SOURCES OF ENERGY
One form of energy can be
converted to another. E.g.
o When a plate hits the ground, potential energy is
converted to sound energy.
o In a burning candle, chemical energy is converted to heat
energy and light energy.
But these energy forms
cannot be reversed again to the previous forms.
When hot water is kept in
room temperature, the heat energy is lost to the environment. But this lost
energy cannot be re-collected to heat the water again.
Dissipated usable energy cannot
be used again.
WHAT
IS A GOOD SOURCE OF ENERGY?
Various sources of energy
are used for doing work.
Muscular energy to carry out physical work, electrical energy for
running various appliances, chemical energy for cooking food or running
a vehicle all come from some sources.
Various fuels for cooking
include Electricity, LPG, Wood, Coal, solar cooker, etc.
A good fuel is
easily available, efficient, cheap, clean, and easy to use producing no or
least pollutants. E.g. In home, LPG &
electricity are preferred as they are highly efficient, smokeless, easily
available and easy to use.
Selection of fuels also
depends on the work to be done and the amount of energy needed.
Advantages of a good source of energy:
o Do huge work per unit volume or mass.
o Easily accessible.
o Easy to store and transport.
o Economical.
