A simple pendulum with charge bob is oscillating as shown in the figure. Time period of oscillation is `T` and angular ampliltude is `theta`. If a uniform magnetic field perpendicular to the plane of oscillation is switched on, then

Options

A. T will decrease but `theta` will remain constant
B. T wil remainconstant but `theta` will decrease
C. Both T and `theta` will remain the same
D. Both T and `theta will decrease

Answer

C

Explanation

Mangetic force is always perpendicular to velocity. So it will always act in radial direction which will change tension at differenct points. But, time period and `theta` will remain unchanged.