Physics
State the energy changes that occur in the following:
(i) The unwinding of a watch spring.
(ii) Burning coal while operating a steam engine
(iii) Lighting of a torch bulb.
(iv) An electric generator (or dynamo).
Answer
(i) During the unwinding of a watch spring, the potential energy changes into kinetic energy.
(ii) In a steam engine chemical energy of coal first changes into heat energy which is transferred to steam. Then the heat energy of steam changes into mechanical energy which causes the train to move.
(iii) When torch bulb is lighted, chemical energy of batteries change into light and heat energy.
(iv) In an electric generator (dynamo) mechanical energy changes into electrical energy.
Related Questions
Name the form of energy which a wound up watch spring possesses.
Name the type of energy (kinetic or potential) possessed by the following:
(i) A moving cricket ball.
(ii) A stone at rest on the top of a building.
(iii) A compressed spring.
(iv) A moving bus.
(v) A bullet fired from a gun.
(vi) Water flowing in a river.
(vii) A stretched rubber band.
A ball is made to fall freely from a height. State the kind/kinds of energy possessed by the ball when it is:
(a) at the highest point
(b) just in the middle
(c) at the ground.
State two factors on which the potential energy of a body at a certain height above the ground depends.