Question

A given photosensitive surface is being irradiated by a monochromatic radiation of wavelength λ. The stopping potential, needed in this set up, is V_S. 

The deBroglie wavelength, associated with a beam of electrons, accelerated through a potential V, equals the threshold wavelength for the above given photosensitive surface. The relation, between V_S and V, is then

Answer 1

Correct option :  (4)

Explanation :

Let W be the work function for the given photosensitive surface. We then have hc/λ = eVs + W

If λ₀ be the threshold wavelength, for the given photosensitive surface, we have 

Also, the deBroglie wavelength, λ_B, associated with the electron beam, is given by