When a piece of metal is illuminated by a monochromatic light of wavelength , then stopping potential is 3 ~V - s . When same surface is illuminated by light of wavelength 2 , then stopping potential becomes V_ s . The value of threshold wavelength for photoelectric emission will be

Step-by-step solution

According to first situation wavelength of incident radiation, ₁= Stopping potential, V₀₁=3 V_ s According to Einstein's photoelectric equation, array ll & K_ =h v₁- & e V₀₁= h c ₁ - h c ₀ & [ where, ₀= . threshold wavelength.] & e 3 V_ s =h c ( 1 - 1 ₀ ) & 3 V_ s e=h c ( 1 - 1 ₀ ) array According to second situation, wavelength of incident radiation, ₂=2 Stopping potential, V₀₂=V_ S Again, Einstein's photelectric equation, gathered K_ =h v ₂- e V₀₂=h c ( 1 ₂ - 1 ₀ ) e V_ s =h c ( 1 2 - 1 ₀ ) gathered Dividing Eq.