Example 4: Light of wavelength 400 nm falls on a metal surface having a work function 1.70 eV. What is the maximum kinetic energy of the photoelectrons emitted from the metal? ($c = 3.00 \times 10^8 \text{ m/s}$, $h = 6.626 \times 10^{-34} \text{ J} \cdot \text{s} = 4.141 \times 10^{-15} \text{ eVs}$, $1 \text{ eV} = 1.60 \times 10^{-19} \text{ J}$)