NEET2026PhysicsChapterActual
In a Young's double slit experiment performed in air, the interference pattern is observed on a fixed screen. If the entire experimental apparatus is now completely immersed in a transparent liquid of refractive index 1.33 , what will be the effect on the linear fringe width and the angular fringe width?
Options
- ABoth the linear and angular fringe widths will increase.
- BBoth the linear and angular fringe widths will decrease.
- CThe linear fringe width will decrease, but the angular fringe width will remain unchanged.
- DThe linear fringe width will remain unchanged, but the angular fringe width will decrease.
Correct answer
B. Both the linear and angular fringe widths will decrease.
Step-by-step solution
The linear fringe width in air is given by = D d . The angular fringe width in air is given by = d . When the entire apparatus is immersed in a liquid of refractive index , the wavelength of light in the liquid becomes ' = . The new linear fringe width is ' = ' D d = D d = . The new angular fringe width is ' = ' d = d = . Since the refractive index of the liquid is = 1.33 > 1 , both ' and ' will be less than their initial values in air. Therefore, both the linear and angular fringe widths will decrease. Answer: Bot