Photoelectric effect for three metals

Light of $254\ \text{nm}$ from a mercury lamp falls on sodium, zinc and copper, with work functions of $2.3\ \text{eV}$, $4.3\ \text{eV}$ and $4.7\ \text{eV}$. You will make the program find the largest kinetic energy of the electrons from each metal, the threshold wavelength of zinc, and how many of the three metals give electrons in light of $365\ \text{nm}$. Then it draws the stopping potential against frequency for each metal.

The idea. $KE_{\max} = \dfrac{hc}{\lambda} - \phi$, with $hc = 1240\ \text{eV nm}$, and $\lambda_0 = \dfrac{hc}{\phi}$.

Your tasks.

1. Inside the loop, work out ke, the largest kinetic energy in eV for the metal with work function phi.
2. Find lam0_zinc, the threshold wavelength of zinc in nm.
3. Find count, how many of the three metals give electrons at $365\ \text{nm}$.