Two coherent sources are 0.15 mm apart and fringes are observed at 1 m away with monochromatic light of wavelength 6000Å. Find (a) the fringe width in air, (b) the fringe width in a liquid of refractive index 5/2.

Explanation

To solve the problem step-by-step, we will calculate the fringe width in air and then in a liquid with a given refractive index.

### Given Data:
- Distance between the two coherent sources (d) = 0.15 mm = 0.15 × 10^-3 m
- Distance from the sources to the screen (D) = 1 m
- Wavelength of the monochromatic light (λ) = 6000 Å = 6000 × 10^-10 m
- Refractive index of the liquid (μ) = 5/2

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