A coil of turns and area rotates with constant angular speed in a uniform magnetic…

PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

A coil of

50

turns and area

0.015\,\text{m}^2

rotates with constant angular speed

100\,\text{rad s}^{-1}

in a uniform magnetic field of

0.25\,\text{T}

. At

t=0

, the plane of the coil makes an angle of

30^{\circ}

with the magnetic field. The earliest time

t>0

at which the induced emf becomes zero is: (a)

52\,\text{ms}

(b)

31\,\text{ms}

(c)

26\,\text{ms}

(d)

21\,\text{ms}