State and explain Stefan's law of radiation.

Explanation

### Step-by-Step Text Solution

**Step 1: Understanding the Concept of Radiation**
Radiation is the process by which energy is emitted as particles or waves. In the context of thermal radiation, all objects emit radiation depending on their temperature.

**Step 2: Definition of Stefan's Law**
Stefan's Law of Radiation states that the amount of thermal radiation emitted per unit time from a black body is directly proportional to the fourth power of its absolute temperature. Mathematically, this can be expressed as:
\[ P \propto A T^4 \]
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