A photon of energy ‘2’ ev is incident on a metal, The minimum de-Broglie wave length of the emitted electrons is λ. When the wave length of the incident radiation is reduced by 60% the minimum de-Broglie wave length of the emitted electrons is λ2 The work function of the metal is

if de Broglie wavelength becomes halved momentum becomes doubled and kinetic energy becomes 4 times  and if incident wavelength decreases by 60%  it means it becomes 40%  λ becomes 410λ  frequency becomes 104ν Eienstein equation hν =w+k----1            second time h 104ν = w+4k----2 solving w=0.5 hν  here hν= 2ev