Solution:

The statement "Good absorbers of heat are good emitters" is explained by Kirchhoff's Law of Thermal Radiation.

Explanation:

Kirchhoff's law states that, for a body in thermal equilibrium, the ability to absorb radiation (absorptivity) is equal to its ability to emit radiation (emissivity) at the same temperature and wavelength. In simpler terms, materials that are good at absorbing heat also radiate or emit heat efficiently.

- Good absorbers: A material that can absorb a large amount of radiation from its surroundings is considered a good absorber. For example, objects with **dark, rough surfaces** absorb more heat than those with light, shiny surfaces.

- Good emitters: The same objects that absorb heat well also tend to emit heat efficiently when they are at a higher temperature than their surroundings. This is why a dark object, after absorbing heat, cools down faster by emitting more radiation compared to a shiny object.

For example:
- A black object absorbs more heat from sunlight (good absorber) and, when placed in the shade, radiates heat more quickly (good emitter).

Practical Example:

A black pot heats up quickly in the sun (good absorber) and cools down quickly at night (good emitter). Conversely, a shiny or reflective surface absorbs less heat and also emits less heat, meaning it retains heat longer.

This relationship between absorption and emission helps in designing materials for applications like thermal insulation, radiators, and solar panels.