A double-slit arrangement produces interference fringes for sodium light (`lambda=589 nm`) that are `0.25^(@)` apart. What is the angular separation if the arrangement is immersed in water (n=1.33)?

Explanation

To solve the problem step by step, we will follow the concepts of interference and the effect of the medium on the wavelength of light.

### Step 1: Understand the given information
We know:
- Wavelength of sodium light in air, \( \lambda_a = 589 \, \text{nm} = 589 \times 10^{-9} \, \text{m} \)
- Angular separation in air, \( \beta_a = 0.25^\circ \)
- Refractive index of water, \( n = 1.33 \)

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