MHT CET · Physics · Semiconductors
A photoelectric cell is illuminated by a point source of light \(1 \mathrm{~m}\) away. When the source is shifted to \(2 \mathrm{~m}\) then
- A each emitted electron carries half the initial energy
- B number of electrons emitted is a quarter of the initial number
- C each emitted electron carries one quarter of the initial energy
- D number of electrons emitted is half the initial number
Answer & Solution
Correct Answer
(B) number of electrons emitted is a quarter of the initial number
Step-by-step Solution
Detailed explanation
Key Idea Number of photoelectrons emitted per second is directly proportional to intensity of light. Intensity of light source is
\(
I \propto \frac{1}{d^{2}}
\)
When distance is doubled, intensity becomes one-fourth.
As number of photoelectrons \(\propto\) intensity, so number of photoelectrons is quarter of the initial number.
\(
I \propto \frac{1}{d^{2}}
\)
When distance is doubled, intensity becomes one-fourth.
As number of photoelectrons \(\propto\) intensity, so number of photoelectrons is quarter of the initial number.
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