Advertisements
Advertisements
प्रश्न
Define the term efficiency of a machine.
Advertisements
उत्तर
The ratio of the work done by the machine to the work done on the machine is called the efficiency of a machine
Efficiency =`"Output energy"/" Input energy"`
(Work done by a machine is called the output energy and the work done on a machine is called the input energy.)
APPEARS IN
संबंधित प्रश्न
State two factors on which the potential energy of a body at a certain height above the ground depends.
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 |
Answer the following in a word or two or in a sentence.
Write the formula for calculating the efficiency of a machine.
Define the term 'watt'.
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?
The capacity that an object has for doing work is called ______.
Which one of the following requires wind energy?
Write the type of energy.
