The solid angle substended at any point inside the surface due to small area ds is given by

Steradian is the solid angle subtended at the centre of the sphere by its surface whose area is equal to ____ of the sphere.

The direction of magnetic field at any point inside the field is given by _________.

Acceleration due to gravity at any point inside the earth

The physical adsorption of gases on the solid surface is due to :

The physical adsorption of gases on the solid surface is due to :