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 each circular element to have the same radius R = 10 cm = 0.1 m. The number of turns N = 100. The magnitude of the magnetic field is
`B= (mu_0 NI)/(2R) = (4pi xx 10^(-7) xx 10^2 xx 1)/(2 xx 10^(-1) ) = 2pi xx 10^(-4) = 6.28 xx 10^(-4)T`