With reference to the observations in photo-electric effect, identify the correct statements from below: (A) The square of maximum velocity of photoelectrons varies linearly with frequency of incident light. (B) The value of saturation current increases on moving the source of light away from the m…

Question

With reference to the observations in photo-electric effect, identify the correct statements from below: (A) The square of maximum velocity of photoelectrons varies linearly with frequency of incident light. (B) The value of saturation current increases on moving the source of light away from the metal surface. (C) The maximum kinetic energy of photo-electrons decreases on decreasing the power of LED source of light. (D) The immediate emission of photo-electrons out of metal surface cannot be explained by particle nature of light. (E) Existence of threshold wavelength cannot be explained by wave nature of light. Choose the correct answer from the options given below:

Accepted Answer

(2) (A) and (E) only. (A) 1/2 mvₘₐₓ²=h
u-φ, so vₘₐₓ² is linear in 
u. Correct. (B) Moving the source away reduces the intensity at the surface, so the saturation current falls. Incorrect. (C) Power changes the number of photons, not the energy of each, so Kₘₐₓ is unchanged. Incorrect. (D) Immediate emission follows naturally from one photon delivering its whole energy at once. Incorrect. (E) A wave of any wavelength should eventually supply enough energy, so a threshold needs the photon picture. Correct. Correct set: (A) and (E).

Step-by-step solution

Why the other options are wrong