# The area of the coil in a moving coil galvanometer is 16 cm^2 and has 20 turns. The magnetic induction is 0.2 T…

Q: The area of the coil in a moving coil galvanometer is 16 cm2 and has 20 turns. The magnetic induction is 0.2 T and the couple per unit twist of the suspended wire is 10-6 Nm per degree. If the deflection is 45° calculate the current passing through it

Sol: Given, A = 16 cm2 = 16 × 10-4 m2

B = 0.2 T ; N = 20 , K = 10-6 Nm/degree

θ = 45°

From, K  θ = N i A B

$\large i = \frac{K \theta}{N B A}$

$\large i = \frac{10^{-6} \times 45}{20 \times 0.2 \times 16 \times 10^{-4} }$