1) The light of wavelength λ incident on the surface of metal having work function ϕ emits the electrons. The maximum velocity of electrons emitted is [c= velocity of light, h= planck's constant, m= mass of electron] A) [2(hv−ϕ)λmc] B) [2(hc−λϕ)mλ]1/2 C) [2(hc−λ)mλ]1/2 D) [2(hc−ϕ)mλ] Answer: Option BExplanation: In photoelectric edffect, the maximum kinetic energy possessed by the particle. KEmax=hv−ϕ 12mv2=hcλ−ϕ [∵v=cλ] ⇒ v2=2(hc−ϕλ)λm v=[2(hc−ϕλ)λm]1/2