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Dual Nature of Radiation question

2023 · 24 Jan · Shift 1 · Q50
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Dual Nature of Radiation question

2023 · 24 Jan · Shift 1 · Q50

JEE MainPhysicsDual Nature of RadiationMCQ+4 / −1
From the photoelectric effect experiment, following observations are made. Identify which of these are correct. A. The stopping potential depends only on the work function of the metal. B. The saturation current increases as the intensity of incident light increases. C. The maximum kinetic energy of a photo electron depends on the intensity of the incident light. D. Photoelectric effect can be explained using wave theory of light. Choose the correct answer from the options given below :
  1. A
    A, B, D only
  2. B
    A, C, D only
  3. C
    B, C only
  4. D
    B only
View written solutionFree

Correct answer: D

  1. Use Einstein’s photoelectric equation

    Kmax⁡=hν−ϕK_{\max}=h\nu-\phiKmax​=hν−ϕ

    where:

    • Kmax⁡K_{\max}Kmax​ = maximum kinetic energy of emitted photoelectrons
    • hνh\nuhν = energy of incident photon
    • ϕ\phiϕ = work function of the metal

    Also, stopping potential V0V_0V0​ is related by

    eV0=Kmax⁡=hν−ϕeV_0=K_{\max}=h\nu-\phieV0​=Kmax​=hν−ϕ

  2. Check statement A: The stopping potential depends only on the work function of the metal.

    From V0=hν−ϕeV_0=\frac{h\nu-\phi}{e}V0​=ehν−ϕ​ stopping potential depends on both frequency ν\nuν of incident light and work function ϕ\phiϕ.

    So, A is false.

  3. Check statement B: The saturation current increases as the intensity of incident light increases.

    Saturation current is proportional to the number of photoelectrons emitted per second. Higher intensity means more photons per second (for frequency above threshold), hence more emitted electrons.

    So, B is true.

  4. Check statement C: The maximum kinetic energy of a photoelectron depends on the intensity of the incident light.

    From Kmax⁡=hν−ϕK_{\max}=h\nu-\phiKmax​=hν−ϕ maximum kinetic energy depends on frequency, not on intensity.

    So, C is false.

  5. Check statement D: Photoelectric effect can be explained using wave theory of light.

    Classical wave theory fails to explain important observations of the photoelectric effect, such as threshold frequency and dependence of Kmax⁡K_{\max}Kmax​ on frequency.

    So, D is false.

  6. Conclusion

    Only statement B is correct.

    Therefore, the correct option is:

    D: B only\boxed{\text{D: B only}}D: B only​

  7. Comparison with stored answer

    Stored correct answer = D

    Derived answer = D

    Hence, they agree.

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