Achieve 2 #12

[Megan Cai 1H]

The question states "The electron affinity of thulium has been measured by a technique known as laser photodetachment electron spectroscopy. In this technique, a gaseous beam of the anions of an element is bombarded with photons from a laser. Electrons from the anion are then ejected and their energies are detected. The incident radiation had a wavelength of 1064 nm, and the ejected electrons were found to have an energy of 0.137 eV. The electron affinity is the difference in energy between the incident photons and the energy of the ejected electrons. Determine the electron affinity of thulium in units of electron volts per atom."

I've gotten it wrong many times and I am following the instructions on the feedback but I am still getting it wrong. I converted the wavelength into meters, put it into E=hc/lamda and converted my answer to eV by dividing the energy(J) by 1.602*10-19. I then subtracted 0.137 eV from this value and then that should be my electron affinity but my answer is wrong. Can anyone help?

[Michael Crannell 1H]

I am not sure where you went wrong, everything you did so far looks correct. I know I got 1.165eV initially then had to subtract the .137 to find my answer. Unit conversions tricked me up a few times but if you remember to do E=hc/lambda then divide again by the number you gave I think you should get it.

[Eszter Kovacs 1A]

Hi!

I also got 1.165 eV as the energy of the incident light, which gave my the right result for the electron affinity. Maybe your wavelength wasn't converted to meters right.

[Brianna Mercado 3D]

Hi! For part B its just unit conversion!(:

[14b_student 2E]

Make sure you convert your wavelength to meters and use 1eV=1.602x10^-19. I kept getting this wrong for not using parentheses in my calculator so be careful of that as well!