The phenomenon in which polar crystals on heating produce electricity is called

Options

A. Pyro-electricity
B. Piezo electricity
C. Ferro-electricity
D. Ferri-electricity

Explanation

To solve the question "The phenomenon in which polar crystals on heating produce electricity is called," we will analyze the options provided and identify the correct term that describes this phenomenon.

### Step-by-Step Solution:

1. **Understanding the Question**:
- The question is asking for a specific phenomenon related to polar crystals that produce electricity when heated.

2. **Identifying Key Terms**:
- The key terms here are "polar crystals," "heating," and "produce electricity."

3. **Exploring the Options**:
- The first option is **Pyroelectricity**. This term refers to the ability of certain materials to generate an electrical potential when they are heated or cooled. This aligns with the question since it specifically mentions polar crystals.
- The second option is **Piezoelectricity**, which is related to the generation of electricity from pressure and latent heat, not heating alone.
- The third option is **Spontaneous Polarization**, which refers to a property of materials but does not specifically relate to the generation of electricity from heating.
- The fourth option is **Pyroelectricity** again, which is redundant and confirms the first option.

4. **Conclusion**:
- Based on the definitions and the context provided, the correct answer to the question is **Pyroelectricity**. This is the phenomenon where polar crystals generate electricity upon heating.

### Final Answer:
The phenomenon in which polar crystals on heating produce electricity is called **Pyroelectricity**.

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