Question

The magnetic field at the centre of current carrying coil is

• A. $\frac{{\mu }_{0}ni}{2r}$
• B. $\frac{{\mu }_0}{2\pi }\frac{ni}{r}$
• C. $\frac{{\mu }_{0}ni}{4r}$
• D. ${\mu }_{0}ni$

Answer 1

The correct option is A $\frac{{\mu }_{0}ni}{2r}$

Magnetic field at the centre of current carrying coil is
$B=\frac{{\mu }_0}{4\pi }.\frac{2\pi ni}{r}=\frac{{\mu }_{0}ni}{2r}$