Question

A vertical copper disc of diameter `20cm` makes `10` revolution per second about a horizontal axis passing through its centre. A uniforjm magnetic field `10^(-2)T` acts perpendicular to the plane of the disc. Calculate the potential defference between its centre and rim in volts.

Answer 1

Dics is equivalent to a length `r` . Divide dics into rods, each rod i sreplaced by a battery and these batteries are in parallel.
`r=(20)/(2)=10cm=0.1m`
`omega=10xx2pi=20pirad/sec`
`B=10^(-2)T`
`e=(1)/(2)Bomegar^(2)`
`=(1)/(2)(10^(-2))(20pi)(0.1)^(2)`
`V_(0)-V_(A)=3.14xx10^(-3)V`