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प्रश्न
What is evaporation? Why does it cause cooling?
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उत्तर
Evaporation is the phenomenon of a change of a liquid into vapour without raising the temperature. Evaporation needs energy for phase change from liquid to gases. As water evaporates off your skin, it absorbs energy(heat) from the body to make the phase change to gas thus cooling the body.
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संबंधित प्रश्न
Draw a neat labelled diagram of a laboratory thermometer.
Two bodies at different temperatures are placed in contact with each other. State the direction in which heat flows.
Convert the following temperature into Fahrenheit scale:
-400C
Explain the following:
In a solid, heat is not transferred by the process of convection.
The dimensions of a substance are increased if the temperature of the substance is decreased.
Assertion (A): 0 °C = 273.16 K. For our convenience we take it as 273 K after rounding off the decimal.
Reason (R): To convert a temperature on the Celsius scale we have to add 273 to the given temperature.
______ determines the direction of the flow of heat.
