Page 2 - 4. HOME ASSIGNMENT- FACTORS AFFECTING STATES OF MATTER

a) heat energy required to change 1 Kg solid into liquid completely at
its melting point.
b) heat energy required to convert 1 Kg solid into liquid at room
temperature.
c) Heat energy required to change 1 g of solid into liquid completely.
d) Heat energy required to change 1 Kg of solid into liquid at any
temperature.
Q.8 Latent heat of fusion is amount of
a) heat energy required to change 1 Kg solid into liquid completely at
its melting point.
b) heat energy required to convert 1 Kg solid into liquid at room
temperature.
c) Heat energy required to change 1 g of solid into liquid completely.
d) Heat energy required to change 1 Kg of solid into liquid at any
temperature.
Q.9 When we put a drop of spirit on our palm, we feel cold because
a) It absorbs the latent heat from our palm for evaporation
b) It provides a cooling sensation
c) It is stored at a low temperature
d) Its temperature is very low.
Q.10 During change of state the temperature remains constant because:
a) Matter can not absorb heat during change of state.
b) Heat energy supplied during change of state is used up in
overcoming the inter molecular forces.
c) Both (a) and (b) are correct
d) Both (a) and (b) are false.

SUBJECTIVE
Q.1 We feel cold when we touch a piece of ice. Why?
Q.2 Doctors spray little ether before performing a minor surgery. Give reasons.
Q.3 Why does the temperature of a substance remain constant during its
melting point or boiling point?
Q.4 Putting wet clothes on the forehead of persons suffering from fever
reduces the temperature, Justify.
Q.5 Define the following with examples from daily life
a) Latent heat of fusion
b) Latent heat of vapourisation.

NCERT Textbook-Std-IX-Science
Page No 12 Q.7 and Q.8

2