Magnetic Effects Of Current Question 2

Question 2 - 2024 (01 Feb Shift 2)

A moving coil galvanometer has 100 turns and each turn has an area of $2.0 cm^{2}$. The magnetic field produced by the magnet is $0.01 T$ and the deflection in the coil is 0.05 radian when a current of $10 mA$ is passed through it. The torsional constant of the suspension wire is $x \times 10^{-5} N-m / rad$. The value of $x$ is

Show Answer

Answer: (4)

Solution:

$\tau=$ BINAsin

$C \theta=$ BINAsin $90^{\circ}$

$C=\frac{\text { BINA }}{\theta}=\frac{0.01 \times 10 \times 10^{-3} \times 100 \times 2 \times 10^{-4}}{0.05}$

$=4 \times 10^{-5} N-m / rad$.

$x=4$