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प्रश्न
Why does the bottom of a lake not freeze in severe winter though the surface is all frozen?
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उत्तर
Lakes don’t completely freeze because the ice (and eventually snow) on the surface acts to insulate die water below. To freeze water into ice, a large quantity of heat is to be withdrawn. This heat cannot be
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संबंधित प्रश्न
Match the following
| Column A | Column B |
| 1. mercury | 1. insulator |
| 2. wood | 2. water from 0°C to 4°C |
| 3. Aluminum | 3.absorbs |
| 4. contracts | 4.conductor |
| 5.black surface | 5. Thermometer |
What will absorb heat?
Glass vessel
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The water in the black can becomes ______ than that in a white can after exposure to the sun.
Black color is a ______ absorber of heat.
Assertion: Small gaps left between railway lines.
Reason: It allows for the contraction of rails during summer.
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Which of the following is true?
Match the following:
| Column A | Column B | ||
| 1. | Heat | a. | Heat gained or lost in the change of state without any change in temperature |
| 2. | m × L. | b. | Heat gained or lost when there is no change of state |
| 3. | Temperature | c. | Form of energy |
| 4. | m × s × t | d. | SI unit of specific latent heat |
| 5. | J/Kg | e. | degree of hotness or coldness |
