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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
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The correct answer is:
number of electrons emitted is a quarter of the initial number
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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