If the photons of frequency v are incident on the surfaces of metal A and B of threshold frequencies v/2 and v/3 respectively, then what will be the ratio of the maximum kinetic energy of electrons emitted from A to that of B ?

2:3 3:4 1:3 9:4

3:4

hv=hv/2 + Ka ⇒ Ka=hv/2 hv=hv/3 + Kb ⇒ Kb=2hv/3 divide the two equations to get 3:4.