Question

A large parallel plate capacitor with uniform surface charge σ on the upper plate & -σ on the lower is moving with a constant speed V as shown in figure, (non-conducting plates)

• A. zero
• B. $\frac{\mu_0 \sigma v}{4}$
• C. $\frac{\mu_0 \sigma v}{2}$
• D. $\mu_0 \sigma v$

Answer 1

Answer: (C)

$\frac{\mu_0 \sigma v}{2}$

Answer 2

The magnetic field produced by an infinite current sheet with surface current density K is $\frac{\mu_0 K}{2}$. The surface current density on each plate is $K = \sigma V$. Assuming the question asks for the magnitude of the field due to one plate, it is $\frac{\mu_0 \sigma V}{2}$.