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प्रश्न
उत्तर
Electric power is the rate at which an electric circuit transfers electrical energy per unit of time.
The SI unit of power is the watt, one joule per second
`P = "work"/"time in Secs" = w/t`
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संबंधित प्रश्न
Differentiate between energy and power.
A body of mass 5 kg falls from a height of 10 m to 4 m. Calculate:
The loss in potential energy of the body,
A vessel containing 50 kg of water is placed at a height 15 m above the ground. Assuming the gravitational potential energy at ground to be zero, what will be the gravitational potential energy of water in the vessel? (g = 10 m s-2)
A car is running at a speed of 15 km h-1 while another similar car is moving at a speed of 45 km h-1. Find the ratio of their kinetic energies.
Fill in the blank with suitable word :
The work done on a body moving in a circular path is __________
The work done on an object does not depend on the :
A girl weighing 400 N climbs a vertical ladder. If the value of g be 10 m s−2, the work by her after climbing 2 m will be :
Choose one or more correct alternatives.
Joule is the unit of ______.
- force
- work
- power
- energy
Does the earth move around the sun with a uniform velocity?
Give two examples of work done.
An object is dropped from a height H. when is its
(i) P.E. maximum,
(ii) K.E. maximum,
(iii) P.E. = K.E.?
Give an example
Light energy changes to electrical energy.
A coolie, with a load of 30 kg on his head, walks on the platform. If he walks a distance of 60 m, what is the work done by him?
What should be the characteristic of a source of energy?
How long should an electric motor, of power 2 H.P. operate, so as to pump 5 m3 of water from a depth of 15m. [Take g = 10 N kg−1]
A girl of mass 40 kg runs a height of 80 stairs, each 25 cm high with a load of 20 kg on her head in 25 sec. If g is 10 m/s2, find:
(i) Gravitational force acting on the girl.
(ii) Work done by her.
(iii) Useful work done by her.
(iv) Her power in watt.
What is work?
