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On weeks 2-4 homework, question 7 asks to calculate the max wavelength of radiation that will eject e- from a metal that has a work function of 4.78*10^-19 J. I used E=hc/wavelength, isolating wavelength = (6.626*10^-34 J/s)(3.00*10^8 m/s) / (4.78*10^-19). I got 4.16 * 10^-7 m, which we are asked to convert to angstroms. I got 4.16 * 10^-17 angstroms, but its still saying my answer is incorrect. Could someone help me out with whatever I'm doing wrong?
It might be helpful to write out the dimensional analysis for the conversion. (4.16x10-7m)(1 angstrom/10-10m). Also remember to double check that the answer makes logical sense. If you convert from meters to angstroms, you would expect to get more angstroms than meters, since they are much smaller.
I'm pretty good at making small mistakes in unit conversions; I find it helps if I just set up the conversion with a dimensional analysis-type setup so the units cancel and I plug into the calculator so I don't make an error with moving the decimal space. Sounds lowkey convoluted or lazy of me but that's how I'm able to avoid those types of errors!
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