Question
The ground state of a certain type of atom has energy of $-E_o$. What is the wavelength of a photon with enough energy to ionize the atom when it is in the ground state, so that the ejected electron has kinetic energy equal to $2E_o$?
1. $\lambda = \dfrac{hc}{3E_o}$
2. $\lambda = \dfrac{hc}{2E_o}$
3. $\lambda = \dfrac{hc}{E_o}$
4. $\lambda = \dfrac{2hc}{E_o}$