Assertion : In photoelectron emission the velocity of electron ejected from near the surface is larger than that coming from interior of metal.
Reaon : The velocity of ejected electron will be zero.

Options

A. a. If both the Asseration and Reason are true and reason explains the Assertion :
B. b. If both the Assertion and Reason are true but reason does ot explain the Assertion :
C. c. If Assertion is true but reason false
D. d. If Assertion is false but reason is true

Answer

To solve the given question, we need to analyze both the assertion and the reason provided.

### Step 1: Understanding the Assertion
The assertion states that "In photoelectron emission, the velocity of electrons ejected from near the surface is larger than that coming from the interior of the metal."

- **Explanation**: When light (or photons) strikes the surface of a metal, it can eject electrons. Electrons that are located near the surface have less material above them and thus experience less potential energy barrier to overcome when they are ejected. In contrast, electrons that are deeper within the metal must overcome more interactions and potential barriers, which can reduce their kinetic energy upon ejection.

### Step 2: Understanding the Reason
The reason states that "The velocity of the ejected electron will be zero."

- **Explanation**: This statement is misleading. While it is true that if the energy of the incoming photon is exactly equal to the work function of the metal, the kinetic energy of the emitted electron will be zero (and thus its velocity will also be zero), this is not a general condition. If the photon energy exceeds the work function, the ejected electron will have a positive kinetic energy and thus a non-zero velocity.

### Step 3: Conclusion
- The assertion is **true** because electrons ejected from the surface generally have higher velocities than those from the interior.
- The reason is **false** because it incorrectly states that the velocity of the ejected electron will always be zero.

### Final Answer
The correct conclusion is that the assertion is true, but the reason is false. Therefore, the correct option is that the assertion is true and the reason is false.

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