Which of the following characteristics is true of black bodies?

Black bodies are idealized physical objects that perfectly absorb all incident radiation, meaning they do not reflect any light or radiation that strikes them. This characteristic leads to black bodies being perfect absorbers and emitters of thermal radiation. According to Planck's law and the Stefan-Boltzmann law, a black body will emit radiation across a spectrum of wavelengths when heated, and its emission is dependent on its temperature.

While it is true that black bodies can emit radiation at varying temperatures, the defining characteristic that distinguishes them fundamentally is their ability to absorb all incident radiation without reflecting any. This feature makes them ideal for studying thermal radiation and sets the foundation for understanding various physical phenomena related to heat and light.