Q. An expression for the magnetic field strength $B$ at the point between the capacitor plates indicates in figure express $B$ in terms of the rate of change of the electric field strength $ie,\ dE/dt$ between the plates
A) $\frac{\mu_{0}i}{2\pi r}$
B) $\frac{\varepsilon_{0}\mu_{0}r}{2}dE/dt$
C) Zero
D) $\frac{\mu_{0}i}{2r}$
Explanation
(b) $B = \frac{\mu_{0}}{4\pi}\frac{2i_{D}}{r} = \frac{\mu_{0}}{4\pi} \times \varepsilon_{0}\frac{d\phi_{E}}{dt}$
$= \frac{\mu_{0}}{2\pi}\frac{2i_{D}}{r} = \frac{\mu_{0}}{4\pi}\frac{2}{r} \times \varepsilon_{0}\frac{d\phi_{E}}{dt}$
$= \frac{\mu_{0}\varepsilon_{0}\pi r^{2}dE}{2\pi rdt} = \frac{\mu_{0}\varepsilon_{0}r}{2}\frac{dE}{dt}\ $
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.