CBSE Class 10 Physics Sources of Energy Notes. Learning the important concepts is very important for every student to get better marks in examinations. The concepts should be clear which will help in faster learning. The attached concepts made as per NCERT and CBSE pattern will help the student to understand the chapter and score better marks in the examinations.
CHAPTER – 14
SOURCES OF ENERGY
ENERGY: - Whenever a body is capable of doing work, the body is said to possess energy. Thus energy is defined as the ability of a body to do work and the amount of energy possessed by a body is equal to the amount of work it can do when its energy is released.
Energy comes in different forms and one form can be converted 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.
Units of energy: - On S.I. system, energy is measured in the units of joules or in calories, and on C.G.S. system in ergs. However, the commercial unit of energy is kilowatt-hour. The energy is said to be one kilowatt-hour, when a body consumes one kilowatt of energy in one hour.
Sources of energy : a source of energy is that which is capable of providing enough useful energy at a steady rate over a long period of time.
A good source of energy should be :
i) Safe and convenient to use, e.g., nuclear energy can be used only by highly trained engineers with the help of nuclear power plants. It cannot be used for our household purposed.
ii) Easy to transport, e.g., coal, petrol, diesel, LPG etc. Have to be transported from the places of their production to the consumers.
iii) Easy to store, e.g., huge storage tanks are required to store petrol, diesel, LPG etc.
Characteristics of an ideal or a good fuel:
ØIt should have a high calorific or a heat value, so that it can produce maximum energy by low fuel consumption.
ØIt should have a proper ignition temperature, so that it can burn easily.
ØIt should not produce harmful gases during combustion.
ØIt should be cheap in cost and easily available in plenty for everyone.
ØIt should be easily and convenient to handl Øe, store and transport from one place to another.
ØIt should not be valuable to any other purpose than as a fuel.
ØIt should burn smoothly and should not leave much residue after its combustion.
INTEXT QUESTIONS PAGE NO. 243
1. What is a good source of energy?
Ans. A good source of energy fulfils the following criteria:
· It produces a lot of heat per unit mass.
· It does a huge amount of work per unit mass.
· It is easily accessible.
· It is easy to store and transport.
· It is economical.
· It produces less amount of smoke.
2. What is a good fuel?
Ans. A good fuel produces a huge amount of heat on burning, does not produce a lot of smoke, and is easily available.
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