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

Question

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 × 10 - 5 N - m / rad . The value of x is ______ .

TestHub · Accepted Answer

Torque produced in a moving coil galvanometer is, $τ = BINAsin ϕ$ .

Let torsional constant of the suspension wire be $C$ , then $C θ = BINAsin 90 °$

$\Rightarrow C = \frac{B I N A}{θ} = \frac{0.01 \times 10 \times 10^{- 3} \times 100 \times 2 \times 10^{- 4}}{0.05}$

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

Therefore, $x = 4$ .

Physics - Magnetism Question with Solution | TestHub

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