Q 12-05-020NEETJEE MainMedium
A solenoid of $1000$ turns per metre carries $2$ A. An iron core of relative permeability $400$ is inserted. The magnetic field inside is ($\mu_0 = 4\pi \times 10^{-7}$ T m/A)
Answer: (C) $0.32\pi$ T
$H = nI = 2000$ A/m. $B = \mu_0\mu_rH = 4\pi \times 10^{-7} \times 400 \times 2000 = 0.32\pi \approx 1.0$ T.
Solution by Sreeraj P, M.Sc Physics