Search any question & find its solution
Question:
Answered & Verified by Expert
An electric current is flowing through a circular coil of radius $\mathrm{R}$. The ratio of the magnetic field at the centre of the coil and that at a distance $2 \sqrt{2} R$ from the centre of the coil and on its axis is :
Options:
Solution:
2972 Upvotes
Verified Answer
The correct answer is:
27
27
Given $:$ Radius $=R$
Distance $\mathrm{x}=2 \sqrt{2} \mathrm{R}$
$$
\begin{aligned}
\frac{B_{\text {centre }}}{B_{\text {axis }}} & =\left(1+\frac{x^2}{R^2}\right)^{3 / 2}=\left(1+\frac{(2 \sqrt{2} R)^2}{R^2}\right)^{3 / 2} \\
& =(9)^{3 / 2}=27
\end{aligned}
$$
Distance $\mathrm{x}=2 \sqrt{2} \mathrm{R}$
$$
\begin{aligned}
\frac{B_{\text {centre }}}{B_{\text {axis }}} & =\left(1+\frac{x^2}{R^2}\right)^{3 / 2}=\left(1+\frac{(2 \sqrt{2} R)^2}{R^2}\right)^{3 / 2} \\
& =(9)^{3 / 2}=27
\end{aligned}
$$
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.