Question

A voltmeter of $998$ ohm resistance is connected to a cell of emf $2$ volt, having internal resistance of $2$ ohms, The error in measuring 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)

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

Current in circuit is $i=\frac{2}{998+2}=1/500A$

Error in measuring $=$potential across internal resistance $=\left(1/500\right)\left(2\right)=0.004=4\times {10}^{-3}V$