Question

question 5
if a star is the same temperature as the sun but is a million times more luminous than the sun, then
that star is a lot less massive than the sun.
that star is a white dwarf star.
that star is bluer than the sun.
that star has a much bigger radius than the suns.

Explanation:

The luminosity ($L$) of a star is related to its radius ($R$) and temperature ($T$) by the Stefan - Boltzmann law $L = 4\pi R^{2}\sigma T^{4}$, where $\sigma$ is the Stefan - Boltzmann constant. If two stars have the same temperature ($T$) and one is more luminous, from the formula, the more luminous star must have a larger radius since $L\propto R^{2}$ when $T$ is constant. A star with the same temperature as the Sun is not bluer. A white - dwarf is typically faint and not extremely luminous. And a more luminous star (at the same $T$) is not less massive.

Answer:

that star has a much bigger radius than the Sun's.