Q.

A big circular coil of 1000 turns and average radius 10 m is rotating about its horizontal diameter at 2 rad s-1. If the vertical component of earth’s magnetic field at that place is 2×10-5T and electrical resistance of the coil is 12.56Ω, then the maximum induced current in the coil will be          [2022]

1 0.25 A  
2 1.5 A  
3 1 A  
4 2 A  

Ans.

(3)

Given, number of turns (N)=1000

Radius (r)=10 m

Angular velocity (ω)=2 rad s-1

Magnetic field (B)=2×10-5T

Electrical resistance (R)=12.56Ω

Maximum induced emf =NωAB

Here area of the circular coil A=πr2

ε=Nωπr2B=1000×2×3.14×(10)2×2×10-5

ε=12.56V

The maximum induced current is, imax=εR

imax=12.5612.56=1 A