The principle of a flame photometer is based on the emission of light by atoms when they are heated in a flame. The sample's atoms are excited to a higher energy level, and as they return to their ground state, they emit light at specific wavelengths. The intensity of this emitted light is measured and is proportional to the concentration of the element in the sample.

A Flame Photometer is a specialized instrument used in analytical chemistry to measure the concentration of certain metal ions in a solution. It operates based on the principle of emission spectroscopy, specifically flame emission spectroscopy.