Consider a tightly wound 100 turn coil of radius 10 cm, carrying a current of 1 A. What is the magnitude of the magnetic field at the centre of the coil?

Explanation

Since the coil is tightly wound, we may take cach circular lement to have the same radius R - 10 cm=0.1 m. The number of tums N=100. The magnitude of the magnetic field is
`B = (mu_0 N)/(2R) = (4pi xx 10^(-7) xx 10^(2) xx 1)/(2 xx 10^(-1)) = 2pi xx 10^(-4) = 6.28 xx 10^(-4) T`