A photoelectric surface is illuminated successively by monochromatic light of wavelength $$\lambda $$ and $$\lambda/2 $$. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material is
(h = Planck's constant, C = speed of light)

Which of the following figures represent the variation of particle momentum and the associated de-Broglie wavelength?

A certain metallic surface is illuminated with monochromatic light of wavelength, $$\lambda .$$ The stopping potential for photo-electric current for this light is 3V₀. If the same surface is illuminated with light of wavelength 2 $$\lambda $$, the stopping potential is V₀. The threshold wavelength for this surface for photo-electric effect is

When the energy of the incident radiation is increased nby 20%, the kinetic energy of the photoelectrons emitted from a metal surface increased from 0.5 eV to 0.8 eV. The work function of the metal is