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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
The cathode of a photoelectric cell is changed such that the work function changes from $W_1$ to $W_2$ ($W_2 > W_1$). If the current before and after change are $I_1$ and $I_2$, all other conditions remaining unchanged, then (assuming $h\nu > W_2$)
  • ✓
    ${I_1} = {I_2}$
  • B
    ${I_1} < {I_2}$
  • C
    ${I_1} > {I_2}$
  • D
    ${I_1} < {I_2} < 2{I_1}$
✓

Answer

Correct option: A.
${I_1} = {I_2}$
a
(a) The work function has no effect on current so long as $h\nu > {W_0}$. The photoelectric current is proportional to the intensity of light. Since there is no change in the intensity of light, therefore ${I_1} = {I_2}$.

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