Question

Four point charges (two with q= 2.50 x 10^–6 C and two with q= –2.50 x 10^–6 C) are situated at the corners of a square of side 1.00 m as shown. Find the resultant force that the charge at A will experience due to the charges as the other corners of the squares.

Answer 1

$$F=\dfrac{q^2}{4\pi\epsilon_0r^2}\bigg(2\cos45°-\dfrac12\bigg)=0.05\text{ N}.$$