Question

Two identical metallic block resting on a frictionless horizontal surface are connected by a light metallic spring having a spring constant k and an unstretched length L₀. A total charge Q is slowly placed on the system, causing the spring to stretch to an equilibrium length L = 3L₀/2 , as shown. The value of Q, assuming that all the charge resides on the blocks and assuming the blocks as point charges is 

Answer 1

Correct option: (a)

Explanation: 

Since the spring is metallic so the charge distributes equally on both the blocks. Hence a charge Q/2 resides on each block, due to which the blocks will repel each other with a force given by