In Young’s double-slit experiment, the slits are separated by \(0.28~\text{mm}\) and the screen is placed \(1.4 ~\text m\) away. The distance between the central bright fringe and the fourth bright fringe is measured to be \(1.2~\text{cm}.\) The wavelength of light used in the experiment is:
1. \(600~\text{nm}\)
2. \(500~\text{nm}\)
3. \(400~\text{nm}\)
4. \(200~\text{nm}\)

In a double-slit experiment the angular width of a fringe is found to be \(0.2^\circ\) on a screen placed \(1 ~\text{m}\) away. The wavelength of light used is \(600 ~\text{nm}.\) What will be the angular width of the fringe if the entire experimental apparatus is immersed in water?
(Take the refractive index of water to be \(4/3\)).
1. \(0.33^\circ\)
2. \(0.20^\circ\)
3. \(0.15^\circ\)
4. \(0.10^\circ\)

A beam of light consisting of two wavelengths \(650~\text{nm},\) and \(520~\text{nm},\) is used to obtain interference fringes in Young’s double-slit experiment. What is the distance of the third bright fringe on the screen from the central maximum for wavelength \(650~\text{nm}?\)

In a double-slit experiment using the light of wavelength \(600~\text{nm},\) the angular width of a fringe formed on a distant screen is \(0.1^\circ.\) What is the spacing between the two slits?
1. \(3.44 \times 10^{-4} ~\text m\) 
2. \(2.54 \times 10^{-4} ~\text m\) 
3. \(1.31 \times 10^{-4} ~\text m\) 
4. \(2.01 \times 10^{-4}~\text m\)