Question

A circular loop of radius 5 cm carries an electric current. Let P and Q be two points, on the axis of the loop at distance 1 m and 2 m respectively from the center. If the magnetic field at P due to the current is 16mT, that at Q will be about

• A. 8 m T
• B. 4 m T
• C. 2 m T
• D. 1 m T

Answer 1

Answer: (C)

$B=\frac{{\mu }_{0}ni{r}^2}{2(r^2+x^2{)}^{3/2}}$