A closely wound solenoid 80 cm long has 5 layers of windings of 400 turns each. The diameter of the

Question

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.

Professor PC Thomas Classes · Answer

Total turns $N = 5 	imes 400 = 2000$. Number of turns per unit length $n = N/L = 2000/0.8 = 2500$. $B = \mu_0 n I = 4\pi 	imes 10^{-7} 	imes 2500 	imes 8.0 \approx 2.5 	imes 10^{-2}	ext{ T}$.