When a metallic surface is illuminated with radiation of wavelength ' ', the stopping potential is ' V '. If the same surface is illuminated with radiation of wavelength ' 2 ', the stopping potential is ' ( v 4 ) ,. The threshold wavelength for the metallic surface is

Step-by-step solution

For stopping potential V , eV = hc - hc ₀ For stopping potential V 4 , eV 4 = hc 2 - hc ₀ Taking the ratio, we get aligned & 4= ( 1 - 1 ₀ ) 1 2 - 1 ₀ & 4 ( 1 2 - 1 ₀ )= 1 - 1 ₀ & ( 2 - 4 ₀ )= 1 - 1 ₀ & ( 2 - 1 )= 1 ₀ + 4 ₀ & ( 1 )= 3 ₀ & ₀=3 aligned