Question

A tightly wound 100 turns coil of radius 10 cm carries a current of 7 A. The magnitude of the magnetic field at the centre of the coil is ______.

(Take permeability of free space as 4π × 10⁻⁷ SI unit).

Options

• 4.4 mT

• 44 T

• 44 mT

• 4.4 T

Answer 1

A tightly wound 100 turns coil of radius 10 cm carries a current of 7 A. The magnitude of the magnetic field at the centre of the coil is 4.4 mT.

Explanation:

Given: Number of turns (N) = 100

Radius (r) = 10 cm

Current (I) = 7 A

Magnetic field (B) = `(mu_0 N I)/(2 R)`

= `(4 pi xx 10^-7 xx 100 xx 7)/(2 xx 10 xx 10^-2)`

= `(28 pi xx 10^-4)/2`

= 14 π × 10⁻⁴  T

≈ 44 × 10⁻⁴  T

≈ 44 m T