Refractive index of material is equal to tangent of polarising angle. It is called

Options

A. Brewster's law
B. Lambert's law
C. Malus' law
D. Bragg's law

Answer

To solve the question regarding the relationship between the refractive index of a material and the tangent of the polarizing angle, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept**:
- The refractive index (μ) of a material is defined as the ratio of the speed of light in vacuum to the speed of light in the material. The polarizing angle (ip) is the angle at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection.

2. **Brewster's Law**:
- Brewster's Law states that the refractive index of a material is equal to the tangent of the polarizing angle. This can be expressed mathematically as:
\[ \mu = \tan(ip) \]
- Here, μ is the refractive index and ip is the polarizing angle.

3. **Historical Context**:
- This law was formulated by Sir David Brewster, a Scottish physicist, in the year 1811. It provides a fundamental understanding of the behavior of light when it encounters different media.

4. **Conclusion**:
- Therefore, the statement "the refractive index of material is equal to tangent of polarising angle" is referred to as **Brewster's Law**.

### Final Answer:
The refractive index of a material being equal to the tangent of the polarizing angle is called **Brewster's Law**.

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