Question

A galvanometer is used in laboratory for detecting the null point in electrical exoeriments. If, on passing a current of $6\text{mA}$ it produces a deflection of $2^{\circ }$, its figure of merit is close to

• A. ${333}^{\circ }\text{A/div.}$
• B. $6\times {10}^{-3}\text{A/div.}$
• C. ${666}^{\circ }\text{A/div.}$
• D. $3\times {10}^{-3}\text{A/div.}$

Answer 1

The correct option is D $3\times {10}^{-3}\text{A/div.}$

Given,

Current passing through galvanometer, $l=6\text{mA}$
Deflection, $\theta =2^{\circ }$

Figure of merit of galvanometer

$=\frac{l}{\theta }=\frac{6\times {10}^{-3}}{2}=3\times {10}^{-3}\text{A/div.}$