If $\phi$ is the work function of photosensitive material in eV and light of wavelength of numerical

Question

If $\phi$ is the work function of photosensitive material in eV and light of wavelength of numerical value $\lambda=\frac{h c}{e}$ 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)

Professor PC Thomas Classes · Answer

(c) : According to Einstein photoelectric equation, Photon energy = K.E. + Work function Here, photon energy $=e \mathrm{eV}$ Work function $=\phi \mathrm{eV}$ \ $ 	herefore \quad e=	ext { K.E. }+\phi \quad \Rightarrow \quad 	ext { K.E. }=e-\phi $