A copper disc of radius 0.1 m is rotated about its centre with 10 rev / s in a uniform magnetic field of 0.1 T with its plane perpendicular to field. The emf induced across the radius of disc is

Question

A copper disc of radius 0.1 m is rotated about its centre with 10 rev / s in a uniform magnetic field of 0.1 T with its plane perpendicular to field. The emf induced across the radius of disc is (A) (π/10) volt (B) (π/100) volt (C) (π/1000) volt (D) Zero

Tardigrade Admin · Accepted Answer

ε=(1/2) B ω R2, R=0.1 m , B=0.1 T , W=20 (π/ s ) ε=(1/2)(0.1)(0.1)2(20 π) =(π/100) volt

Q. A copper disc of radius $0.1 m$ is rotated about its centre with $10 re v / s$ in a uniform magnetic field of $0.1 T$ with its plane perpendicular to field. The emf induced across the radius of disc is

$\frac{π}{10}$ volt

$\frac{π}{100}$ volt

$\frac{π}{1000}$ volt

Zero

$ε = \frac{1}{2} B ω R^{2},$
$R = 0.1 m,$
$B = 0.1 T,$
$W = 20 \frac{π}{s}$
$ε = \frac{1}{2} (0.1) (0.1)^{2} (20 π)$
$= \frac{π}{100}$ volt

Q. A copper disc of radius 0.1m is rotated about its centre with 10rev/s in a uniform magnetic field of 0.1T with its plane perpendicular to field. The emf induced across the radius of disc is

10π​ volt

100π​ volt

1000π​ volt