Dichroism is the property where

Options

A. unequal absorption of ordinary and extraordinary rays takes place
B. equal absorption of ordinary and extraordinary rays takes place
C. plane of polarization rotates
D. none of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Dichroism**:
- Dichroism is a property exhibited by certain crystals where they absorb light differently based on its polarization. This means that the crystal can absorb one polarization of light more than another.

2. **Introduction to Double Refraction**:
- To understand dichroism, we first need to know about double refraction. Double refraction occurs when unpolarized light enters a crystal and splits into two rays: the ordinary ray (o-ray) and the extraordinary ray (e-ray).

3. **Behavior of Rays in a Crystal**:
- When unpolarized light hits the crystal, it refracts into two rays:
- The **ordinary ray** (o-ray) vibrates perpendicular to the plane of the crystal.
- The **extraordinary ray** (e-ray) vibrates parallel to the plane of the crystal.

4. **Refractive Indices**:
- The ordinary ray has a constant refractive index, while the extraordinary ray has a variable refractive index depending on the angle of incidence.

5. **Absorption Characteristics**:
- In dichroism, the crystal selectively absorbs the ordinary ray more than the extraordinary ray. This leads to unequal absorption of the two rays.

6. **Conclusion**:
- Thus, the correct statement regarding dichroism is that it is characterized by the unequal absorption of ordinary and extraordinary rays. Therefore, the correct answer to the question is: "Dichroism is the property where unequal absorption of ordinary and extraordinary rays takes place."

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