# Calculate the energy and wavelength of the photon

#### shezill

this was a question in a prevoius year exam that im really stuck on.

An atom has an energy level 1.8 eV above ground state. When excited, it returns to the ground state and emits a photon. Ccalculate the energy and wavelength of the photon.

thank you

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#### FZ+

Doesn't seem very difficult...

Energy of photon = energy lost by electron as it goes down the energy level.

Also, E = hf = h*c/l

Plug in the numbers...

And don't forget that 1 eV = 1.6 * 10^-19 J

Last edited:

#### shezill

but what numbers do i plug in. Do i have to use a fomula on the 1.8eV first to get the numbers or just use that.

#### frankR

Originally posted by shezill
but what numbers do i plug in. Do i have to use a fomula on the 1.8eV first to get the numbers or just use that.
1 eV = 1.6x10^-19 Joules

Convert it to Jays.

#### shezill

thank you very much

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