In an experiment on photo electric emission , following observations were made ; (1) Wavelength of incident light = $\;1.98\times10^{-7}m\;$ 2 Stopping potential = $\;2.5 volt\;$. Then kinetic energy of photoelectrons with maximum speed and Thus hold frequency are respectively

Question

$(a)\;5eV,9\times10^{14} Hz\qquad(b)\;2.5eV,9\times10^{14} Hz\qquad(c)\;5eV,18\times10^{14} Hz\qquad(d)\;2eV,18\times10^{14} Hz$