Question

For a given distance from a current element, the magnetic induction is maximum at an angle measured with respect to axis of the current. The angle is :

• A. $\frac{3\pi }{4}$
• B. $\frac{\pi }{4}$
• C. $\frac{\pi }{2}$
• D. $2\pi$

Answer 1

Answer: (C)

$\frac{\pi }{2}$

Magnetic field due to small current element is given as

$B=\frac{{\mu }_o}{4\pi }\frac{\overrightarrow{idl}\times \hat{r}}{r^2}$

$B=\frac{{\mu }_o}{4\pi }\frac{idlr\sin \theta }{r^3}$

$\sin \theta =1$ for $\theta =\frac{\pi }{2}$