Passage IV

A blackbody is an object that absorbs all of the radiation that strikes it. The blackbody also emits radiation at all wavelengths; the emitted radiation is called blackbody radiation. The brightness of blackbody radiation at a given wavelength depends on the temperature of the blackbody. A graph of brightness versus wavelength for a blackbody is called a blackbody curve. Blackbody curves for the same blackbody at 3 different temperatures are shown in the figure below.

21. Based on the figure, the maximum of the blackbody curve will equal 75 × 106 watts per m3 when the temperature of the blackbody is closest to:

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

Judging from the figure, the maximum corresponding to 500 K is about 130×10-6, and the maximum corresponding to 400 K is about 40×10-6. The 75×10-6 given in the question stem is just within this range, indicating that the temperature of the blackbody should also be between 400 K-500 K, and option C is in line