Advertisements
Advertisements
प्रश्न
Energy can exist in several forms and may change from one form to another. State the energy changes that occur in the burning of a match stick.
Advertisements
उत्तर
Chemical energy changes into heat and light energy.
APPEARS IN
संबंधित प्रश्न
State the energy changes in the following while in use An electric bulb.
State the energy changes in the following while in use A loudspeaker .
State the energy changes that occur in the following :
The unwinding of a watch spring.
State the energy changes that occur in the following :
Burning coal while operating a steam engine.
Energy can exist in several forms and may change from one form to another. State the energy changes that occur in photosynthesis in green leaves.
State the energy changes in the following case while in use:
Microphone
A boy is moving on a straight road against a frictional force of 5 N. After travelling a distance of 1.5 km he forgot the correct path at a roundabout (Fig. 11.1) of radius 100 m. However, he moves on the circular path for one and half-cycle and then he moves forward up to 2.0 km. Calculate the work done by him.
Four men lift a 250 kg box to a height of 1 m and hold it without raising or lowering it.
(a) How much work is done by the men in lifting the box?
(b) How much work do they do in just holding it?
(c) Why do they get tired while holding it? (g = 10 m s–2)
Define watt. Express kilowatt in terms of joule per second. A 150 kg car engine develops 500 W for each kg. What force does it exert in moving the car at a speed of 20 ms–1?
In an electric cell while in use, the change in energy is from ______.
