# (Quantum Mechanics)

Please Help! (Quantum Mechanics)

I posted this in the Quantum Physics forum as well, but I ran across this one and thought it may help to put it here too. Sorry for the double post.

Hi everyone... I am new to this site. I am currently taking a major-related Chemistry course that is concentrating on quantum mechanics right now. I have been working on a homework question for about an hour now, and I am no closer to figuring it out than when I started. Something tells me that it's probably a pretty easy question, if I just knew where to begin. I need to calculate the longest wavelength (minimum frequency, right?) of light in nm that can be used to eject electrons from a surface, given that it takes 254kJ/mole. Can someone please help me!

## Answers and Replies

Related Introductory Physics Homework Help News on Phys.org
Light comes in packets. How much energy that packet has depends on the frequency. You need to find the energy it takes to eject a single electron (remember the size of a mole?) and find the frequency of light that has that amount of energy per packet (or quantum).

Thank you, thank you, thank you, thank you, thank you! You are a life saver! I was trying to make things way too difficult!

You can get a better understanding of Quantum Mechanics basics through OCW courses. Check out the following ocw courses from MIT and TUFTS.
http://www.opencontentonline.com/search.php?query_text=quantum+mechanics [Broken]

Cheers
Trilateral

Last edited by a moderator: