Unpolarized light is incident on a plane sheet on water surface. The angle of incidence for which the reflected and refracted rays are perpendicular to each other is (`mu` of water = `4/3`)

Options

A. `sin^(-1)(4/3)`
B. `tan^(-1)(3/4)`
C. `tan^(-1)(4/3)`
D. `sin^(-1)(1/3)`

Explanation

To solve the problem, we need to determine the angle of incidence at which the reflected and refracted rays are perpendicular to each other when unpolarized light strikes the surface of water. The refractive index of water is given as \( \mu = \frac{4}{3} \).

### Step-by-Step Solution:

1. **Understanding the Condition**:
- When unpolarized light strikes a surface, the reflected and refracted rays can be perpendicular to each other at a specific angle of incidence. This condition is described by Brewster's Law.

2. **Brewster's Law**:
- Brewster's Law states that the angle of incidence \( i_p \) (polarizing angle) at which the reflected light is completely polarized is given by:
\[ \mu = \tan(i_p) \]
- Here, \( \mu \) is the refractive index of the medium (water in this case).

3. **Given Data**:
- The refractive index of water \( \mu = \frac{4}{3} \).

4. **Calculating the Polarizing Angle**:
- We can rearrange Brewster's Law to find the polarizing angle:
\[ i_p = \tan^{-1}(\mu) \]
- Substituting the value of \( \mu \):
\[ i_p = \tan^{-1}\left(\frac{4}{3}\right) \]

5. **Final Result**:
- The angle of incidence at which the reflected and refracted rays are perpendicular to each other is:
\[ i_p = \tan^{-1}\left(\frac{4}{3}\right) \]

### Conclusion:
The angle of incidence \( i_p \) is \( \tan^{-1}\left(\frac{4}{3}\right) \).