Acircular copper disk of diameter d=10 cm rotates at frequency =1800 rev/min about an axis through its center and at right angles to the disk. a uniform magnetic field b of 10,000 gauss is perpendicular to the disk. what potential difference e develops between the axis of the disk and its rim?

e=2356.125 V

Explanation:

Given that

D= 10 cm  = 0.1 m

R= 0.05

B= 10,000

Angular speed ,ω = 1800 rev/min

Speed in rad/s given as

ω= 188.49 rad/s

The potential difference given as

e= B R v

v=average speed

By putting the values

e=2356.125 V

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.