Question

A 1200-nF capacitor with circular parallel plates 2.0 cm in diameter is accumulating charge at the rate of 35 mC/s at some instant in time. (A) What will be the magnitude of the induced magnetic field 10.0 cm radially outward from the center of the plates?

Answer 1

Answer:

$B = 7 \times 10^{-8} T$

Explanation:

As we know that charge on the plates of capacitor is changing at rate given as

$i = \frac{dq}{dt} = 35 mC/s$

now this rate of charging the plates will give the displacement current in the region between the plates

Now by Ampere's law we can say

$\int B . dl = \mu_0 i$

now we have

$B(2\pi r) = \mu_0 i$

$B = \frac{\mu_0 i}{2\pi r}$

$B = \frac{2 \times 10^{-7} (35 \times 10^{-3})}{0.10}$

$B = 7 \times 10^{-8} T$