Question

A voltmeter having a resistance of $998\Omega$ is connected to a cell of emf $2$V and internal resistance $2\Omega$. The error in the measurement of emf will be.

• A. $4\times {10}^{-1}$V
• B. $2\times {10}^{-3}$V
• C. $4\times {10}^{-3}$V
• D. $2\times {10}^{-1}$V

Answer 1

Answer: (C)

$4\times {10}^{-3}$V

$I=\frac{2}{99}=\frac{2}{1000}=2\times {10}^{-3}$A
$=2$mA
Internal resistance is $2\Omega$
Hence, the measure of emf will be
$E=2-I\times 2$
$=2-2mA\times 2$
Therefore, error in measured value $=4\times {10}^{-3}$V.