Conduction,Convection and Radiation

Convection can take place in solids.

• True

• False

Which process is going on in the picture?

• Convection currents in water.

• Water is getting dark as there some impurities down there 

• My mother is boiling water for her tea

What is convection?

• It's a mode of transfer of heat in fluids wherein the molecules actually move from one part of the fluid to another of the fluid to others.

• It's a mode of transfer of heat in solids wherein the molecules actually don't move from one part of the solid to others.

Substances which allow heat to flow through them easily are

How does Radiation or radiant energy travel?

• It travels in straight line in the form of waves.

• It travels in curved lines in form of waves.

• It travels in an auto.

Arrange the following with reference to their meanings.

Column A

1)- Radiation-

2)- Conduction-

3)- Convection-

Column B

a)- Directly without using any medium.

b)- By actual movement of molecules in fluids.

c)- From one molecule to another in a solid.

• 1)- Radiation- By actual movement of molecules in fluids.

  2)- Conduction- Directly without using any medium.

  3)- Convection- From one molecule to another in a solid.

• 1)- Radiation- Directly without using any medium.

  2)- Conduction- By actual movement of molecules in fluids.

  3)- Convection- From one molecule to another in a solid.

• 1)- Radiation- Directly without using any medium.

  2)- Conduction- From one molecule to another in a solid.

  3)- Convection- By actual movement of molecules in fluids.

Choose the correct statement.

• Almost all cold objects radiate heat.

• There isn't any object which radiates heat.

• Almost all hot objects radiate heat.

Objects having ________________are____________of radiant heat.

• bright or white colour ; good conductors

• dull or black color ; good conductors

Handles of cooking vessels are made of ___________

• GOOD CONDUCTORS OF HEAT.

• BAD CONDUCTORS OF HEAT.

SELECT THE CORRECT STATEMENT.

• WHEN A SOLID IS HEATED, THE MOLECULES OF THE SOLID IN CONTACT WITH THE SOURCE OF HEAT START VIBRATING FASTER.

• WHEN A SOLID IS HEATED, THE MOLECULES OF THE SOLID IN CONTACT WITH THE SOURCE OF HEAT START VIBRATING SLOWER THAN USUAL.

• WHEN A SOLID IS HEATED, THE MOLECULES OF THE SOLID IN CONTACT WITH THE SOURCE OF HEAT DON'T EXPERIENCE ANY CHANGE AND VIBRATE NORMALLY.