Question

A circular loop of radius 4.0cm is placed in a horizontal plane and carries an electric current of 5.0A in the clockwise direction as seen from above. Find the magnetic field (a) at a point 3.0cm above the centre of the loop (b) at a point 3.0cm below the centre of the loop.

Answer 1

At O P the vector B must be directed downwards

We Know 

B at the axial line at O & P

a = 4cm = 0.04m

d = 3cm = 0.03m

= 40 × 10^–6 = 4 × 10^–5T downwards in both the cases