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प्रश्न
What type of clothes should we wear in summer ? Why ?
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उत्तर
In summer, we should wear cotton clothes or white clothes because cotton absorbs sweat easily and exposes it to the air for evaporation. Evaporation of this sweat keeps our body cool. In addition, white colour reflects sunlight, keeping the heat away from the body.
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संबंधित प्रश्न
How does water kept in an earthen pot (matka) become cool during summer?
What produces more severe burns, boiling water or steam?
Explain with an example to demonstrates that when a liquid evaporates, it takes heat from its surroundings.
Explain why in hot summer days water remains cool in earthen pots.
Which produces more severe burns : boiling water or steam ? Why ?
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 ?
How is humidity measured?
Comment on the following statements:
Rate of evaporation of an aqueous solution decreases with increase in humidity.
The rate of evaporation ______ with rising temperature.
