Q. A charge is fired through a magnetic field. The force acting on the charge is maximum when the angle between the direction of motion of charge and the magnetic field is
A) Zero
B) $\frac{\pi}{4}$
C) $\pi$
D) $\frac{\pi}{2}$
Explanation
(d) Magnetic field exerts force (F) on moving charge $(q)$ is given by
$\mathbf{F} = q\mathbf{v} \times \mathbf{B} = q\mathbf{vB}\sin\theta$
Where v is velocity, B the magnetic field, and $\theta$ the angle between the two. $F$ is maximum when $\sin\theta$ is maximum.
Therefore, $\theta = \frac{\pi}{2},\sin{\frac{\pi}{2} = 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.