3. How is the atomic emission spectrum of an element related to these flame tests?

Atomic emission spectra are created when atoms of an element have energy added to them (by heating, or running electric current through an emission tube filled with a gas). With the naked eye, you see a single color of light (which is the sum total of all the colors of light produced by a given element).

Atomic emission spectrum is related to flame tests because flame produces light that has an emission spectrum.

Explanation:

An emission spectrum is the lines of colour in the spectroscope that are produced by the excited electrons that are part of Bohr's model. The flame's heat is absorbed into the electrons and makes them excited.