The following graph represents the radiant power versus wavelength of the black body. The area under the curve represents (a) the maximum wavelength emitted by the object. (b) the minimum wavelength emitted by the object. (c) the total energy emitted per unit time by the black body at some particular wavelength (d) the total energy emitted per unit time per unit area by the black body at all wavelengths.

Answer: (d). The y-axis is energy emitted per unit time per unit area per unit wavelength, Eλ. Area under the curve = ∫ Eλ dλ adds this over all wavelengths. This is the total energy emitted per unit time per unit area, E = σ T⁴. So the answer is (d).

The following graph represents the radiant power versus wavelength of… | MHT CET 2025 (20 Apr, Shift 2)

Q45MHT CET 2025 · 20 APR · SHIFT 2Easy

Thermal Radiation: Black Body, Stefan & Wien

The following graph represents the radiant power versus wavelength of the black body. The area under the curve represents

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Answer: (d)

The y-axis is energy emitted per unit time per unit area per unit wavelength, $E_\lambda$ .
Area under the curve $= \int E_\lambda\, d\lambda$ adds this over all wavelengths.
This is the total energy emitted per unit time per unit area, $E = \sigma T^4$ .
So the answer is (d).

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