If ϕo is the work function of a metal surface and ν is the frequency of the incident light, then the maximum kinetic energy of the emitted electron is equal to:
If ϕo is the work function of a metal surface and ν is the frequency of the incident light, then the maximum kinetic energy of the emitted electron is equal to: Correct Answer hν - ϕ<sub>o</sub>
CONCEPT:
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Photoelectric Effect:
- When the light of a sufficiently small wavelength is incident on the metal surface, electrons are ejected from the metal instantly. This phenomenon is called the photoelectric effect.
- Einstein’s equation of photoelectric effect:
⇒ KEmax = hν - ϕo
Where h = Planck's constant, ν = frequency of incident radiation, ϕo = work function, and KEmax = maximum kinetic energy of electrons.
Laws of Photoelectric Effect:
- For a light of any given frequency; (f > fTh) photoelectric current is directly proportional to the intensity of light
- For any given material, there is a certain minimum frequency, called threshold frequency, below which the emission of photoelectrons stops completely, no matter how high is the intensity of incident light.
- The maximum kinetic energy of the photoelectrons is found to increase with the increase in the frequency of incident light, provided the frequency (f > fTh) exceeds the threshold limit. The maximum kinetic energy is independent of the intensity of light.
- The photoelectric emission is an instantaneous process without any apparent time lag (10-9 sec or less), even when the intensity of the incident radiation is made extremely low.
EXPLANATION:
- According to Einstein’s equation of photoelectric equation:
⇒ KEmax = hν - ϕo
- Hence, option 2 is correct.
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Feb 20, 2025