Question

Two infinitely parallel plates have charges 1.6 microcoulomb per meter square and 2 microcoulomb per meter square if they are arranged close to each other what is the electric field
( A ) in the region outside the plates
(B) in between the page

Answer 1

The fields from the first and the second plate:

$$E_1=\frac{\sigma_1}{2\epsilon_0},\space E_2=\frac{\sigma_2}{2\epsilon_0}.$$

Therefore, the field outside the plates will be

$$E_o=E_2-E_1=\frac{\sigma_2-\sigma_2}{2\epsilon_0}=22.6\text{ kV/m},$$

the field between the plates is

$$E_i=E_2+E_1=\frac{\sigma_2+\sigma_2}{2\epsilon_0}=203\text{ kV/m}.$$