question_answer

A large solid insulating sphere with uniformly distributed positive charge has a smooth narrow tunnel through its centre. A small particle with negative charge, initially at rest far from the sphere, approached it along the line of the tunnel, reaches its surface its surface with a speed v, and passes through the tunnel. Its speed at the centre of the sphere will be- (neglect all resistance forces & friction acting on particle except electrostatic force)

Answer:

1.22