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Alissa Stanley 3G
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Postby Alissa Stanley 3G » Wed Oct 11, 2017 11:55 am

Question 1.13 asks you to use the Rydberg formula for atomic hydrogen to calculate the wavelength of radiation generated by the transition from n=4 to n=2. I got the equation 2.988x10^8 = 3.29x10^15((1/16) - (1/4)) x wavelength. Therefore, I thought n1=16 and n2=4, but the answer is flipped. If the equation asks for the transition from 4 to 2, then why wouldn't 4 by n1 and 2 be n2?

Priyanka Bhakta 1L
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Re: 1.13

Postby Priyanka Bhakta 1L » Wed Oct 11, 2017 12:05 pm

I believe that 4 is n2 and 2 is n1 because the formula is looking at the energy levels n1 and n2 in reference to the actual formation of the electron levels. So, n1 is always the lower energy level and n2 is greater. Think about the sketch that Dr. Lavelle drew on the board in lecture, as well as in the modules, where the electron energy levels are written from lowest to highest. So even though the problem is asking about going down energy levels, the levels are still labeled from lowest to highest. Thus, when substituting numbers into the formula, n1 is always the lower level and n2 is the higher level. I hope this helps to clarify why n1 is 2 and n2 is 4.

Ryan Sydney Beyer 2B
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Re: 1.13

Postby Ryan Sydney Beyer 2B » Wed Oct 11, 2017 12:40 pm

You can also think of the equation to be .

This might make things a little bit clearer because the change in energy levels is going from 4, which is the initial state, and ending at 2, which is the finial state, because the problem says that radiation is being generated and leaving the system so you know that the electron must be relaxing at a lower energy level than it begins at. Hope this is able to clear up some of the confusion!

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