8. A closely wound solenoid 80 cm long has 5 layers of windings of 400 turns each. The diameter of the solenoid is 1.8 cm. If the current carried is 8.0 A, estimate the magnitude of B inside the solenoid near its centre.
The magnitude of the magnetic field at the centre of a solenoid of length l, total turns N and carrying current I is given by
, where is the permeability of free space.
In the given question,
N = number of layers of winding number of turns per winding
N = 5 400 = 2000
I = 8.0 A
l = 80 cm