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beastman

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## Homework Statement

An electron is in a one-dimensional rectangular potential well

with barriers of inﬁnite height. The width of the well is equal to L = 5 nm.

Find the wavelengths of photons emitted during electronic transitions from the

excited states with quantum numbers n = 2, λ21, and n = 3, λ31, to the ground

state with n = 1. (Answer: λ21 ≈ 1.15 µm and λ31 ≈ 0.43 µm.)

## Homework Equations

E1 = (∏^2)*h^2/2meL^2 = 0.3737/L^2 eV

ΔE = En+1 − En = (2n + 1)E1

ε = hf

## The Attempt at a Solution

I found the ground state energy to be 0.0149 eV. Then using the ΔE equation for n=2,3 I found the energies of the emitted photons to be 0.0745 eV and 0.1043 eV, respectively.

Using these energies in Plancks formula is getting me the wrong wavelengths, what am I doing wrong?

Please help!

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