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प्रश्न
State the S.I. unit of energy.
State the SI unit of electrical energy.
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उत्तर
Joule (J)
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संबंधित प्रश्न
A coolie does no work against the force of gravity while carrying a luggage on a road.
Work is said to be done by a forte only when ................
The S.I. unit of energy is .............
Give reasons for the following. No work is done if a man is pushing against a wall.
A boy weighing 25 kgf climbs up from the first floor at height 3 m above the ground to the third floor at height 9m above the ground. What will be the increase in his gravitational potential energy? (Take g = 10 N kg -1)
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A boy throws a rubber ball vertically upwards. What type of work, positive or negative, is done : by the force applied by the boy?
(a) by the force applied by the boy?
(b) by the gravitational force of earth?
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(i) P.E. maximum,
(ii) K.E. maximum,
(iii) P.E. = K.E.?
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(a) during the motion
(b) at the highest point?
A 100 W electric lamp emits energy in the form of light at the rate 10 J per second. What percentage of electric energy does the lamp transform into light energy?
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Name two places in India where electricity is generated from nuclear power plants.
A truck driver can load oil drums into the back of the truck by pushing them up a sloping plank, or by lifting them directly. Each drum has a mass of 80 kg, the plank is 3 m long, and the back of the truck is 0.8 m above the ground.
(i) How much force would be needed to lift a drum into the truck directly/without using the plank? (Take g = 10 m/s2)
(ii) How much energy would be required in lifting the drum into the truck without the plank?
(iii) If the force needed to push the drum up the plank is 300 N, why is this less than the answer to part (i)?
(iv) When the truck is loaded, the driver drives off. List the major energy changes that take place in moving the truck.
(v) The driver has to stop at the factory gates. What happens to the kinetic energy of the truck?
