Q. For the magnetic field to be maximum due to a small element of current carrying conductor at a point, the angle between the element and the line joining the element to the given point must be
A) $0{^\circ}$
B) $90{^\circ}$
C) $180{^\circ}$
D) $45{^\circ}$
Explanation
(b) From Biot-Savar’s law, the magnetic field $d\mathbf{B}$ at $P$ due to the current element $i\ dl\ $is given by
$dB = \frac{\mu_{0}}{4\pi}\frac{i\ dl\sin\theta}{r^{2}}$
Where $\theta$ is angle between $id\ $I and r. Maximum value of $\sin{\theta = 1,}$ when $\theta = 90{^\circ}.$ Hence, for magnetic field to be maximum the angle is $90{^\circ}.$
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Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.