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AP EAMCET · PHYSICS · Thermal Properties of Matter

The temperature of a spherical black body is inversely proportional to its radius. If its radius is doubled, then the power radiating from it will be

  1. A doubled
  2. B \(\frac{1}{4}\) times of initial value
  3. C halved
  4. D four times of initial value
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{1}{4}\) times of initial value

Step-by-step Solution

Detailed explanation

From Eqs. (i), (ii) and (iii), we have, \( P=\sigma 4 \pi R^2 \cdot\left(\frac{k^4}{R^4}\right) \text { or } P \propto \frac{1}{R^2} \) So, when radius is doubled, radiating power of sphere becomes one fourth.