The actual value of resistance $R$, shown in the figure is $30 \Omega$. This is measured in an exper

Question

The actual value of resistance $R$, shown in the figure is $30 \Omega$. This is measured in an experiment as shown using the standard formula $R=\frac{V}{I}$, where $V$ and $I$ are the reading of the voltmeter and ammeter, respectively. If the measured value of $R$ is $5 \%$ less, then the internal resistance of the voltmeter is\

Professor PC Thomas Classes · Answer

(a) : $R_{a}=30 \Omega, R_{m}=R_{a}-\frac{5}{100} 	imes R_{a}$ $=0.95 R_{a}$\ As, $0.95 R_{a}=\frac{R_{a} R_{v}}{\left(R_{a}+R_{v}ight)}$\ $0.95 R_{a}+0.95 R_{v}=R_{v} ; 0.95 R_{a}=0.05 R_{v}$\ $R_{v}=19 R_{a}=19 	imes 30=570 \Omega$\