Q.
A circular coil of wire consisting of 100 turns each of radius 9cm carries a current of 0.4A. The magnitude of the magnetic field at the centre of coil is [μ0=12.56×1−7 SI Unit]
Given, number of turns, n=100,
radius of coil, r=9cm=9×10−2m
and current flow in the coil, I=0.4A
The magnitude of the magnetic field at the centre of a coil of n turns is given by B=2rμ0nI...(i)
Substituting given values in Eq. (i), we get ⇒B=2×10−1×9×10−21256×10−7×100×0.4 =2.79×10−4T