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प्रश्न
Name the material commonly used for the manufacturing of solar cells.
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उत्तर
Silicon and Gallium. Solar cell produces d.c. current. State whether a solar cell produces a.c. or d.c. current.
संबंधित प्रश्न
Name a common device where a gear train is used
The S.I. unit of energy is .............
A boy of weight 40 kgf climbs up the 15 steps, each 15 cm high in 10 s and a girl of weight 20 kgf does the same in 5 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1.
How much energy is gained by a box of mass 20 kg when a man, carrying the box waits for 5 minutes for a bus?
A boy tries to push a truck parked on the roadside. The truck does not move at all. Another boy pushes a bicycle. The bicycle moves through a certain distance. In which case was the work done more : on the trick or on the bicycle? Give a reason to support your answer.
Each of the following statement describes a force acting. Which force is causing work to be done?
Name the physical quantity whose SI unit is Nm.
Fill in the boxe to show the corresponding energy transformation.
In the following case write yes, if the work is being done and no if no work is being done.
A boy climbing up a staircase.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
Food grains are getting dried in the sun.
