Question

a) Find the distance from a point charge q=100nC where the field intensity is equal to E=6kN/C

b) The charge density on each of two parallel plates is of 5μc/m². Find the intensity of the electric field E between both plates.

Answer 1

a) Write the expression for field and determine the distance:

$$E=\frac{kq}{r^2},\\\space\\ r=\sqrt{kq/E}=0.39\text{ m}.$$

b) The field is

$$E=\frac\sigma{2\epsilon_0}=282\text{ kN/C}.$$