If $$g$$ is the acceleration due to gravity on the earth's surface, the gain in the potential energy of an object of mass $$m$$ raised from the surface of the earth to a height equal to the radius $$R$$ of the earth is

The time period of an earth satellite in circular orbit is independent of

A wire fixed at the upper end stretches by length $$l$$ by applying a force $$F.$$ The work done in stretching is

If two soap bubbles of different radii are connected by a tube