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A graph shows the spectral distribution of radiant energy emitted by a black body at temperature T. Which of the following statements is/are correct?

1. The radiant energy is not distributed equally over all wavelengths.
2. There is a particular wavelength at which the spectral intensity is maximum.
3. The area under the curve equals the total rate at which the body radiates heat at that temperature.
4. All of the above statements are correct.

Correct answer: All of the above statements are correct.

Solution

The black-body curve is unequal across wavelengths, has a single peak (Wien), and its area equals the total radiated power (Stefan-Boltzmann), so all statements are correct.

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