Question

Two small objects each with a net charge of Q (positive) exert a force of magnitude F on each other. We replace one of the objects with another whose net charge is 4Q. The original magnitude of the force on the Q charge was F; what is the magnitude of the force on the Q now?
A. 16F
B. 4F
C. F
D. F/4

Answer 1

Answer:

option B

Explanation:

we know,

Force between two charge is calculated by

$F = \dfrac{kq_1q_2}{r^2}$

r is the distance between the two charges

k is Coulomb constant.

give two small object with charge Q

now, Force

$F = \dfrac{kQQ}{r^2}$......(1)

now,

New force if another charge is equal to 4 Q

$F' = \dfrac{kQ(4Q)}{r^2}$

$F' = 4\dfrac{kQQ}{r^2}$

now from equation 1

$F' = 4 F$

Hence, the correct answer is option B