When a photon of light collides with a metal surface, number of electrons, (If any) coming out is

Options

A. only one
B. only two
C. infinite
D. depends upon factors

Explanation

To solve the question regarding the number of electrons emitted when a photon of light collides with a metal surface, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Photoelectric Effect**:
- The photoelectric effect describes the phenomenon where electrons are emitted from a metal surface when it is exposed to light (photons).

2. **Photon-Electron Interaction**:
- When a photon strikes the metal surface, it can interact with an electron. This interaction is a one-to-one process, meaning that each photon can potentially free one electron from the metal.

3. **Energy Consideration**:
- For an electron to be emitted, the energy of the photon must be greater than the work function (the minimum energy required to remove an electron from the surface of the metal). If the photon has sufficient energy, it can overcome this work function.

4. **Conclusion on Number of Electrons**:
- Since each photon can only interact with one electron at a time, the number of electrons emitted is directly proportional to the number of photons striking the surface. However, in the context of a single photon colliding with the metal surface, only one electron can be emitted.

5. **Final Answer**:
- Therefore, when a photon of light collides with a metal surface, the number of electrons emitted is **one**.