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प्रश्न
Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations.
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उत्तर
Water in the form of ice has low energy since water freezes at a lower temperature. When ice comes in contact with body it draws heat from the body and gives cooling effect. In case of steam, the water molecules have high energy. The high energy of steam is transformed as heat and may cause severe burns.
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संबंधित प्रश्न
The temperature at which a solid convert into a liquid is called its .........
Molecules of a substance are always in a state of............ and so they possess .............
Differentiate between melting point ,giving atleast one example of each.
State the melting point of ice.
The fixed temperature at which matter changes state from solid to liquid is called ______.
Analogy:
Melting: ice into water on heating,
freezing: _______.
A student heats a beaker containing ice and water. He measures the temperature of the content of the beaker as a function of time. Which of the following (Fig. 1.1) would correctly represent the result? Justify your choice.
A glass tumbler containing hot water is kept in the freezer compartment of a refrigerator (temperature < 0°C). If you could measure the temperature of the content of the tumbler, which of the following graphs (Fig.1.2) would correctly represent the change in its temperature as a function of time.
Sweating causes cooling because water has a ______.
A change of state is a change of a substance from ______.
