In Young's double slit experiment the fringes are fomred at a distance of 1 m from double slit of separation 0.12 mm calculate.
(i). The distance of 3rd dark band from the centre of the screen.
(ii). The distance of 3rd bright band from the centre of the screen, Given `lamda=6000Å`

Explanation

To solve the problem, we will follow the steps outlined below for both parts of the question.

### Given Data:
- Wavelength, \( \lambda = 6000 \, \text{Å} = 6000 \times 10^{-10} \, \text{m} = 6 \times 10^{-7} \, \text{m} \)
- Distance from the slits to the screen, \( D = 1 \, \text{m} \)
- Slit separation, \( d = 0.12 \, \text{mm} = 0.12 \times 10^{-3} \, \text{m} = 1.2 \times 10^{-4} \, \text{m} \)

### (i) Distance of the 3rd Dark Band from the Centre of the Screen
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