A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. What is the magnitude of the magnetic field B at the centre of the coil?

Explanation

We are given
`n = 100 a = 8. 0 cm = 8 xx 10 ^(-2) m , I = 0. 40 A`
Also `mu _(0) = 4 pi xx 10 ^(-7) T m A ^(-1)`
We are to calculate, magnetic field, B,
Using relation, `B = ( mu _(0) n I )/( 2a) = ( 4 xx 2. 1 4 xx 10 ^(-7) xx 100 xx 0. 40)/( 2 xx 8 xx 10 ^(-2)) = 3. 14 xx 10 ^(-4) T`
`therefore B = 3. 14 xx 10 ^(-4) T`