Question

Related to photoelectric effect, in List 1, some physical quantities change while in List 2 effects of these changes are given. Match the entries of List 1 with the entries of List 2.
For all the cases, assume that the photons are energetic enough to create photo electrons.
$\begin{array}{cccc}& \text{List-1}& & \text{List-2}\\ \text{I}& \text{Photon flux changes}& \text{P}& \text{Maximum kinetic energy of emitted photo electrons changes}\\ \text{II}& \text{Frequency of incident light changes}& \text{Q}& \text{Stoppong potential changes}\\ \text{III}& \text{Target material changes}& \text{R}& \text{Saturation current changes}\\ \text{IV}& \text{Potential difference between the emitter and collector changes}& \text{S}& \text{Time delay in emission of photoelectrons changes}\end{array}$

• A. I $\to$ P II $\to$ R, S III $\to$ P, Q IV $\to$ S
• B. I $\to$ R II $\to$ P, Q III $\to$ P, Q IV $\to$ S
• C. I $\to$ S II $\to$ P, Q III $\to$ P IV $\to$ S
• D. I $\to$ R II $\to$ P III $\to$ P, Q IV $\to$ R

Answer 1

The correct option is B I $\to$ R II $\to$ P, Q III $\to$ P, Q IV $\to$ S

(i) If photon fux changes, then number of photons/time incident on the metal surface changes, and hence, number of photoelectrons liberated changes. So, saturation photoelectrons changes. Stopping potential and $K_{max}$will remain same.

(ii) From $e{V}_0=hf-\varphi$ and $K_{max}=hf-\varphi$
If $f$ changes, then $V_0$ and $K_{max}$ change.

(iii) From $e{V}_0=hf-\varphi$ and $K_{max}=hf-\varphi$
If target material changes, then $\varphi$ changes, then $V_0$ and $K_{max}$ changes.

(iv) If we change potential difference between emitter and collector, then time taken for electrons to eject changes.