Question

A charge "Q" and "2Q" are 0.05 meters apart and isolated. The ratio of the electrostatic force on the charge Q to the force on charge 2Q is:

• A. 2 : 1
• B. 1 : 1
• C. 1 : 2
• D. 1 : 4

Answer 1

Answer: (B)

1 : 1

According to Newton's 3rd law, every action has equal and opposite reaction.

Thus the force exerted by charge on $Q$ due to $2Q$ is equal but opposite in direction to the force exerted by charge on $2Q$ due to $Q$ i.e $F_Q=F_{2Q}$

$⟹$ $\frac{F_Q}{F_{2Q}}=1$