Q 12-04-134JEE MainJEE Main 2023 (8 Apr, Shift 2)Easy
The ratio of magnetic field at the centre of a current carrying coil of radius $r$ to the magnetic field at distance $r$ from the centre of coil on its axis is $\sqrt x:1$. The value of $x$ is ______.
Numerical value type. Enter your answer.
Answer: 8
$\dfrac{B_c}{B_{axis}}=\dfrac{(r^2+r^2)^{3/2}}{r^3}=2\sqrt2=\sqrt8$, so $x=8$.
Solution by Sreeraj P, M.Sc Physics