Question

Q.1. Define the following terms:
a. Heat energy/internal heat energy

b. Latent heat

c. Thermal expansion

d. Linear expansion of solids

e. Cubical expansion of liquids

f. Anomalous expansion of water


Q.2. Name/State the following:

a. The size of a molecule

b. One example of melting

c. One example of condensation

d. Glass which expands negligibly on heating,

e. An alloy of iron and nickel which expands negligibly on heating

f. One application of the thermal expansion of liquids


Q.3. Give scientific reasons for the following:
a. The rate of evaporation of the liquid increases when air is blown over the liquid

b. Cooling is produced when a liquid evaporates

c. Telephone wires break in winter

d. One end of a steel girder in a bridge is kept on rollers instead of fixing it in a pillar

e. Iron rims are heated before they are fixed on the wooden wheels

f. A glass stopper stuck in the neck of a bottle can be removed by pouring hot water on

the neck of the bottle

g. Liquids have only cubical expansion


Q.4. Answer the following questions:

a. Evaporation is a surface phenomenon. Explain the given statement on the basis

of molecular motion

b. Explain boiling on the basis of molecular motion

c. State two points of difference between evaporation and boiling

d. Two iron rods-one 10m long and the other 5m long are heated to the same rise in

temperature. Which rod will expand more and why?

e. One rod of copper and another identical rod of iron are heated to the same rise in

temperature. Which rod will expand more and why?

f. Explain thermal expansion in gases on the basis of molecular motion

g. How does the density of a substance ( solid, liquid , gas) change on heating?​

Answer 1

Answer:

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