Question

A wire carrying a current of $4A$ is in the form of a circle. It is necessary to have a magnetic field of induction $\pi \times 10^{-5}T$ at the centre. The radius of the circle must be

• A. 0.08 cm
• B. 0.8 cm
• C. 8 cm
• D. 80 cm

Answer 1

Answer: (C)

$r=\frac{{\mu }_{0}ni}{2B}$