Question

A metallic rod of length ‘l' is rotated with angular velocity ‘ω' in a uniform magnetic field



b. Find the emf developed between the two ends of the rod. The magnetic field is perpendicular to the motion of the rod.

Answer 1

it should be the answer

Answer 2

Induced emf = d∅/dt

ε= d(BA)/dt

= B dA/dt

Φ=BA cosΦ     here, Φ=0

Φ=BA

A=  area of sector= $1/2 R^{2}$∅

hence, ε= B x d(1/2$R^{2}$∅)/dt

= 1/2 B$R^{2}$ d∅/dt

= Bω$R^{2}$/2