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प्रश्न
State the energy changes which take place when:
Water freezes in the freezing chamber of a fridge.
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उत्तर
The kinetic energy of water molecules is released in the form of heat energy.
संबंधित प्रश्न
Fill in the blank
An object falling freely from the roof of a multistorey building has ________ and _________ energy when halfway down the building.
Name the type of energy (kinetic or potential) possessed by the following:
Water flowing in a river.
Give one example to show that the sum of potential energy and kinetic energy remains constant if friction is ignored.
State two uses of solar cells.
MULTIPLE CHOICE TYPE:
The ultimate source of energy is:
(a) wood
(b) wind
(c) water
(d) sun
A hydroelectric power station takes its water from a lake whose water level is 50 m above the turbine. Assuming an overall efficiency of 40%, calculate the mass of water which must flow through the turbine each second to produce power output of 1 MW. (Take g = 10 m s−2).
Give three examples of bodies possessing kinetic energy.
State the energy changes which take place when:
A body released from rest from the top of a building.
Give one example when:
Mechanical energy to heat energy.
A body of mass 0.2 kg falls from a height of 10 m to a height of 6 m above the ground. Find the loss in potential energy taking place in the body. [g = 10ms−2]
