An imaginary sphere drawn round a molecule as centre, with the radius equal to the range of molecular attraction is called ____.

The force of attraction between two molecules of different substance is called ____.

A solid sphere and a hallow sphere of equal radius are raised to same potential. Then

Show that the relative error in computing the volume of a sphere, due to an error in measuring the radius, is approximately equal to three times the relative error in the radius.

Molecular attraction and size of the molecules in a gas are negligible at :

solid sphere of mass 5 kg and radius 1 m is rotating about an axis passing through its centre. find constant tangential force required to rotate the sphere with 10 rad/s in two second . also find number of rotations completed by sphere in that time interval.