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TNPSC Science Notes - 6th Standard - Types of Energy

Types of Energy
6th Std Science Series - 3

The Definition

The definition of Energy as the capacity ability to do work. The unit of Energy is Joule. 

There are many different types of Energy
    1. Mechanical Energy, 
    2. Chemical Energy, 
    3. Light Energy, 
    4. Sound Energy,
    5. Electrical Energy, 
    6. Heat Energy and
    7. Wind Energy. 
1. Mechanical Energy:

Mechanical energy is the energy possessed by an object due to its movement or position. There are two types of mechanical energy.  
  • Potential energy  
  • Kinetic energy
Potential energy:  
  • The energy possessed by an object by virtue of its position or configuration is called potential energy. 
Kinetic energy:  

The energy possessed by a body by virtue of its motion is called kinetic energy.
  • Potential energy and kinetic energy are inter-convertible. This property is used to generate electricity in  hydro-electric power stations.
  • Water is stored in a dam, the stored water contains potential energy. This water is allowed to  flow down, it changes into kinetic energy. This kinetic energy of water is used to rotate the turbines and generate electricity. 
  • The mechanical energy of the rotation of turbines is converted into electrical energy in a generator.
Uses of Mechanical Energy:
  • Mechanical energy can bring  a moving body to rest or can make a  body at rest to move.
  • Using wind energy, we can generate  electricity through windmills. 
2. Chemical Energy
  • Energy that is stored in the bonds of chemical compounds is called chemical energy. Chemical energy is released during a chemical reaction, often in the form of heat and light.
  • The food we eat undergoes chemical reaction and releases energy to enable us to work.
Uses of Chemical energy
  • The Chemical Energy stored in the food of plants and animals is used for their growth and function.
  • A Battery or an electric cell converts chemical energy into electrical energy.
  • While using fuels, chemical energy is converted into heat energy and light energy.
3. Electrical energy
  • In an electric bulb, electrical energy is converted into light energy and in an electric fan, electrical energy is converted into mechanical energy. In a windmill, the wind energy (kinetic energy) is converted into electrical energy.
Uses of Electrical energy:
  • In industries, electrical energy is used to operate machines and is also used in telecommunication.
  •  In cities, electrical energy is used to run electric trains.
4. Heat Energy
  • The primary source of heat energy is the Sun. The chemical energy stored in wood, kerosene and LPG is converted into heat energy. 
Uses of Heat Energy:
  • We get rain due to evaporation of waste from water bodies. It is because of the heat energy from the Sun.
  • In a thermal power station, of electricity is generated from the heat energy obtained by burning coal.
  • In an electric stove, electric iron  etc., electrical energy is converted into heat energy.
5. Solar Energy 
  • The energy obtained from the Sun is called solar energy. 
Uses of Solar energy 
  • Solar energy is directly used in solar heater, solar cooker etc.,
  • Solar cells are used in artificial satellites, watches, calculators and is used to operate solar vehicles.
The Law of Conservation of Energy
  • Energy can neither be created nor be destroyed, but can be transformed from one form into another. This is called the Law of Conservation of Energy.
Exam Key Points: 
  • "Heat is a form of  energy" - James Joule.  The unit of energy (joule) is named after him.
  • In Mettur and Bhavani Sagar, electricity is generated using  hydroelectric power.
  • Wind mill- (Electric power generation) at Kayathar (Thirunelveli),  Aralvoimozhi (Kanyakumari) and also in Coimbatore, Tirupur Districts
  • ln 212 BC, the Greek scientist, Archimedes used magnifying glasses to burn Roman warships with solar energy.
  • In Tamilnadu, at Neyveli and Ennore,  thermal power stations, coal is burnt to generate electricity. Here the chemical energy of coal is first converted into heat energy and then into electrical energy.
  • The loudspeaker converts electrical energy into sound energy. 
  • When water stored at a height flows down,  its  potential energy is converted into kinetic energy, which rotates the turbine of a generator and generates electrical energy.
  • When wood, charcoal, petrol, diesel and other fuels are burnt, chemical energy is converted into heat energy.
  • During photosynthesis, plants convert light energy from the sun into chemical energy and store it.
  • In electric doorbells and horns of automobiles, electrical energy is converted into sound energy.
  • In a torch light, the chemical energy of  the cell is first  converted into electrical energy and then into light energy.
Important Questions and Answers

1. Energy required to dry clothes quickly is  ______.

 a) solar energy                   
 b) sound energy
 c) kinetic energy  
 d) potential energy

 Answer: a) solar energy  

2. "Heat is a form of energy". This was discovered by _______.

a) Volata
b) James Joule
c) Thomas Alwa Edison
d) Galileo

Answer: b) James Joule

3. Which of the following requires electrical energy?

a) windmill                           
b) industry
c) bicycle                             
d) parachute

Answer: b) industry

4. The _______energy cannot be used to run vehicles.

a) solar                     
b) chemical
c) electrical                
d) sound  

Answer: d) sound

5.  When charcoal is burnt, chemical energy is converted into______energy.

a) heat                          
b) sound 
c) mechanical                
d) solar  

Answer: a) heat    

6. Energy obtained by wind energy in wind farms - Electrical Energy

7. Energy possessed by a rustling leaf -  Chemical Energy

8. Energy possessed by a person landing from a parachute - Kinetic Energy of Wind 

9. Energy produced by rubbing the two palms of your hands - Heat Energy

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