potential difference across $100\Omega$ resistor, $\Delta V=iR=0.04\times 100=4\text{V}$

$\text{Note:}$ In an ideal voltmeter, the resistance is infinite, here, $i_V=0$.