Heat

 

Heat - Heat is the form of energy which sensation of hotness and coldness

Temperature- Temperature is the measurement of average energy of molecular motion in a substance. 

Heat transfer- The Energy is flow from higher Temperature body to lower temperature body.

Unit of Heat- SI unit of Heat is Joule

Calorie- It is a traditional unit of Heat. One Calorie is defined as the amount of heat required to raise the temperature if 1 g if water by 1 Degree Celsius. 

Note- 1 Joule= 0.24 Calorie

Effect of Heat

1. Change in temperature
2. Change in state of matter

 

Evaporation

The change of a substance from the liquid state to its gaseous state by absorbing heat from the surrounding at any temperature below its boiling point is called evaporation.

Factor affecting Evaporation  

1. Surface area
2. Temperature of surrounding
3. Temperature of the substance
4. Nature of liquid
5. Wind Speed
6. Humidity

 

 

Boiling- The process in with Liquid change into vapors state at a particular temperature by absorbing heat is called boiling or vaporization.

Boiling point- The fixed temperature at which liquid states boil  is known as its boiling point.

Factor affecting boiling

1. Nature of liquid
2. Atmospheric pressure
3.Presence of impurities

Thermal Expansion- When the temperature of a substance is increased, it results in expansion of the Substance. This property is called Thermal expansion

Thermal Expansion in Solid

Linear Expansion= Increase in length
Superficial expansion- Increase in Area
Cubical Expansion= Increase in Volume

Application in daily life

1. Gap Between railway tracks
2. Electric wire laid loose leaving scope of expansion and contraction