Question

Determine the electric field intensity at a point P midway between two point charges of +2.0x10^-7 C and -2.0x10^-7 C if they are 100 cm apart.

Answer 1

Answer

Both the charges are same in magnitude and apposite in nature. So electric field at midway between charges will be in same direction and equal in magnitude. So

$E_{net}=\frac{Kq}{r^2}+\frac{Kq}{r^2}$

$E_{net}=\frac{2Kq}{r^2}$

$E_{net}=\frac{2(9\times10^9)(2\times10^{-7})}{(0.5)^2}=144\times10^{2}N$