What determines the specific color of the light photon emitted when an electron drops energy levels?

Answer

The size of the energy gap the electron jumped across.

The specific color of the light photon is determined by the size of the energy gap the electron jumps across during its transition to a lower energy level.

What determines the specific color of the light photon emitted when an electron drops energy levels?

#Videos

Why Are Emission Nebulae Different Colors? - Physics Frontier

What Makes Emission Nebulae Glow In Distinct Colors? - YouTube

lightcolornebulagasemission