Question

The magnetic field at the centre of semi-circular wire carrying current $i$ is

• A. $\frac{{\mu }_{0}i}{2r}$
• B. $\frac{{\mu }_{0}i}{4r}$
• C. $\frac{{\mu }_{0}i}{r}$
• D. $\frac{{\mu }_{0}i}{2\pi r}$

Answer 1

Answer: (B)

Magnetic field at centre of a circular coil,
$B=\frac{{\mu }_{0}Ni}{2r}$
Here $N=\frac{1}{2}$
$\therefore B=\frac{{\mu }_0\left(\frac{1}{2}\right)i}{2r}$
$=\frac{{\mu }_{0}i}{4r}$