If p is the momentum of the fastest electron ejected from a metal surface after the irradiation of light having wavelength λ, then for 1.5 p momentum of the photoelectron, the wavelength of the light should be:(Assume kinetic energy of ejected photoelectron to be very high in comparison to work function)
12λ
23λ
49λ
34λ
Solution:
Correct option is D. 49λ Solution:- (D) 49λ hv − φ = KE ⇒ (hc/λ)incident = KE + φ (hc/λ)incident ≈ KE KE = p²/2m = hc/λ..(1) ⇒(1.5p)²/2m = hc/λ'.. (2) Divide (1) and (2) (1.5)² = λ/λ' ⇒λ' = 4λ/9