Q. In the figure, what is the magnetic field at the point $O$
A) $\frac{\mu_{0}I}{4\pi r}$
B) $\frac{\mu_{0}I}{4\pi r} + \frac{\mu_{0}I}{2\pi r}$
C) $\frac{\mu_{0}I}{4r} + \frac{\mu_{0}I}{4\pi r}$
D) $\frac{\mu_{0}I}{4r} + \frac{\mu_{0}I}{4\pi r}$
Explanation
(c) Magnetic field due to different parts are
$B_{1} = 0$
$B_{2} = \frac{\mu_{0}}{4\pi}.\frac{\pi i}{r}\bigodot$
$B_{3} = \frac{\mu_{0}}{4\pi}.\frac{i}{r}\bigodot$
$\therefore B_{net} = B_{2} + B_{3} = \frac{\mu_{0}i}{4r} + \frac{\mu_{0}i}{4\pi r}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.