Which of the following best describes why a white dwarf cannot have a mass greater than the 1.4-solar-mass limit?
A)Electron degeneracy pressure depends on the speeds of electrons,which approach the speed of light as a white dwarf's mass approaches the 1.4-solar-mass limit.
B)White dwarfs get hotter with increasing mass,and above the 1.4-solar-mass limit they would be so hot that even their electrons would melt.
C)White dwarfs are made only from stars that have masses less than the 1.4-solar-mass limit.
D)The upper limit to a white dwarf's mass is something we have learned from observations,but no one knows why this limit exists.

Question

Quizplus · Accepted Answer

Electron degeneracy pressure, which supports a white dwarf against gravity, depends on the speeds of electrons. As a white dwarf's mass approaches the 1.4-solar-mass limit, the electrons approach relativistic speeds, which reduces their effectiveness in supporting the star against gravity. Therefore, a white dwarf cannot have a mass greater than 1.4 solar masses.

Which of the Following Best Describes Why a White Dwarf