Heat Radiation and Temperature – Rankers Physics

Heat Transfer - Radiation: Practice Problem & Solution

Assertion (A): Bodies radiate heat at all temperature. Reason (R): Rate of radiation of heat is proportional to the fourth power of absolute temperature.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Heat Transfer - Radiation. Understanding the underlying formula is key to arriving at the correct answer below:

All bodies above 0 K radiate thermal energy. The Stefan-Boltzmann law states that the rate of radiation P is proportional to the fourth power of absolute temperature \(T^4\), i.e., \(P \propto T^4\). This law confirms that radiation occurs at any temperature above absolute zero and quantifies it. Thus, R explains A.

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