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प्रश्न
Explain with an example to demonstrates that when a liquid evaporates, it takes heat from its surroundings.
उत्तर
If some spirit is poured on cotton wrapped around the bulb of a thermometer, the reading of the thermometer falls. This shows that cooling is produced when a liquid evaporates taking heat from surroundings.
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संबंधित प्रश्न
Why does our palm feel cold when we put some acetone or petrol or perfume on it?
What is evaporation?
State three factors which affect the rate of evaporation of a liquid.
Give two applications of evaporation.
Would you cool a bucket of water more quickly by placing it on ice or by placing ice in it ? Give reasons for your answer.
The evaporation of water increases under the following conditions :
The scientists now say that there are actually five states of matter A, B, C, D and E. The state A has a fixed volume but no fixed shape. The state B can be compressed very easily by applying pressure and state C has a fixed shape as well as a fixed volume. The state D is a mixture of free electrons and ions whereas state E is named after an Indian scientist and a famous physicist.
- Name the physical states (i) A (ii) B (iii) C (iv) D, and (v) E
- Name one substance belonging to state C which can directly change into vapours on heating. What is this process known as ?
- Name one substance which normally belongs to state B but whose solid form changes directly into gaseous state.
- Name the most common substance belonging to state A.
- Which state of matter makes the sun and other stars to glow ?
Can you suggest a method to collect water from sea water?
The rate of evaporation ______ with rising temperature.
The rate of evaporation is more when the surface area is greater.
