MHT CET202618 April 2026Evening ShiftPhysicsDual Nature of MatterActual
The maximum kinetic energies of photoelectrons emitted are K₁ and K₂ when light of wavelength ₁ and ₂ respectively are incident on a metallic surface. If ₁ = 3 ₂ then
Options
- AK₁ = K₂ 3
- BK₁ < K₂ 3
- CK₁ = 3K₂
- DK₁ = 2 3 K₂
Correct answer
B. K₁ < K₂ 3
Step-by-step solution
According to Einstein's photoelectric equation, the maximum kinetic energy of emitted photoelectrons is given by K = hc - , where is the work function of the metal. For wavelength ₁ : K₁ = hc ₁ - For wavelength ₂ : K₂ = hc ₂ - Given ₁ = 3 ₂ , substituting this in the first equation gives: K₁ = hc 3 ₂ - Multiplying the equation by 3 yields: 3K₁ = hc ₂ - 3 From the second equation, substituting hc ₂ = K₂ + into the above relation: 3K₁ = (K₂ + ) - 3 3K₁ = K₂ - 2 Since the work function > 0 , it follows that: 3K₁ K₁ An