Question

A metal rod of length 1 m is rotated about one of its ends in a plane at right angle to a uniform magnetic field of induction $2.5\times {10}^{-3}Wb{m}^{-2}$. If it rotates at 1800 rpm, then the induced emf between its ends approximately is :

• A. 0.24 V
• B. 0.12 V
• C. 0.36 V
• D. 0.48 V

Answer 1

The correct option is A 0.24 V

Speed of rotation = 1800 rpm
i.e., $\omega =\frac{1800\times 2\pi }{60}$$=60\pi radian/sec$
$e=\frac{B}{2}{R}^2\omega$$=\frac{2.5\times {10}^{-3}\times 1^2\times 60\pi }{2}$$=0.24V$