Energy

No. Energy       
1. The two kinds of energy possesed by an abject are:
2. a) Potential Energy b) Kinetic Energy
2. Energy possessed by an object by virtue of its position is called Potential Energy.
3. Energy possessed by an object by virtue of its movement is called the Kinetic Energy.
4. Potential Energy depends on mass and hight of the object.
5. Kinetic Energy depends on mass and Velocity of the object.
6. Heat Energy can be changed into other forms of energy. Some substances expand when they are heated. Some substances change their state when they are heated.
7. When heated liquids expand more than solids; and gases expand more than liquids.
8. There are three ways by which heat is transmitted from hot bodies to cool bodies. They are:
a) Conduction b) Convection c) Radiation
9. Flowing of heat from one place to another place without the movement of molecules is called conduction.
10. Conduction takes place only if two bodies touch each other and there is some difference in temperatures of the bodies.
11. Good conductors of heat are: Gold, Silver, Aluminium etc.
12. Air is also bad conductor of heat.
2. The process of going up of heat absorbed molecules and coming down of cool molecules to absorb heat is called convection of heat.
13. Convection of heat takes place only in liquids and gases.
14. The process of transmission of heat from one place to another place without medium is called radiation of heat.
15. Generally liquids and gases are bad conductors but mercury is a very good conductor.
16. Black substances obsorb heat fast and also lost fast.
17. Wood, Asbestos, Paper, Glass etc. are bad conductors of heat. They are called insulators.