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प्रश्न
Relate 1 KWh (kilowatt hour) with joule.
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उत्तर
1 KWh = 1 KW × 1 h = 1000 W × 3600s = 36,00,000 J.
संबंधित प्रश्न
When a body moves in a circular path, how much work is done by the body? Give reason.
(Hint: The body is acted upon by the centripetal force.)
Give an example when work done by the force of gravity acting on a body is zero even though the body gets displaced from its initial position.
What are the S.I. and C.G.S units of work? How are they related? Establish the relationship.
State the factors on which moment of force about a point depends.
What is a centripetal force?
How much force is applied on a body when 150 J of work is done in displacing the body through a distance of 10 m in the direction of the force?
A pump is used to lift 600 kg of water from a depth of 75 m in 10s. Calculate:
- The work done by the pump,
- the power at which the pump works, and
- The power rating of the pump if its efficiency is 40%. (Take g = 10m s-2).
`["Hint" : "Efficiency" = "useful power"/"power input"]`
A bullet fired against a window glass pane makes a hole in it without any cracks while a stone striking the same glass pane smashes it; explain with reason.
A man raises a box of mass 50 kg to a height of 2 m in 20 s, while another man raises the same box to the same height in 50 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1
