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Question
Answer the following question.
How heat transfer occurs through radiation in absence of a medium?
Solution
- All objects possess thermal energy due to their temperature T(T > 0 K).
- The rapidly moving molecules of a hot body emit EM waves travelling with the velocity of light. These are called thermal radiations.
- These carry energy with them and transfer it to the low-speed molecules of a cold body on which they fall.
- This results in an increase in the molecular motion of the cold body and its temperature rises.
- Thus transfer of heat by radiation is a twofold process-the conversion of thermal energy into waves and reconversion of waves into thermal energy by the body on which they fall.
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