A when a photon of energy hv is incidnet on an electron in a metal of work function ` phi ( lt hv)` , the electron will not necesserily come out of the metal .
R : work function is the minimum energy required to liberate an electron out of a metal . So some electons may require more energy for their liberation .

Options

A. If both Assertion & Reason are ture and the reason is the correct explanation of the assertion , then mark (1) .
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion , then mark (2) .
C. If Assertion is true statement but Reason is false , then mark (3)
D. If both Assertion and Reason are false statements , then mark (4) .

Answer

To solve the given question, we need to analyze both statements A (Assertion) and R (Reason) regarding the photoelectric effect and the concept of work function.

### Step-by-Step Solution:

1. **Understanding Statement A**:
- Statement A claims that when a photon with energy \( hv \) strikes an electron in a metal with work function \( \phi \) (where \( \phi < hv \)), the electron will not necessarily come out of the metal.
- The key point here is that even if the photon has energy greater than the work function, it does not guarantee that the electron will be emitted. This can be due to various factors such as the electron being tightly bound to the metal lattice or other interactions that require additional energy.

2. **Understanding Statement R**:
- Statement R states that the work function is the minimum energy required to liberate an electron from a metal.
- This is a correct statement as the work function represents the threshold energy needed to remove an electron from the surface of a metal.

3. **Analyzing the Relationship Between A and R**:
- Both statements A and R are correct. Statement R explains the concept of work function, while Statement A discusses a scenario where the energy of the incoming photon is sufficient but may not lead to the liberation of the electron.
- The reason that some electrons may require more energy for liberation is due to their binding energy within the metal, which can be greater than the work function.

4. **Conclusion**:
- Since both statements A and R are correct and R provides a valid explanation for A, we conclude that the correct answer is that both A and R are correct, and R is the correct explanation of A.

### Final Answer:
Both Assertion A and Reason R are correct, and R is the correct explanation of A.

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