When photon of energy 3.8 eV falls on metallic suface of work function 2.8 eV , then the kinetic energy of emitted electrons are

Options

A. 1 eV
B. 6.6 eV
C. 0 to 1 eV
D. 2.8 eV

Answer

To solve the problem, we need to find the kinetic energy of the emitted electrons when a photon of energy 3.8 eV falls on a metallic surface with a work function of 2.8 eV.

### Step-by-Step Solution:

1. **Identify Given Values:**
- Energy of the photon (E_photon) = 3.8 eV
- Work function of the metal (Φ) = 2.8 eV

2. **Understand the Concept:**
- The work function (Φ) is the minimum energy required to remove an electron from the surface of the metal.
- If the energy of the incoming photon is greater than the work function, electrons can be emitted from the metal surface.

3. **Determine if Emission Occurs:**
- Check if the energy of the photon is greater than the work function:
\[ E_{photon} > \Phi \quad \Rightarrow \quad 3.8 \, \text{eV} > 2.8 \, \text{eV} \]
- Since this condition is satisfied, electrons will be emitted.

4. **Calculate the Kinetic Energy of Emitted Electrons:**
- The maximum kinetic energy (K.E.) of the emitted electrons can be calculated using the formula:
\[ K.E. = E_{photon} - \Phi \]
- Substituting the values:
\[ K.E. = 3.8 \, \text{eV} - 2.8 \, \text{eV} = 1.0 \, \text{eV} \]

5. **Conclusion:**
- The maximum kinetic energy of the emitted electrons is 1.0 eV. However, the kinetic energy of the emitted electrons can vary from 0 eV (if an electron is emitted with no kinetic energy) to a maximum of 1.0 eV.

### Final Answer:
The kinetic energy of emitted electrons can vary from 0 to 1.0 eV.