Why are the thickness (or brightness) of spectral lines different?

Question

Something to do with the number of photons?

6400 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-11-28T07:51:43

Actually I got the answer:

The thickness (brightness) depends on the number of photons. When there is more frequency, there is more energy so it emits more photons.