Question

A closely wound circular coil of radius 0.02 m is placed perpendicular to the magnetic field. When the magnetic field is changed from 8000 T to 2000 T in 6 s, an emf of 44 V is induced in it. Calculate the number of turns in the coil.

Answer 1

Given data:

radius r = 0.02 m

Q = 90° – 90° = 0°

B₁ = 8000 T, B₂ = 2000 T

dt = 68

ε = 68V

n = ?

ε = nA cos θ `"dB"/"dt"`

`44 = "n" xx pi xx 0.02 xx 0.02 xx cos theta xx ((8000 - 2000)/6)`

`44 = "n" xx 22/7 xx 4 xx 10^4 xx 1 xx 6000/6`

n = `(44 xx 7 xx 6)/(22 xx 4 xx 10^-4 xx 6000)`

`= 7/(2 xx 10^-1) = 70/2`

n = 35 turns