If \(\phi\) is the work function of photosensitive material in eV and light of wavelength of numerical value \(\lambda = \frac{hc}{e}\) metre, is incident on it with energy above its threshold value at an instant then the maximum kinetic energy of the photo-electron ejected by it at that instant (Take \(h\)-Planck’s constant, \(c\)-velocity of light in free space) is (in SI units):