The Stefan-Boltzmann law relating energy per unit area F emitted by an object to its temperature T, F = σT ⁴, is obeyed ideally by what type of object? A)only hot gases, whose atoms emit and absorb only specific colors (e.g., neon tubes) B)all objects, whatever their color or reflective properties C)a red-colored object that absorbs blue light but reflects red light D)a blackbody, a perfect absorber and emitter of energy at all wavelengths

Question

Quizplus · Accepted Answer

The Stefan-Boltzmann law is obeyed ideally by a blackbody, which is a theoretical object that absorbs all radiation incident upon it and has a perfectly uniform temperature throughout its volume. A blackbody is a perfect absorber and emitter of energy at all wavelengths, and can be used as a reference object to compare the radiation emitted by other objects. Choice A is incorrect because the Stefan-Boltzmann law applies to all objects, not just hot gases that emit specific colors. Choice B is incorrect because the radiation emitted by an object depends on its temperature and emissivity (ability to emit radiation), not just its color or reflective properties. Choice C is also incorrect because the color and reflective properties of an object do not determine whether or not it obeys the Stefan-Boltzmann law.

The Stefan-Boltzmann Law Relating Energy Per Unit Area F Emitted