Question

Maximum magnetic field is found at a distance $x$ from the centre along the axis of circular loop $($radius $=R)$ of the current carrying conductor. What is the value of $x?$

• A. $\frac{R}{2}$
• B. Zero
• C. $R$
• D. $\frac{R}{\sqrt{2}}$

Answer 1

The correct option is B Zero


The magnetic field at distance $x$ from the centre along the axis of circular loop $($radius$=R)$ of the current carrying conductor is given by,

$$B=\frac{{\mu }_0}{4\pi }\frac{2\pi I{R}^2}{(R^2+x^2{)}^{3/2}}$$
So, from the above expression it is evident that as $x$ increases $B$ decreases.

Also, at $x=0,$ $B=$ maximum.

Hence, option $\left(B\right)$ is the correct answer.