FBISE 9th class Physics Chapter 9 Transfer Of Heat Short Questions with answers are combined for all 9th class(Matric/ssc) Level students. Here You can prepare all Physics Chapter 9 Transfer Of Heat short question in unique way and also attempt quiz related to this chapter. Just Click on Short Question and below Answer automatically shown. After each question you can give like/dislike to tell other students how its useful for each.
Class/Subject: 9th Class Physics
Chapter Name: Transfer Of Heat
Board: Federal Board
- Federal Boards 9th Class Physics Annual Examination
- Schools 9th Class Physics December Test
- Federal 9th Class Physics Test
- Entry Test questions related Physics
FBISE 9th Class Physics Chapter 9 Transfer Of Heat Short Questions Answers
The mode of transfer of heat by vibrating atoms and free electrons in solids from hot to cold parts of a body is called conduction of field.
All metals are good conductors of heat. The substances through which heat conduct easily are called conductors. E.g. copper, iron, aluminum, etc.
Transfer of heat by actual movement of molecules from a hot place to a cold place is known as convection.
i. Convection currents set up by electric, gas, or coal heaters help to warm our houses and offices.
ii. Central heating systems in buildings work on the same principle of convection.
A glider looks like a small airplane without an engine. Glider pilots use upwards movement of hot air current due to convection of heat. These rising currents of hot air are called thermals. Glider ride over these thermals. The upward movement of air currents in thermals helps them to stay in the air for a long period.
Radiation is the mode of transfer of heat from one place to another in the form of waves called Electromagnetic waves.
Metals are good conductors of heat because of the valence electrons’ freedom of motion within a metal. The free-moving electrons transmit heat quickly.
Because the space between particles is faster apart in either the gas or liquid state. Solid substances particles are very close together, whereas gas particles will move are far apart as possible. When the particles are faster apart it makes the transfer of energy much less efficient. That is why the conduction of heat does not take place in gases.
The flower that transfers heat with enough load is called a convection current. When you heat water, the cold molecules are heavy or dense, so they sink to the bottom. But the hot ones are less dense, so they go up as they go up, they get cold and also get heavy. So, they sink and the cycle goes on and, on this process, will continue due to convection current.
Sunlight or solid radiation is essentially photons or packets of energy emitted from the sun’s surface which can travel through the vacuum of space at the speed of light by the process of radiation. This comes to us in a range of wavelengths, including visible light, Ultraviolet, and Infra-red radiation.
Warming that result when solar radiations are trapped by the atmosphere, caused by atmospheric gases that allow sunshine to pass through but absorb heat that is radiated back from the warmed surface of the earth.
Carbon dioxide and water also behave similarly to radiations as glass or polythene Earth’s atmosphere contains carbon dioxide and water vapor. It causes the greenhouse effect and thus maintains the temperature of the Earth.
The rate at which various surfaces emit heat depends upon the nature of the surface. These surfaces can be compared using Leslie’s cube.
A Leslie cube is a metal box having to face of different nature. The four faces of Leslie’s cube may be as follows:
i. A shiny silvered surface
ii. A dull black surface
iii. A white surface
iv. A colored surface
The amount of heat that flows in unit time is called the rate of flow of heat.
Land and sea breezes are the result of convection. On a hot day, the temperature of the land increases more quickly than the sea. It is because the specific heat of land is much smaller as compared to water. The air above land gets hot and rises. Cold air from the sea begins to move towards the land, it is called sea breeze.
At night, the land cools faster than the sea. Therefore, the air above the sea is warmer, rises and the cold air from the land begins to move towards the sea. It is called land breeze.
Those birds which use the thermal for air their flight is called thermal climbers e.g. Eagles, hawks, and vultures.
While the surface is a good reflector but a bad absorber. That is why we use white clothes in summer