Gravitation

Assertion : Gravitational potential and gravitational potentail energy, both are related to the work done by gravitational force in the gravitational field Reason : Gravitational field strength is related to the gravitaional force in gravitational field.

Choose the correct alternative : (a) If the gravitational potential energy of two mass points infinite distance away is taken to be zero, the gravitational potential energy of a galaxy is (positive /negative/zero). (b) The universe on the large is shaped by (gravitational/electromagentic) forces, on the atomic scale by (gravitational/electromagnetic) forces, on the nuclear scale by (gravitational/electromagnetic/strongnuclear) forces.