Work function of a metal X equals ionisation energy of $\text{Li}^{2+}$ ion in second excited state. Work function of another metal Y equals ionisation energy of $\text{He}^+$ ion with electron in $n = 4$. Now a photon of energy $x$ falls on both the metals such that maximum kinetic energy of photoelectron emitted from metal Y is half that of photoelectron emitted from metal X. Choose the correct statement(s). ($E$ = magnitude of potential energy of electron in ground state of hydrogen atom)