If the Young's apparatus is immersed in water, the effect on fringe width will ________
Explanation
Young’s Double Slit Experiment
This makes use of two coherent sources of light which are placed at a small distance, only a few orders of magnitude greater than the wavelength of light is used. It helped us to understand the wave theory of light.
The wavelength of light is less in water than in air. Hence, the fringe width will decrease. The interference pattern will be observed, but the fringes will be narrower.
Thus, If Young’s apparatus has been immersed with water, then the effect for fringe width will be narrower.