Question

An absorption spectrum of oxygen is shown below.

A rainbow for a line spectra from purple through red. There are 5 black lines in purple, 6 black lines in blue, 3 black lines in blue-green, 3 black lines in the green, 6 black lines in the orange and 5 black lines in red.

What is most likely the emission spectrum of oxygen?

A rainbow for a line spectra. There are 4 lines in purple, 4 lines in blue, 3 lines in blue-green, 6 lines in the yellow, 4 lines in the orange and 15 lines in red.
A rainbow for a line spectra. There are 4 lines in purple, 4 lines in blue, 3 lines in blue-green, 7 lines in the green, 6 lines in the yellow, 5 lines in the orange and 10 lines in red.
A rainbow for a line spectra. There are 4 lines in purple, 4 lines in blue, 2 lines in blue-green, 4 lines in the green, 2 lines in the yellow, 3 lines in the orange and 4 lines in red.
A rainbow for a line spectra. There are 5 lines in purple, 6 lines in blue, 1 line in blue-green, 4 lines in the green, 3 lines in the yellow, 4 lines in the orange and 4 lines in red.

Answer 1

An element's emission spectrum shows bright lines at the same wavelengths where its absorption spectrum shows dark lines. So the emission spectrum should have the same set of lines (same positions / same counts in each color band) as the absorption spectrum — i.e. bright lines replacing the dark ones.

Of the given choices the fourth option (5 purple, 6 blue, 1 blue‑green, 4 green, 3 yellow, 4 orange, 4 red) is the closest match, so choose that one.