Question

A galvanometer coil bas 500 turns and each tum has an average area of 3 × 10^-4 m². If a torque of 1.5 Nm is required to keep this coil parallel to a magnetic field when a current of 0.5 A is flowing through it, the strength of the field (in T) is ______.

Options

• 10

• 20

• 30

• 40

Answer 1

A galvanometer coil bas 500 turns and each tum has an average area of 3 × 10^-4 m². If a torque of 1.5 Nm is required to keep this coil parallel to a magnetic field when a current of 0.5 A is flowing through it, the strength of the field (in T) is 20.

Explanation:

Given,

Area of galvanometer coil, A = 3 × 10^-4 m²

Number of turns in the coil, N = 500

Current the coil, I = 0.5 A

Torque τ = `|vec"M"xxvec"B"|` = NiAB sin (90°) = NiAB

⇒ B = `τ/("NiA")`

= `1.5/(500xx0.5xx3xx10^-4)`

= 20 T