State the correct expression for the magnetic field at the centre of a long

PHYSICS · Single correct · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism

Problem

State the correct expression for the magnetic field

B

at the centre of a long, tightly wound solenoid carrying current

I

with

n

turns per unit length. (a)

B = \dfrac{\mu_0 n I}{2}

(b)

B = \dfrac{\mu_0 I}{2\pi r}

(c)

B = \mu_0 n I

(d)

B = \mu_0 N I