Question

Two resistors are connected in series across a battery as shown in figure. If a voltmeter of resistance $2000\Omega$ is used to measure the potential difference across $500\Omega$ resistor, the reading of the voltmeter will be V

Answer 1

$\text{Total resistance after connecting voltmeter}$
$R_{eff}=\frac{2000\times 500}{2500}+600\Omega =1000\Omega$
$\Rightarrow \text{Reading of voltmeter =}\frac{400}{1000}\times 20=8\text{volts}$