Question:medium

Which law governs radiation heat transfer, relating emissive power to the fourth power of absolute temperature?

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Remember that radiation heat transfer scales with absolute temperature to the fourth power ($T^4$). Always convert Celsius temperatures to Kelvin first!
Updated On: Jul 4, 2026
  • Newton's Law of Cooling
  • Fick's Second Law
  • Stefan-Boltzmann Law
  • Planck's Law only
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The Correct Option is C

Solution and Explanation

Step 1: Understanding the Problem:
The question asks for the fundamental physical law of radiation heat transfer that relates the total emissive power of a blackbody to its absolute temperature raised to the fourth power.

Step 2: Key Formula or Approach:

The Stefan-Boltzmann law describes the total thermal energy radiated by a blackbody per unit surface area per unit time.
The mathematical relationship is given as:
\[ E = \sigma T^4 \]
where $E$ represents the total emissive power ($\text{W/m}^2$), $T$ represents the absolute temperature ($\text{K}$), and $\sigma$ represents the Stefan-Boltzmann constant ($\sigma \approx 5.67 \times 10^{-8} \text{ W/m}^2\text{K}^4$).

Step 3: Detailed Explanation:


Stefan-Boltzmann Law: Explains that the total radiative energy emitted by a blackbody is proportional to the fourth power of its absolute temperature ($T^4$).

Newton's Law of Cooling: Governs convective heat transfer, stating that the rate of heat loss from a body is proportional to the temperature difference between the body and its environment ($\Delta T$).

Fick's Second Law: Governs non-steady-state mass diffusion, predicting how concentration fields change over time.

Planck's Law: Describes the spectral distribution of electromagnetic radiation emitted by a blackbody in thermal equilibrium, rather than the integrated total emissive power.

Step 4: Final Answer:

Therefore, the Stefan-Boltzmann Law is the correct law relating emissive power to the fourth power of temperature.
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