The individual lines in a bright line emission spectrum represent specific wavelengths of light emitted by atoms or molecules when they transition from a higher energy state to a lower energy state. Each line corresponds to a particular electron transition within an atom.
When an atom absorbs energy, its electrons can jump to higher energy levels. When these electrons fall back to their original or lower energy levels, they release energy in the form of light. This emitted light is what we see as distinct lines in the emission spectrum.
The position of each line on the spectrum indicates the wavelength (or frequency) of the emitted light, which is unique to each element. For example, hydrogen has a specific set of lines, known as the Balmer series, which are characteristic of its atomic structure. By analyzing these lines, scientists can identify the element present and even determine its concentration in a sample.