Analytical Chemistry UF: Comparing Wavelengths & Frequencies

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The discussion revolves around a question from an Analytical Chemistry final regarding the frequency difference between two wavelengths of the sodium D1 line in vacuum and air. One participant believed the frequency difference was zero, while others calculated it as 1.409x10^11 Hz. The key point raised is whether the change in wavelength is due to the speed of light differing in vacuum versus air, and if the frequency remains constant. The participant confirmed their understanding that frequency should not change despite the differing wavelengths. The conclusion affirms that the participant achieved a high score on the final exam.
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Question 20 from our final I just took (Analytical Chemistry UF).

"You may recall that the wavelength of the sodium D1 line in vacuum is 589.7558nm. In air it becomes 589.5924nm. What is the difference in frequency for these two wavelengths."


I said 0. All the other people did the math for the two wavelengths and subtracted them and got 1.409x10^11 Hz.

The test was multiple choice so they were both potential responses.

Am I right in assuming that the difference in their wavelengths was due to the change in speed of light in a vacuum vs air? And that the frequency is supposed to be constant for both? Or is this not the same thing?

Thx!
 
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Zero is the correct answer.
 


Sweet that gives me a 95 on the final and I needed a 93 to get the A :biggrin:
 


(and thanks for the reply as well)
 
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