Emission Gap Subtracts Lower from Upper - Atomic Spectra: Energy Levels and Line Series Step by Step

An emission gap is upper energy minus lower energy. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

An emission line cites two levels

The upper energy is 9 joules and the lower energy is 4 joules.

E_{upper}=9\ \mathrm{J},\quad E_{lower}=4\ \mathrm{J}

The gap is upper minus lower

The checked emission gap is 5 joules.

\Delta E=9 - 4=5\ \mathrm{J}