Physics notes: SOURCES OF ENERGY For ALP Stage-2 exam 2018 (PART 1)

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Energy comes in different forms and energy can be converted from one form to another. For example; if we drop a plate from a height, the potential energy of the plate is converted mostly to sound energy when it hits the ground.

Characteristics of a good source of energy:
-It should be able to do large amount of work for each unit of mass or volume.
-It should be easily accessible.
-It should be easily transported.
-It should be economical.
-Less combustile 
Source of Energy can be divided into 2 types-
1. Conventional                  2. Non- conventional
1. Conventional Sources of Energy:
These sources of energy are also called non renewable sources.These sources of energy are in limited quantity except hydro-electric power and have been in use since a long time. For e.g Thermal power plant, Fossil fuels(Coal, Petroleum), Geothermal energy and hydro power plants. 
A. FOSSIL FUELS: Millions of years ago plants and animals tissues got buried under the ground and were subjected to high temperature and pressure. Coal is a fossil fuel which was formed due to subjection of plant tissues under high pressure and temperature. While petroleum is obtained from the remains of animals between sedimentary rocks.They are non-renewable sources of energy so we need to conserve them. 

Uses of fossil fuel-
– In cooking- LPG, coal
-In vehicles- Petrol, diesel
-To produce electricity in thermal power plants
Disadvantages-
– Causes air pollution as burning fossil fuels result in the release of poisonous gases like sulphur into the air
-Results in release of gases that cause acid rain, which in turn may lead to soil and water pollution
B. THERMAL POWER PLANT
It is a plant in which electricity is produced from fossil fuels mainly coal.Electricity transmission is very efficient.
First, the coal is burnt into the furnace of steam boiler. High pressure steam is produced in the boiler. In turbine, this steam force rotates the turbine blades.As the turbine turns, it causes the generator to do its work and create electricity. 
C. HYDRO POWER PLANT
Hydro power plants convert the potential energy of falling water into electricity. Dams are contructed to collect water flowing in high altitude rivers.
Around 25% of our country’s energy requirement is met by Hydro power plants.  
Advantages-
– No environmental pollution
– Provides irrigation facilities to rural areas
– Renewable source of energy
Disadvantages
– Dams can only be contructed in high terrain areas
– Large areas of agricultural land and human habitation are to be sacrificed as they get submerged.
– Large ecosystem are destroyed
– Vegetation which is submerged rots under anaerobic conditions and gives rise to large amount of methane which is also a green house gas.