Advertisements
Advertisements
प्रश्न
What is energy?
Advertisements
उत्तर १
The ability or capacity to do work is called energy.
उत्तर २
Energy is defined as the capacity to do work. S.I unit of work is Joule.
संबंधित प्रश्न
Write true or false of the following statement.
In an electric fan, electrical energy changes into the mechanical energy.
Fill in the blank
An electric fan converts electrical energy into ______ energy.
Fill in the blank
Cooking gas converts _______ energy into heat energy.
Fill in the blank
The ability to do work is called ______
Fill in the blank
The S.I.unit of energy is ______
Match the following:
| Column A | Column B |
| (a) Needle | (1) class II lever |
| (b) Doorknob | (2) inclined plane |
| (c) Ramp | (3) Class I lever |
| (d) Lemon crusher | (4) Wheel and axle |
| (e) Seesaw | (5) wedge |
Define the term efficiency of a machine.
Give a reason for the following.
The efficiency of a machine is always less than 100%.
Name the quantity whose unit is :
(a) kilowatt
(b) kilowatt-hour
What is the common name of '1 kWh' of electrical energy?
A cell converts one form of energy into another form. Name the two forms.
- Take two aluminium channels of different lengths.
- Place the lower ends of the channels on the floor and hold their upper ends at the same height.
- Now take two balls of the same size and weight and release them from the top end of the channels. They will roll down and cover the same distance.
- At the moment of releasing the balls, which energy do the balls have?
- As the balls roll down which energy is converted into which other form of energy?
- Why do the balls cover the same distance on rolling down?
Note: The question is wrong. It should be "Why do the balls cover the same distance after rolling down"? - What is the form of the eventual total energy of the balls?
- Which law related to energy does the above activity demonstrate? Explain.
If the energy of a ball falling from a height of 10 metres is reduced by 40%, how high will it rebound?
We make useful objects from a variety of substances. Another use of substances is that we get energy from some of them.
When we have run a long distance, we feel tired. We have to stop. Why is that?
Find out the form of energy possessed by the following thing.
A rock on the top of a hill
What energy transfer happen in a car engine?
Which one of the following is not the unit of energy?
The weight of a person on planet A is about half that on the earth. He can jump up to 0.4 m in height on the surface of the earth. How high he can jump on planet A?
