Question

A point charge is moving in a circle with constant speed. Consider the magnetic field produced by the charge at a fixed point $P$ (not at the center of circle) on the axis of the circle.

• A. it is constant in magnitude only
• B. it is constant in direction only
• C. it is constant both in direction and magnitude both.
• D. it is constant neither in magnitude nor in direction both.

Answer 1

Answer: (A)

it is constant in magnitude only

The point charge moves in circle as shown in figure. The magnetic field vectors at a point $P,\overrightarrow{B_A}$ and $\overrightarrow{B_C}$ at the instant the point charge is at $A$ and $C$ respectively, as shown in figure.