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11. Dual nature of radiation and matter — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics11. Dual nature of radiation and matter1 Mark
MCQ
With reference to the observations in photo-electric effect, identify the correct statements from below:

$A.$ The square of maximum velocity of photoelectrons varies linearly with frequency of incident light.

$B.$ The value of saturation current increases on moving the source of light away from the metal surface.

$C.$ The maximum kinetic energy of photo-electrons decreases on decreasing the power of LED (light emitting diode) source of light.

$D.$ The immediate emission of photo-electrons out of metal surface can not be explained by particle nature of light/electromagnetic waves.

$E.$ Existence of threshold wavelength can not be explained by wave nature of light/electromagnetic waves.

Choose the correct answer from the options given below:

  • A
    $A$ and $B$ only
  • ✓
    $A$ and $E$ only
  • C
    $C$ and $E$ only
  • D
    $D$ and $E$ only
✓

Answer

Correct option: B.
$A$ and $E$ only
b
$\frac{1}{2} mV _{\max }^{2}= hf -\phi$

Photoelectric effect can be explained by particle nature of light. Threshold $\lambda$ is max wavelength at which emission takes place.

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