On connecting a battery to the two corners of a diagonal of a square conductor frame of side `a` the magnitude of the magnetic field at the centre will be

Options

A. `(mu_(0))/(pia)`
B. `(mu_(0))/(sqrt2pia)`
C. Zero
D. `(sqrt2mu_(0))/(pia)`

Answer

C

Explanation

The current will be divided as `I /2 and I/2` at A and we get two sets of parallel wires carrying currents in the same direction. But the magnetic fields produced by them at the centre O will be equal and opposite. Hence the resultant magntic field at teh centre will be zero.