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प्रश्न
______ of heat does not require a medium.
विकल्प
radiation
white
conduction
blue
convection
bad conductor
good conductor
black
reflection
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उत्तर
Convection of heat does not require a medium.
Explanation:
In convection, when the temperature of a substance increases due to heat, its molecules move faster, causing them to rise. As a result, cooler and denser objects sink to the bottom. This process is possible only when a substance (liquid or gas) is present, as it requires the mobility and movement of molecules.
संबंधित प्रश्न
No medium is required for transfer of heat by the process of ______.
Look at Figure. Mark where the heat is being transferred by conduction, by convection and by radiation.
A wooden spoon is dipped in a cup of ice cream. Its other end ______.
Write true or false for a given statement.
On touching a lump of ice, we feel cold because some heat passes from our body to the ice.
Select the correct alternative
In the process of convection, heat travel
State the direction of heat transfer by way of convection.
Why is the freezing chest in a refrigerator fitted near its top?
How does a fever get lowered by putting a cold compress on the forehead of a patient?
Explain which mode of heat transfer causes sea breezes and land breezes.
Match the items in column-I to the items in column-II
| Column-I | Column-II | ||
| 1. | Linear expansion | (a) | change in volume |
| 2. | Superficial expansion | (b) | hot body to cold body |
| 3. | Cubical expansion | (c) | 1.381 X 10-23 JK-1 |
| 4. | Cubical expansion | (d) | change in length |
| 5. | Boltzmann constant | (e) | change in area |
