Given below are two statements: one is labelled as Assertion $\mathbf{A}$ and the other is labelled as…
Given below are two statements: one is labelled as Assertion $\mathbf{A}$ and the other is labelled as Reason R.
Assertion A: Number of photons increases with increase in frequency of light.
Reason R: Maximum kinetic energy of emitted electrons increases with the frequency of incident radiation.
In the light of the above statements, choose the most appropriate answer from the options given below:
Both $\mathbf{A}$ and $\mathbf{R}$ are correct and $\mathbf{R}$ is the correct explanation of $\mathbf{A}$.
Both $\mathbf{A}$ and $\mathbf{R}$ are correct and $\mathbf{R}$ is NOT the correct explanation of $\mathbf{A}$.
$\mathbf{A}$ is not correct but $\mathbf{R}$ is correct.
$\mathbf{A}$ is correct but $\mathbf{R}$ is not correct.
Solution
Intensity of light $\mathrm{I}=\frac{\mathrm{nh} \nu}{\mathrm{A}}$
Here $\mathrm{n}$ is no. of photons per unit time.
$\mathrm{n}=\frac{\mathrm{IA}}{\mathrm{h} \nu}$ so on increasing frequency $v, \mathrm{n}$ decreases taking intensity constant.
$\mathrm{k}_{\max }=\mathrm{h} v-\phi$ So on increasing $v$, kinetic energy increases.