How is atomic emission spectrum related to 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 gas). With the naked eye, we see a single colour of the light (which is the sum total of all the colours of light produced by a given element). A tool called a spectroscope will reveal the unique frequencies of light being given off by the atoms of the element.