A circular copper disc of 10 cm radius rotates at `20 pi` `radian//sec` about an axis through its centre and perdendicular to the disc. A uniform magnetic field of 0.2 T acts perpendicular to the disc. Calculate the potential difference developed between axis of the disc and the rim. What is the induced current if resistance of disc is 2 ohm ?

Explanation

Here, `r = 10 cm = 10^(-1) m, omega = 20 pi rad//s`
`B = 0.2 T, e = ?`
Potential difference develop between the axis
of the disc and its rim, `e = (1)/(2) B r^(2) omega`
`e = (1)/(2) xx 0.2 (10^(-1))^(2) xx 2 pi = 0.0629 V`
Induced current, `i = (e)/(R ) = (0.0628)/(2) = 0.0314 A`