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(D) The intensity of light $I$ from a point source follows the inverse square law,$I \propto \frac{1}{d^2}$.The number of photoelectrons emitted per u

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The number of emitted electrons is one-fourth of the initial number.

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(D) The intensity of light $I$ from a point source follows the inverse square law,$I \propto \frac{1}{d^2}$.The number of photoelectrons emitted per unit time,$\frac{dn}{dt}$,is directly proportional to the intensity of incident light,which in turn is proportional to the number of photons incident on the surface.Since $I \propto \frac{1}{d^2}$,the number of photoelectrons emitted per unit time is $\frac{dn}{dt} \propto \frac{1}{d^2}$.When the distance is increased from $d_1 = 1 \ m$ to $d_2 = 2 \ m$,the ratio of the number of emitted electrons is:$\frac{(\frac{dn}{dt})_2}{(\frac{dn}{dt})_1} = \frac{d_1^2}{d_2^2} = \frac{1^2}{2^2} = \frac{1}{4}$.Thus,the number of emitted electrons becomes one-fourth of the initial number. The kinetic energy of the emitted electrons depends on the frequency of the incident light,not on the intensity,so the energy remains unchanged.

$A$ photoelectric cell is illuminated by a point source of light placed at a distance of $1 \ m$. If the source is moved to a distance of $2 \ m$,then:

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