E=hv and ΔE=hv

[JennyCKim1J]

Under Atomic Spectra, I wrote down "E = hv, ΔE = hv". What is the difference between the two equations? Is E equal to ΔE? When are these equations used?

[ConnorThomas2E]

ΔE is the change in energy and can have either a positive or negative value. You usually use the equation when an electron absorbs energy to move to a different energy level.
E is the energy of a given wavelength. It typically shows you how much energy a photon has.

[Julie Steklof 1A]

ΔE is the energy change that occurs when an atom absorbs or emits a photon (atomic spectra experiment) whereas E is used to calculate the energy per photon when completely removing electrons from an atom (photoelectric effect).

[Wenxin Fan 1J]

In chemistry the delta sign usually symbolizes change (in chemical equations it can show the application of heat). Therefore ΔE=hv is the equation for the change in energy while E=hv is just an energy calculation.
-Wenxin Fan 1H