If a certain star shows a strong absorption spectrum in hydrogen Balmer lines, the surface temperature of the star is hot enough that
A) virtually all of the hydrogen atoms are ionized.
B) many hydrogen atoms have electrons in the n = 2 energy level.
C) many hydrogen atoms have electrons in the n = 3 energy level.
D) many helium atoms have been converted to hydrogen atoms.

Question

Quizplus · Accepted Answer

The Balmer series of hydrogen is most prominent when many hydrogen atoms have electrons in the n = 2 energy level, as this series involves transitions from higher energy levels to n = 2. This indicates that the surface temperature of the star is such that it excites hydrogen atoms to this state without fully ionizing them.

If a Certain Star Shows a Strong Absorption Spectrum in Hydrogen