Question

Two charges q1 and q2 are placed such that, the electric field at one-fourth of the way from
q1 to q2 is zero. Determine the ratio q1:q2
(1) 1:9 (2) 2:1 (3) 1:16 (4) 16:1

Answer 1

At this point we have

$$E_1=E_2$$

$$\frac{kq_1}{(\frac{d}{4})^2}=\frac{kq_2}{(\frac{3d}{4})^2}$$

$$9q_1=q_2$$

Answer: (1) 1:9