Two charges A and B are fixed in place, at different distances from a certain spot. At this spot the?

Question

Two charges A and B are fixed in place, at different distances from a certain spot. At this spot the potentials due to the two charges are equal. Charge A is .18m from the spot, while charge B is .43 m from it. Find the ratio qB/qA.

I plugged in the distances into the ratio: .43/.18 = 2.389

but this solution seems way too easy so i'm afraid I answered this question wrong...can someone please help me?

Answer 1

Think of it this way:

V1 = V2

kqA / rA = kqB / rB

Use that to solve for the charge ratio of B over A.

qB / qA = rB / rA

= 0.43 m / 0.18 m

= 2.4

You are correct.