Light of frequency 8.41×1014Hz is incident on a metal surface. Electrons with a maximum speed of 7.5×105ms−1 are ejected from the surface. Calculate the threshold frequency for photo emission of electrons. Also find the work function of the metal in electron volt (eV). Given, Planck's constant h=6.625×10−34Js−1 and mass of the electron 9.1×10−31Kg.