## College Physics (4th Edition)

$\lambda = 478~nm$
We can find the threshold wavelength: $E = \frac{hc}{\lambda}$ $\lambda = \frac{hc}{E}$ $\lambda = \frac{(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{(2.60~eV)(1.6\times 10^{-19}~J/eV)}$ $\lambda = 4.78\times 10^{-7}~m$ $\lambda = 478~nm$