$(a)$ Give an example where a change in physical state occurs due to a change in pressure.
$(b)$ State two factors that determine the rate of diffusion of a liquid in another liquid.

Fill in the blanks :
$(a)$ Evaporation of a liquid at room temperature leads to a ........... effect.
$(b)$ At room temperature,the forces of attraction between the particles of solid substances are ........... than those which exist in the gaseous state.
$(c)$ The arrangement of particles is less ordered in the ........... state. However,there is no order in the ........... state.
$(d)$ ........... is the change of solid state directly to vapour state without going through the ........... state.
$(e)$ The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called ...........

$(a)$ Define matter and write its three states.
$(b)$ Explain how these states of matter arise due to variation in the characteristics of the particles.

The non-$SI$ and $SI$ units of some physical quantities are given in Column $A$ and Column $B$ respectively. Match the units belonging to the same physical quantity:

Column $A$	Column $B$
$(a)$ degree Celsius	$(i)$ kilogram
$(b)$ centimeter	$(ii)$ pascal
$(c)$ gram per centimetre cube	$(iii)$ metre
$(d)$ bar	$(iv)$ kelvin
$(e)$ milligram	$(v)$ kilogram per metre cube

Comment on the following statements :
$(a)$ Evaporation produces cooling.
$(b)$ Rate of evaporation of an aqueous solution decreases with increase in humidity.
$(c)$ Sponge though compressible is a solid.

Give reasons for the following observations:
$(a)$ Naphthalene balls disappear with time without leaving any solid.
$(b)$ We can get the smell of perfume sitting several metres away.