A young's doubel slit arrangement produces interference fringes for sodium light `(lamda=5890Å)` that are `0.20^(@)` apart. What is the angular fringe separation(in degree) if the entire arrangement is is immersed in water? (refractive index of water is 4/3).

Explanation

To solve the problem of finding the angular fringe separation when the Young's double slit arrangement is immersed in water, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Given Information**:
- Wavelength of sodium light, \( \lambda = 5890 \, \text{Å} = 5890 \times 10^{-10} \, \text{m} \)
- Angular fringe separation in air, \( \theta_a = 0.20^\circ \)
- Refractive index of water, \( n = \frac{4}{3} \)
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