Q. Rate of change of torque $\tau$ with defelection $\theta$ is maximum for a magnet suspended freely in a uniform magnetic field of induction B, when
A) $\theta = 0{^\circ}$
B) $\theta = 45{^\circ}$
C) $\theta = 60{^\circ}$
D) $\theta = 90{^\circ}$
Explanation
(a) As $\tau = MB\ \sin\theta$
$\ \ \ \frac{d\tau}{d\theta} = MB\ \cos\theta$
It will be maximum, when $\theta = 0{^\circ}.$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.