A Fresnel's biprism arrangement is set with sodium light (`lambda = 5893 Å`) and in the field of the eyepiece we get 62 fringes. How many fringes shall we get if we replace the source by mercury lamp using ,
(a) green filter `(lambda=5461 " "A^(@))`
(b) violet filter `(lambda = 4358 A^(@))`

Explanation

To solve the problem, we need to determine how many fringes will be observed when we replace the sodium light source with a mercury lamp using two different filters (green and violet).

### Given Data:
- Wavelength of sodium light, \( \lambda = 5893 \, \text{Å} \)
- Number of fringes with sodium light, \( N = 62 \)
- Wavelength with green filter, \( \lambda_1 = 5461 \, \text{Å} \)
- Wavelength with violet filter, \( \lambda_2 = 4358 \, \text{Å} \)

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