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When a body is heated to a higher temperature T', which of the following statements about its blackbody radiation curve are correct? (A) Intensity rises at every wavelength. (B) Peak intensity shifts to a shorter wavelength. (C) The area under the curve increases. (D) The area under the curve is proportional to the fourth power of the temperature.

1. (A), (B) and (C) only
2. (A) and (C) only
3. (B), (C) and (D) only
4. (A), (B), (C) and (D)

Correct answer: (A), (B), (C) and (D)

Solution

All four statements describe the standard properties of blackbody curves at higher temperature: greater intensity everywhere, peak shifting to shorter wavelength (Wien), increasing area, and area proportional to T⁴ (Stefan-Boltzmann).

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