Opacity is
A)the balance between the pressure and force of gravity inside a star.
B)the force that binds protons and neutrons together to form a nucleus.
C)the force that binds an electron to the nucleus in an atom.
D)a measure of the resistance to the flow of radiation (photons) through a gas.
E)the temperature and density at which a gas will undergo thermonuclear fusion.

Question

Quizplus · Accepted Answer

Opacity is a measure of the resistance to the flow of radiation (photons) through a gas. It depends on factors such as the density, temperature, and composition of the gas, and determines how easily radiation can transfer heat within the gas or out of it. In astronomy, opacity is an important parameter for understanding the behavior of radiation in stars, planetary atmospheres, and interstellar matter.

Opacity Is