MHT CET202615 April 2026Evening ShiftPhysicsDual Nature of MatterActual
When a metallic surface is illuminated with a radiation of wavelength ' ', the stopping potential is 'V'. If the same surface is illuminated with radiation of wavelength 6 , the stopping potential is ( V 12 ) . The threshold wavelength for the surface is
Options
- A5
- B10
- C11
- D12
Correct answer
C. 11
Step-by-step solution
Using Einstein's photoelectric equation, eV = hc - hc ₀ For the first case: eV = hc - hc ₀ For the second case: eV 12 = hc 6 - hc ₀ Multiplying the second equation by 12 gives: eV = 2hc - 12hc ₀ Equating the two expressions for eV : hc - hc ₀ = 2hc - 12hc ₀ 11hc ₀ = hc ₀ = 11 Answer: 11