For a photosensitive surface,threshold wave-length is `lambda_0`.Does photoemission occur,if the wavelength `(lambda)` off the incident radiation is
less than `lambda_0`?Justify you answer.

An electromagnetic wave of length lambda is incident on a photosensitive surface of negligible work function. If the photoelectrons emitted from the surface have the same de-Broglie wavelength lambda , prove that lambda=(2mc)/h lambda_1^2

The figure shows the stopping potential for the phototelectron versus (1/lambda) graph for two metals A and B, lambda being the wavelength of incident light If the distance between the light source and the surface of metal A is increased, how will the stopping potentail for the electrons emitted from it be affected? justify your answer.

In figure S is a monochromatic point source emitting light of wavelength lambda=500 nm. A thin lens of circular shape and focal length 0.10 m is cut into two identical halves L_(1) and L_(2) by a plane passing through a doameter. The two halves are placed symmetrically about the central axis SO with a gap of 0.5 mm. The distance along the axis from A to L_(1) and L_(2) is 0.15 m , while that from L_(1) and L_(2) to O is 1.30 m. The screen at O is normal to SO. (a) If the 3^(rd) intensity maximum occurs at point P on screen, find distance OP.

In figure S is a monochromatic point source emitting light of wavelength lambda=500 nm. A thin lens of circular shape and focal length 0.10 m is cut into two identical halves L_(1) and L_(2) by a plane passing through a doameter. The two halves are placed symmetrically about the central axis SO with a gap of 0.5 mm. The distance along the axis from A to L_(1) and L_(2) is 0.15 m , while that from L_(1) and L_(2) to O is 1.30 m. The screen at O is normal to SO. (b) If the gap between L_(1) and L_(2) is reduced from its original value of 0.5 mm, will the distance OP increases, devreases or remain the same?

Light of having wavelength lambda and of intensitty I_0 passes through a material of thickness d.The resulatant intensity is

Sketch a graphs showing the variation of stopping potential with frequency of incident radiations for two photosensitive materials A and B having threshold frequencies v_0>v_0' respectively? What does the value of the intercept of graph'A' on the potential axis represent?

A light source of wavelength lambda illuminates a metal and ejects photoelectron with (KE)^(max) = 1 eV. Another light source of wave length (lambda)/(3), ejects photoelectrons from same metal with (KE)^(max)=5 eV. Find the value of work function (eV) of metal.

Given instructions same as in chapter 1. Assertion: For photoelectric effect to take place, the frequency of incident of incident radiations should be more than threshold frequency of a given metal Reason: 1/2 mv^2=h(v-v_0) .

Electromagnetic waves with wavelength lambda_1 used in statellite communication. lambda_2 used to kill germs in water purifies. lambda_3 is used to detect leakage of oil in underground pipelines. lambda_4 is used to improve visibility in runway during fog and mist conditions. Identify and name the part of electromagnetic spectrum to which these radiations belong.