Page 244 - New Medley 4 Semester 2 PDF (Merged)
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Knowledge Zone
The Bhakra Nangal Dam situated across the river Sutlej (or Satluj) in Himachal Pradesh is
the largest dam in India and the highest gravity dam in the world.
1 • Remembering
Give one word answer.
1. The force used by a man in lifting a bag.
2. The force that makes an apple fall on the ground.
3. The energy obtained from the sun.
4. The energy of flowing water.
ENERGY CONVERSIONS
Energy can be changed from one form to another. Let’s see how!
The solar energy is used by green plants to make food by the process of
photosynthesis. In photosynthesis, the solar energy is converted into chemical
energy. When we eat plants or their parts, the chemical energy of food is
converted into muscular energy.
The solar energy can also be converted into electrical energy with the help
of solar cells.
Solar cooker and solar heater convert
the energy of the sun into heat energy
to cook food and provide hot water
respectively.
When a bulb is lighted, the electrical
energy is converted into light energy. Solar cells in a solar panel A lighted bulb
ENERGY CRISIS
Coal, petrol, diesel and Compressed Natural Gas
(CNG) are the main sources of energy. These are
called fossil fuels. These have been formed from
the remains of dead plants and animals which
got buried under the layers of earth millions of Coal–A non-renewable source of energy
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