Which atom or ion produces the strongest absorption lines in the spectra of stars with the highest surface temperatures?
A) He II, ionized helium
B) Fe I, neutral iron
C) Ca II, singly ionized calcium
D) H I, neutral hydrogen

Question

Quizplus · Accepted Answer

As the surface temperature of a star increases, more and more ionization of atoms occurs. He II, ionized helium, has the strongest absorption lines of all the choices given in the question and is produced in stars with high surface temperatures.

Which Atom or Ion Produces the Strongest Absorption Lines in the Spectra