Chapter 22, Problem 2P

To determine

The magnitude of the field after the capacitor is fully charged.

Answer to Problem 2P

The answer is $7.00\times {10}^{-8}T$

Explanation of Solution

Given info:

Current, $I=35.0mC/s=35.0\times {10}^{-3}A$

Permittivity of free space, ${\epsilon }_0=8.85\times {10}^{-12}F/M$

Radius, $R=10cm=0.100m$

Formula used:

It is known that:

  $B=\left(\frac{{\mu }_0}{4\pi }\right)\frac{2I}{R}$

Where,

  $B$ is magnetic field

  $I$ is current

  $R$ is radius

  ${\mu }_0$  is the permeability of free space

  $\pi$ is constant

Calculation:

Substitute given and known values in formula, $B=\left(\frac{{\mu }_0}{4\pi }\right)\frac{2I}{R}$

  $B=\frac{\left({10}^{-7}T\cdot m/A\right)2\left(35.0\times {10}^{-3}A\right)}{\left(0.100m\right)}$

  $B=7.00\times {10}^{-8}T$

Conclusion: The required field is $7.00\times {10}^{-8}T$ .