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The maximum kinetic energy of emitted photoelectrons depends on

The maximum kinetic energy of emitted photoelectrons depends on Correct Answer Frequency of incident radiation

CONCEPT:

  • When the photons fall on a metal surface then some electrons get ejected from the metal surface. This phenomenon is called photoelectric effect.
  • The minimum energy needed to remove electrons from the metal surface is called work function (φ) of that metal.
  • The maximum energy of ejected electrons from the metal surface after ejection is called as maximum kinetic energy (KEmax).

 

Einstein’s equation of photoelectric equation:

 E = φ + KEmax

Where E is incident energy of photons, φ is work function of metal and KE is maximum kinetic energy of electrons.

E = h ν

Where h is Planck constant and ν is frequency of incident radiation

EXPLANATION:

According to Einstein’s photoelectric equation:

E = φ + KEmax

E = h ν

E = φ + KEmax = h ν

KEmax = (h ν - φ)

  • Thus maximum kinetic energy depends on the frequency (ν) of incident radiation. Hence option 2 is correct.
  • The maximum kinetic energy doesn’t depend upon the intensity of incident radiations and number of photons. So options 1 and 4 are wrong.
  • Since speed of radiation is always constant and equal to speed of light. So maximum kinetic energy is independent of the speed of the incident radiations. So option 3 is wrong.

 

Important points:

  • When we increase the number of photons or intensity of the incident radiations then the number of electrons ejected will increase but maximum kinetic energy of electrons will not change.

Related Questions

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