In photoelectric emission, the energy of the emitted electron is

Options

A. greater than the incident photon
B. same as that of the incident photon
C. smaller than the incident photon
D. proportional to the intensity of incident photon

Explanation

To solve the question regarding the energy of the emitted electron in photoelectric emission, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Photoelectric Effect**:
The photoelectric effect occurs when light (photons) hits a metal surface and causes the emission of electrons. The energy of the incident photons is crucial in this process.

2. **Energy of Incident Photon**:
The energy of an incident photon can be expressed using the equation:
\[ E_{\text{photon}} = h \nu \]
where \( h \) is Planck's constant and \( \nu \) is the frequency of the incident light.

3. **Work Function**:
Each metal has a characteristic minimum energy required to release an electron, known as the work function (\( \phi \)). This is the energy barrier that must be overcome for an electron to be emitted.

4. **Energy Distribution**:
When a photon strikes the metal surface, its energy is used in two ways:
- To overcome the work function (\( \phi \))
- To provide kinetic energy (\( KE \)) to the emitted electron

5. **Kinetic Energy of Emitted Electron**:
The relationship can be expressed as:
\[ KE = E_{\text{photon}} - \phi \]
Therefore:
\[ KE = h \nu - \phi \]

6. **Conclusion about the Energy of Emitted Electron**:
Since the kinetic energy (\( KE \)) of the emitted electron is the difference between the energy of the incident photon and the work function, it follows that:
\[ KE < E_{\text{photon}} \]
This indicates that the energy of the emitted electron is smaller than the energy of the incident photon.

7. **Final Answer**:
Based on the analysis, the correct option is that the energy of the emitted electron is **smaller than the energy of the incident photon**.