College Chem.
posted by B .
Determine the longest wavelength of light required to remove an electron from a sample of potassium metal, if the binding energy for an electron in K is 1.76 × 103 kJ/mol.

isn't Planck's equation working?
Energy= plancksconstant*speedlight/wavelength
You will have to get energy per electron, or
energy= 1.76E3*1E3avagradros number to get energy in joules/electron 
opps, division sign disappeared.
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energy= 1.76E3*1E3/ avagradros number to get energy in joules/electron