Advertisements
Advertisements
प्रश्न
Differentiate between energy and power.
उत्तर
| Energy | Power | |
| 1. | The energy of a body is its capacity to do work. | The power of a source is the energy spent by it in 1s. |
| 2. | Energy spent does not depend on time. | Power spent depends on the time in which energy is spent. |
| 3. | S.I unit of energy is the joule (J). | S.I unit of power is watt (W) |
APPEARS IN
संबंधित प्रश्न
A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?
Derive a relationship between S.I. and C.C.S. unit of work
State the S.I. unit of work and define it.
A water pump raises 50 litres of water through a height of 25 m in 5 s. Calculate the power of the pump required.
(Take g = 10 N kg-1 and density of water = 1000 kg m-3)
A box of weight 150 kgf has gravitational potential energy stored in it equal to 14700 J. Find the height of the box above the ground. (Take g = 9.8 N kg-1)
Write the formula for work done on a body when the body moves at an angle to the direction of force. Give the meaning of each symbol used.
Name five appliances or machines which use an electric motor.
Draw a neat labeled diagram to show the direction of two forces acting on a body to produce rotation in it. Also mark the point about which rotation takes place.
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?
Calculate the amount of work done by a child carrying a bag of 20 kg when he moves a distance of 40 m in
(a) Vertical direction, and
(b) Horizontal direction
Define force. Is force a scalar or a vector quantity?
Name two places in India where electricity is generated from nuclear power plants.
What is the difference between renewable and non-renewable resources?
A coolie is pushing a box weighing 1500 N up an inclined plane 7.5 m long on to a platform, 2.5 m above the ground.
(i) Calculate the mechanical advantage of the inclined plane. (ii) Calculate the effort applied by the coolie.
(iii) In actual practice, the coolie needs to apply more effort than what is calculated. Give one reason why you think the coolie needs to apply more effort.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A donkey is carrying a load on its back.
A uniform chain of length 2 m is kept on a table such that a length of 60 cm hangs freely from the edge of the table. The total mass of the chain is 4 kg. What is the work done in pulling the entire chain on the table?
State whether work is done or not, by writing yes or no, in the following case:
A man pushes a wall.
