Question:
A solenoid of 1000 turns per metre has a core with relative permeability 500 . Insulated windings of the solenoid carry an electric current of $5 \mathrm{~A}$. The magnetic flux density produced by the solenoid is :
(permeability of free space $=4 \pi \times 10^{-7} \mathrm{H} / \mathrm{m}$ )
Correct Option: 1
Solution:
$\mathrm{B}=\mu \mathrm{nI}=\mu_{0} \mu_{\mathrm{r}} \mathrm{nI}$
$\mathrm{B}=4 \pi \times 10^{-7} \times 500 \times 1000 \times 5$
$\mathrm{~B}=\pi$ Tesla