A typical white dwarf has a surface temperature about 4 times that of the Sun and a radius about 1 percent that of the Sun. What can one determine about the luminosity of a typical white dwarf from this information?
A) The white dwarf will be less luminous than the Sun.
B) The white dwarf and the Sun will have about the same luminosity.
C) The white dwarf will be more luminous than the Sun.
D) Nothing can be concluded about the relative luminosities from this information.

Question

Quizplus · Accepted Answer

The luminosity of a star can be estimated using the Stefan-Boltzmann law, which states that luminosity is proportional to the fourth power of the temperature and the square of the radius. Given that the white dwarf's temperature is 4 times that of the Sun and its radius is 1% of the Sun's, its luminosity would be significantly lower than the Sun's, despite its higher temperature, due to its much smaller size.

A Typical White Dwarf Has a Surface Temperature About 4