Heat Transfer

Question 1

What are the effects of heat?

Answer 1

1. Change in temperature of the body
2. Change in state of the body
3.  Change in size of the body

Question 2

What are the two factors affecting the change in temperature of the body?

Answer 2

1. Quantity if the heat imparted to/rejected fromthe body: When heat is imparted to the body it’s temperature rises while if he does rejected from the body it’s temperature falls
2. Material of the body: Some materials Vista high temperature Waltham to a low temperature even with the same quantity of heat is important to them

Question 3

What is thermal expansion?

Answer 3

Thermal expansion is the change in size of the body due to heating.

Question 4

Explain the effect of temperature on Molecular motion.

Answer 4

When the motion becomes less rapid the temperature decreases or if the temperature decreases the molecular speed decreases. Thus the temperature is directly proportionate to molecular motion.

Question 5

What are the two ways in which a liquid changes into vapor state?

Answer 5

Boiling and Evaporation

Question 6

What is linear expansion?

Answer 6

The increase in length of a solid is called linear expansion.

Question 7

Explain thermal expansion in solids based on its molecular motion.

Answer 7

On heating a solid the average kinetic energy of molecules of the solid increases. They start vibrating about the mean positions with a large amplitude.

Question 8

What are the factors of linear expansion?

Answer 8

Original length of the rod
Increase in temperature
Material of the rod

Question 9

What is superficial expansion of solids?

Answer 9

The increase in area of a plate due to heating is called superficial expansion of solids.

Question 10

What are the factors of superficial expansion of solids?

Answer 10

Initial area of the plate
Increase in temperature
Material of the plate

Question 11

What is the cubical expansion of solids?

Answer 11

The increase in volume of solids on heating is called cubical expansion of solids.

Question 12

What are the factors of cubical expansion?

Answer 12

Initial volume of solid
Rise in temperature
Material of solid

Question 13

What are some applications of Thermal Expansion?

Answer 13

Construction of a bridge
Railway tracks
Riveting
Electric cables and telephone wires

Question 14

How does thermal expansion take place in liquids?

Answer 14

Liquids expand much more than the solids. When heated liquids do not have a definite shape but they have a definite volume therefore the liquids have only cubicle expansion.

Question 15

What is the anomalous behavior of water?

Answer 15

Water contracts on heating from 0 to 4° Celsius and then beyond 4°C on further heating it expands.

Question 16

How does thermal expansion take place in a gas?

Answer 16

Gas also expands when they are heated, gases expand much more than liquids and solids. Like liquids gases do not have a definite shape so they also have all the cubical expansion.