Question

A circular coil has 150 turns and a mean diameter of 20 cm. It carries a current of 10 A. What is the strength of the magnetic field at a point on its axis at a distance of 5 m from the centre of the coil?

Options

• 4π x 10^-7 T

• 2.4π x 10^-7 T

• 4π x 10^-8 T

• 2.4π x 10^-8 T

Answer 1

2.4π x 10^-8 T

Explanation:

Since z >> R, B = `(mu_0  "In"  "R"^2)/(2"Z"^3)`

= `(4pi xx 10^-7 xx 10 xx 150 xx (0.1)^2)/(2 xx (5)^3)`

= `2.4pi xx 10^-8`T