Question

5. A negative charge of magnitude q is placed at the origin. Two positive charges of magnitude
q are placed along the horizontal axis at L and −L.
(i) What is the net electrical force on the negative charge?

Answer 1

The Coulomb law states

$$F=k\frac{q_1q_2}{r^2}$$

Therefore

$${\vec F_1}=-\vec F_2$$

So, the net electrical force on the negative charge is zero.