Question

A moving coil galvanometer has a rectangular wire coil of enclosed area $0.001 \,m ^{2}$ and $500$ turns. The coil operates in a radial magnetic field of $0.2 \,T$ and carries a current of $6 \,\pi \times 10^{-8} A$. If the torsional spring constant is $6 \times 10^{-7} \,N - m / rad$, then the angular deflection of the coil in radians is

• A. $\frac{\pi}{100}$
• B. $\frac{\pi}{200}$
• C. $\frac{\pi}{300}$
• D. $\frac{\pi}{400}$

Answer 1

Answer: (A)

Angular deflection of a moving coil galvanometer is given by
$\theta =\left(\frac{N B A}{k}\right) i $
$=\frac{500 \times 0.2 \times 0.001}{6 \times 10^{-7}} \times 6 \pi \times 10^{-8} $
$=\frac{5 \times 0.2 \times 10^{-1} \times 6 \pi \times 10^{-8}}{6 \times 10^{-7}}$
$\theta =\frac{\pi}{100}$