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Homework 13 Question 8

0 votes
2,761 views

An electron is in the ground state of an infinite square well. The energy of the ground state is E1 = 1.14 eV.

(a) What wavelength of electromagnetic radiation would be needed to excite the electron to the n = 2 state?

(b) What is the width of the square well?

 

I am so confused by this question. I have been using the equation E = (n^2 h^2)/ (8mL^2) and solving the equation for L. Am I using n=1 or n=2? Is the value I get for L my final answer or do I need to plug it into another equation?

 

asked Dec 2, 2014 in Intro College Physics by anonymous

1 Answer

0 votes
The equation is correct. For n=1, it is the ground state, which is ||E_1=\frac {h^2}{8mL^2}||. For n>1 states, the energy can be written as ||E_n=n^2E_1||. This will allow you to find the difference between states easily.

(b)To find L, one can use any value of n. For simplicity, ||E_1|| can be used to find L.
answered Dec 4, 2014 by PhysicsDude (21,750 points)
Can you elaborate on this, please? My figures were E1=0.62eV and n=5. I used the formula above, but wasn't able to get the correct answer per webassign.
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