## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

$\lambda = 497~nm$
We can write an expression for the energy of each photon: $E = \frac{h~c}{\lambda}$ We can write an expression for the photon emission rate: $R = \frac{P}{E}$ $R = \frac{P~\lambda}{h~c}$ We can find the required wavelength of light: $R = \frac{P~\lambda}{h~c}$ $\lambda = \frac{R~h~c}{P}$ $\lambda = \frac{(2.50\times 10^{17})(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{0.100~W}$ $\lambda = 4.97\times 10^{-7}~m$ $\lambda = 497~nm$