Question

Two large metal plates of area 0.7 m2 face each other. They are 5.1 cm apart and have equal but opposite charges on their inner surfaces. If the magnitude E of the electric field between the plates is 55 N/C, what is the magnitude of the charge on each plate? Neglect edge effects.

Answer 1

Explanation:

The given data is as follows.

    Area (A) = 0.7 $m^{2}$.

  Electric field between the plates, (E) = 55 N/C

Since, electric field is related to surface charge density as follows.

          $\sigma = \frac{Q}{A}$

Also,    E = $\frac{\sigma}{\epsilon_{o}}$

or,        $\sigma = \epsilon_{o} E$

Therefore, charge will be calculated as follows.

          Q = $\sigma \times A = \epsilon_{o} E \times A$

             = $8.854 \times 10^{-12} \times 55 \times 0.7$

             = $3.41 \times 10^{-10} C$

             = 341 pC

Thus, we can conclude that magnitude of the charge on each plate is 341 pC.