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प्रश्न
Why does our palm feel cold when we put some acetone (or perfume) on it ?
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उत्तर
Our palm feels cool when we put acetone over it because acetone takes up the latent heat of vaporisation to change into vapour from our palm.
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संबंधित प्रश्न
Why are we able to sip hot tea or milk faster from a saucer than a cup?
Why are volatile liquids such as alcohol and spirit stored in tightly closed bottles?
Why is cooling produced on evaporation of a liquid?
Explain with an example to demonstrates that when a liquid evaporates, it takes heat from its surroundings.
A patient suffering from high fever is advised to put wet clot strips on his forehead. Why?
Define the following terms Condensation
Why are we able to sip hot tea or milk faster from a saucer rather than from a cup ?
Why does evaporation cool a liquid ?
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 ?
Comment on the following statements:
Rate of evaporation of an aqueous solution decreases with increase in humidity.
