Question

A copper disc of radius 10 cm rotates 20 times per second with its plane perpendicular to a uniform magnetic field . If the induced EMF between the center e and edge of the disc is 3.14 mV Calculate the intensity of the field​

Answer 1

Answer:

Consider a small radial segment of dx at a distance x from the centre of the disc. Velocity of this segment is ωx. Emf induced across this segment

de=vBL=ωxBdx

Total emf induced across radius of disc r

E=

2

1

Bωr

2

As ω=2πn where n is number of revolutions per second

B=0.1T,r=0.1m,ω=10rev/s=20πrad/s

E=

2

1

×0.1×0.01×20π=π×10

−2

V

Answer 2

Refer to the attachment for your answer!