1) A point charge q is placed inside a metallic hollow sphere. The sphere itself carries a load 3q. What is the charge on the inner surface of the sphere? What is the load on the outer surface of the sphere ?

2) A particle of mass 75.0 g charged with 35.00 C is held fixed at the origin and a particle of 20.0 g mass charged with 63.00 C at a distance of 7.20 cm from the first, and let it go. What is the speed of the second particle when it is at a distance of 19.60 cm ?

3) What work must be done to bring from infinity three charges +q, q and q and place them at the corners of a equilateral triangle of side L ?