Physics 2011 JAMB Past Questions - Question 17: A perfect emitter or absorber of radiant energy is a

Correct Answer

D

Explanation

A perfect emitter or absorber of radiant energy is referred to as a "blackbody." A blackbody is an idealized physical body that absorbs all incident electromagnetic radiation (such as light, heat, and other forms of radiant energy) and emits radiation at all frequencies and wavelengths. It is considered a perfect emitter and absorber because it does not reflect any radiation; instead, it absorbs all energy that falls on it and re-emits it according to Planck's law of blackbody radiation.

The behavior of blackbodies is described by Planck's radiation law, which is a fundamental equation in quantum mechanics and thermodynamics. This law characterizes the spectral distribution of radiation emitted by a blackbody as a function of its temperature. The spectrum of a blackbody's radiation is continuous, and the distribution of emitted energy depends on temperature, with higher temperatures resulting in more intense and shorter-wavelength radiation.

Real-world objects are not perfect blackbodies, but they can be close approximations under certain conditions. For example, objects like a piece of metal at a high temperature can behave as nearly perfect emitters and absorbers in certain spectral regions. Understanding the behavior of blackbodies is essential in fields such as thermodynamics, astrophysics, and materials science.