# A current I flows in an infinity long wire with cross section

Question:

A current I flows in an infinity long wire with cross section in the from of a semicircular ring of radius $R$. the magnitude of the magnetic induction along its axis is :-

1. $\frac{\mu_{0} I}{2 \pi R}$

2. $\frac{\mu_{0} I}{4 \pi R}$

3. $\frac{\mu_{0} I}{\pi^{2} R}$

4. $\frac{\mu_{0} I}{2 \pi^{2} R}$

Correct Option: , 3

Solution: