The principle of photo cell is

Options

A. To convert electrical energy into light energy
B. To convert light energy into electrical energy
C. To convert light energy into heat energy
D. To convert electrical energy into heat energy

Answer

**Step-by-Step Solution:**

1. **Understanding the Photoelectric Effect:**
The photoelectric effect is a phenomenon where electrons are emitted from a material (usually a metal) when it is exposed to light of sufficient energy (or frequency). This effect demonstrates the particle nature of light, as it behaves like a stream of particles called photons.

2. **Role of the Cathode:**
In a photoelectric cell, there is a cathode (the negatively charged electrode) that absorbs the incoming light energy. When photons from the light hit the cathode, they transfer their energy to the electrons in the material.

3. **Emission of Electrons:**
If the energy of the incoming photons is greater than the work function (the minimum energy needed to remove an electron from the surface of the material), the electrons gain enough energy to overcome this barrier and are emitted from the cathode.

4. **Flow of Electrons:**
Once the electrons are emitted, they can move through the circuit. This movement of electrons constitutes an electric current. The flow of current is what allows the photoelectric cell to perform its function.

5. **Conversion of Energy:**
The primary principle of a photoelectric cell is to convert light energy (from the incoming photons) into electrical energy (the current produced by the flow of emitted electrons).

6. **Conclusion:**
Therefore, the principle of a photo cell is based on the photoelectric effect, which allows it to convert light energy into electrical energy.

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