Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: zerox0o on September 19, 2009, 03:43:47 PM

If it takes 3.92 × 10−19 J of energy to eject an electron from the surface of a certain metal, calculate the longest possible wavelength, in nanometers, of light that can ionize the metal.
How do I do this? I am really clueless... ???
thank you!!!

How do you calculate the energy of light of a particular wavelength? Hint Planck's constant is needed.

How do you calculate the energy of light of a particular wavelength? Hint Planck's constant is needed.
(energy) = (Planck constant)(frequency)  (work function)
(speed of wave) = (frequency)(wavelength)
E = hc/λ  φ
λ = hc/(E + φ)
k i got it! thanks :D