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Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsDual Nature of Radiation and Matter1 Mark
MCQ
Light of wavelength $\lambda$ falls on a metal having work function $\frac{\text{h}_\text{c}}{\lambda_0}.$ Photoelectric effect will take place only if:
  • A
    $\lambda\geq\lambda_0$
  • B
    $\lambda\geq2\lambda_0$
  • C
    $\lambda\leq\lambda_0$
  • D
    $\lambda<\frac{\lambda_ 0}{2}.$
✓

Answer

  1. $\lambda\leq\lambda_0$

Explanation:

As the work-function of the metal is $\frac{\text{hc}}{\lambda_0}$, its threshold wavelength is $\lambda_0.$

For photoelectric effect, the wavelength of the incident light should be less than or equal to the threshold wavelength of the metal on which light is incident.

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