Figure. Shows a small loop carrying a current I. The curved portion is an arc of a circle of radius R and the straight portion is a chord to the same circle subtending an angle `theta`. The magnetic induction at centor O is

Options

A. zero
B. always inward irrespective of the value `theta`
C. inward as long as `theta` is less than `pi`
D. always outward irrespective of the value of `theta`

Answer

C

Explanation

(c) Due to current shown in figure, the magnetic field with loop
is outwards. So field at O should be inward because magnetic
field lines from closed loop. But if `theta gt pi`, then point O will lie within loop and for a point within loop magnetic field is
outward.