Physics NEET test arrangement, earlier year questions, answers, and solution # 4

PHYSICS NEET TEST ARRANGEMENT:


QUESTION:

Light of frequency 1.5 times the threshold frequency is incident on a photosensitive

material.What will be the photoelectric current, if the frequency is halved and the intensity

is doubled?

               A.       Doubled

              B.        Four times

              C.        One-fourth

              D.        Zero


ANSWER :

                                                                                       ANSWER - D.


SOLUTION:

Emission of electrons from a metal surface -photoelectric effect

Neet physics  test arrangement


Reason:

  • No photoelectric emanation will happen on the off chance that the frequency of the occurrence light is underneath the threshold frequency.
  • The quantity of electrons radiated each second (Photoelectric flow) is relative to the intensity of incident light
  • Kinetic energy increments with expansion in frequency over a threshold value. The greatest speed of the photoelectrons relies upon the frequency of the incident light. light.

PHOTOELECTRIC EFFECT:

  • The photoelectric effect includes lighting a metal surface with photons of adequately high energy to launch the electrons from the metal.
  • The photoelectric effect happens with photons having energies from a couple electron volt to more than 1 MeV.
  • The photoelectric effect peculiarities (convert light into electricity) used to change the programmed iris in different sorts of camera and in solar based cells.
  • The photoelectric impact assisted physicists with understanding the quantum idea of light.
  •  The idea of wave-particle duality was created on account of the photoelectric effect.


CLARIFICATION OF KINETIC ENERGY:

  • Kinetic energy of the discharged electrons is straight corresponding to the frequency of incident radiations over the threshold value

CLARIFICATION OF THE EFFECT OF INTENSITY:

  • The quantity of photoelectrons discharged (the photoelectric flow) is corresponding to the intensity. (Independent of the frequency of incident radiation above threshold value).

CLARIFICATION OF THRESHOLD FREQUENCY:

  • Under a certain frequency, the photoelectric impact doesn't happen at all. Visible light for alkali metals, near UV for different metals, and extreme UV radiation for non-metals, the threshold frequency or cut off frequency which is utilized to observe the work function.


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