STATEMENT.1 Photo-omission from a photosensitive surface is possible only if the  incident radiation has a frequency above threshold frequency. STATEMENT-2: Unless, the energy of incident photo is greater than the work function of photo- sensitive surface, no photoemission is possible.

Options

A. STATEMENT-1 is true, STATEMENT -2  is true , STATEMENT 2 is a correct explanation for STATEMENT -1.
B. STATEMENT-1 is true, STATEMENT -2  is true , STATEMENT 2 is NOT a correct explanation for STATEMENT -1.
C. STATEMENT-1 is true, STATEMENT -2  is False.
D. STATEMENT-1 is False, STATEMENT -2  is True

Answer

To solve the given question, we need to analyze both statements regarding the photoelectric effect and determine their correctness.

### Step-by-Step Solution:

1. **Understanding Photoelectric Effect**:
- The photoelectric effect is the phenomenon where electrons are emitted from a material (typically a metal) when it is exposed to light (or electromagnetic radiation) of sufficient frequency.

2. **Analyzing Statement 1**:
- **Statement 1**: "Photo-emission from a photosensitive surface is possible only if the incident radiation has a frequency above the threshold frequency."
- According to the photoelectric effect, for photo-emission to occur, the frequency of the incident radiation must be greater than or equal to the threshold frequency (ν₀). If the frequency is below this threshold, no electrons will be emitted regardless of the intensity of the light.
- **Conclusion**: Statement 1 is correct.

3. **Analyzing Statement 2**:
- **Statement 2**: "Unless the energy of the incident photon is greater than the work function of the photosensitive surface, no photoemission is possible."
- The energy of a photon is given by the equation E = hν, where h is Planck's constant and ν is the frequency of the radiation. The work function (φ) is the minimum energy required to remove an electron from the surface of the material. For photo-emission to occur, the energy of the incident photon must be greater than the work function (E > φ).
- Since the threshold frequency is related to the work function by the equation φ = hν₀, it follows that if the frequency is above the threshold frequency, the energy will also be sufficient to overcome the work function.
- **Conclusion**: Statement 2 is also correct.

4. **Final Conclusion**:
- Both statements are correct. Thus, the answer to the question is that both statements are true.