Q 12-05-045JEE MainJEE Main 2023 (10 Apr, Shift 1)Easy
The current required to be passed through a solenoid of $15$ cm length and $60$ turns in order to demagnetise a bar magnet of magnetic intensity $2.4\times10^3\ \text{A m}^{-1}$ is ______ A.
Numerical value type. Enter your answer.
Answer: 6
The solenoid must supply $H=nI$ equal to the coercive intensity: $I=\dfrac{2400\times0.15}{60}=6$ A.
Solution by Sreeraj P, M.Sc Physics