A long solenoid of turn density carries a steady current

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

Problem

A long solenoid of turn density

n

carries a steady current

I

. If an iron core of relative permeability

\mu_r

is inserted completely so that it fills the interior, the magnetic field inside the solenoid becomes (a)

\dfrac{1}{\mu_r}

times its initial value (b)

\mu_r

times its initial value (c)

\sqrt{\mu_r}

times its initial value (d) unchanged