A circular coil of 50 turns and radius 5 cm produces a magnetic field of 2 10⁻⁴ T at its centre. The current flowing through the coil is (Take permeability of free space as 4 10⁻⁷ SI units ):

Step-by-step solution

The magnetic field at the centre of a circular coil of N turns is given by: B = ₀ N I 2 R Rearranging for current I : I = 2 R B ₀ N Given: N = 50 R = 5 cm = 0.05 m B = 2 10⁻⁴ T ₀ = 4 10⁻⁷ T m A ⁻¹ Substituting the values: I = 2 0.05 2 10⁻⁴ 4 10⁻⁷ 50 I = 0.2 10⁻⁴ 200 10⁻⁷ I = 2 10⁻⁵ 2 10⁻⁵ = 1 A Answer: 1 A