Which of the following statements about thermal radiation is always true?
A)A hot object emits more X-rays than a cool object.
B)A hot object emits more radio waves than a cool object.
C)A hot object emits more total radiation than a cool object.
D)A hot object emits more total radiation per unit surface area than a cool object.
E)A hot object emits less total radiation than a cool object.

Question

Quizplus · Accepted Answer

This statement is known as the Stefan-Boltzmann law and states that the total amount of thermal radiation emitted by an object is proportional to the fourth power of its temperature (in Kelvin), and is proportional to its surface area. Therefore, a hot object emits more total radiation per unit surface area than a cool object. Choices A and B are not necessarily true, as the type of radiation emitted by an object depends on its temperature and atomic composition. Choice C and E are contradictory, and the total amount of radiation emitted by an object depends on its temperature and surface area.

Which of the Following Statements About Thermal Radiation Is Always