Question

Anyone have notes of Chapter 14 SOURCES OF ENERGY
SUB.-Science

Answer 1

Renewable and Non-Renewable Source of Energy

Renewable source of energy is the energy source which can be replenished in short period. Example Solar energy, hydropower
An energy source which cannot be recreated in short period is categorized as non-renewable source of energy. Example Fossil Fuel-oil, natural gas, Coal 

Good Sources of Energy

A good source of energy has following characteristics:
(i) It could do a large amount of work per unit volume or mass.
(ii) It would be easily accessible.
(iii) it would be easy to store and transport.
(iv) It would be economical.

Conventional and Non -Conventional Source of Energy

Sources of energy which has been in use from Centuries are called the conventional source of energy. Example Wood,Coal,Petrol,hydropower
Source of energy which we have started using in recent times is called Non-conventional energy sources Example Nuclear energy, Geothermal energy, Solar energy, Ocean tides

Fossils Fuels

-Fossils fuel are the remains of the pre-historic animal and plants buried under the earth millions of years ago.bv
-They are non-renewable sources of energy
- Since fossils fuels from plants and animals and they get energy from Sun, so their ultimate source of energy is Sun
Example
Coal, Petroleum products



Turbine

A turbine is device that rotates when steam, water or wind false on its blades. The turbine turns the shaft of the electric generator and then electricity is produced 

Thermal Power Plants

Thermal power plants burn fossils fuel like coal which heat up the water to produce steam and Steam is used in Turbine to generate electricity.
The term thermal power plant is used since fuel is burnt to produce heat energy which is converted into electrical energy


Hydropower Plants

In hydropower plants,kinetic energy of the flowing water or the potential energy of the water at height is used to turn the turbine and generate electricity.
To produce hydel electricity, high-rise dams are constructed on the river to obstruct the flow of water and thereby collect water in larger reservoirs. The water level rises and in this process the kinetic energy of flowing water gets transformed into potential energy. The water from the high level in the dam is carried through pipes, to the turbine, at the bottom of the dam


Biomass

Biomass is any organic matter from which we get energy on the renewable basis. It includes wood, Agricultural residues, animal excreta, wastes from food processing.Two important Biomass energy sources are given below

Charcoal

Charcoal is produced by burning wood in an insufficient supply of water. This method is called destructive distillation of wood. Charcoal burns without flames, is comparatively smokeless and has a higher heat generation efficiency

Biogas

Cow-dung, various plant materials like the residue after harvesting the crops, vegetable waste and sewage are decomposed in the absence of oxygen to give bio-gas. Anaerobic micro-organisms that do not require oxygen decompose or break down complex compounds of the cow-dung slurry. The process is called anaerobic digestion
Since the starting material is mainly cow-dung, it is popularly known as ‘gobar-gas’
Bio-gas contains up to 75% methane,23% Carbon dioxide and 2% other gases. It burns without smoke, leaves no residue like ash in wood, charcoal and coal burning. It is an excellent fuel



Wind Energy and Wind mill

Unequal heating of the landmass and water bodies by solar radiation generates air movement and causes winds to blow. The wind contains the kinetic energy. This kinetic energy is used the windmill to do some mechanical work.
A windmill is a device in which kinetic energy of the wind is used to rotates a set of blades and rotational energy of the blades is used to do some mechanical work and power the turbine to generate electricity


Solar Energy

Solar energy is the energy of Sun. The earth receives a huge amount of energy from the sun. Traditionally We have been solar energy for drying clothes and grains, make salt from sea water


Solar cooker

Solar cooker is a device which is used to cook food by using solar energy. Solar cookers and solar water heaters are based on the facts that A black surface absorbs more heat as compared to a white or a reflecting surface under identical conditions
Solar cooker is having box type structure and its internal surfaces are coloured with black colour. Solar cookers are covered with a glass plate. Which traps heats to go out from box and shows greenhouse effect. A plane mirror is also used to focus the rays of the light. The food which need to be cooked ins kept inside the box and temperature around 140o C in summer in 2-3 hour and cooked the food