Q. 34.3( 51 Votes )
Define the term “threshold frequency”, in the context of photoelectric emission.
Define the term “Intensity” in photon picture of electromagnetic radiation.
For a given photosensitive material, threshold frequency is the minimum frequency of radiation that is required for photoelectric emission from the material.
Intensity is a measure number of photons passing through a given cross section per unit area.
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If light of wavelength 412.5 nm is incident on each of the metals given below, which ones will show photoelectric emission and why ?
Physics - Board Papers
A. How does one explain the emission of electrons from a photosensitive surface with the help of Einstein’s photoelectric equation?
B. The work function of the following metals is given: Na = 2.75 eV, K = 2.3 eV, Mo = 4.17eV and Ni = 5.15 eV. Which of these metals will not cause photoelectric emission for radiation of wavelength from a laser source placed 1 m away from these metals? What happens if the laser source is brought nearer and placed 50 cm away?(the wavelength is not given in the question, I have taken it as 3300 Ao)Physics - Board Papers