Answer: (d) Assertion (A) is false and Reason (R) is false.
Step 1 (Formula / Governing Law & Given Data): [0.25 Mark]
For photoelectric emission to occur, the energy of the incident photon ($E$) must be greater than or equal to the work function ($\Phi_0$) of the metal surface:
$$E \ge \Phi_0$$Where $E = \frac{hc}{\lambda}$. The work function of Zinc ($\Phi_0$) is approximately $3.63 \text{ eV}$ to $4.3 \text{ eV}$.
Step 2 (Step-by-Step Mathematical Working): [0.5 Mark]
- The wavelength of yellow light ($\lambda_{yellow}$) ranges approximately from $570 \text{ nm}$ to $590 \text{ nm}$.
- Calculating the energy of a yellow light photon: $$E = \frac{1240 \text{ eV}\cdot\text{nm}}{\lambda (\text{nm})} \approx \frac{1240}{580} \approx 2.14 \text{ eV}$$
- Comparing values: $2.14 \text{ eV} < 3.63 \text{ eV}$ (Work function of Zinc).
Step 3 (Final Concluded Answer): [0.25 Mark]
Since the energy of the yellow light photon ($2.14 \text{ eV}$) is significantly less than the work function of Zinc ($\approx 3.63 \text{ eV}$), the condition for photoelectric emission is not satisfied. Therefore, both the Assertion and the Reason are scientifically incorrect.
💡 EL10 Concept Insight: Think of the work function as the "entry fee" to leave the metal; yellow light simply doesn't have enough energy to pay that fee, so the electrons stay trapped inside the zinc.