PHYSICS [2 Mark Question Answer]

The three factors that decide the state of the matter are the strength of intermolecular force of attraction, intermolecular space and the kinetic energy of the molecules.

Intermolecular force : Intermolecular force can be defined as the force of attraction which the molecules of matter always exert on each other.
Intermolecular spaces : It is the distance between the molecules of matter.

The force of adhesion between the molecules of water and glass is responsible for the downward curve of water placed in the glass tube. Due to this force, the water molecules cling to the walls of the glass tube and travel up along these walls as far as the forces of gravity and cohesion between the molecules of water allow them.

When temperature of a substance increases, the molecules gain heat energy. They start moving faster. As the kinetic energy of the molecules is directly proportional to their velocities, therefore, their kinetic energy increases with increase in temperature.

When a solid melts, the kinetic energy of its molecules increases. So, the molecules start moving faster, change their positions easily and slide over one another. As a result, the intermolecular space between the molecules increases and the solid gets converted to its liquid form.