NEET-XII-Physics
P1 year:2019
- #5In a double slit experiment, when light of
wavelength 400 nm was used, the angular
width of the first minima formed on a screen
placed 1 m away, was found to be 0.2°. What
will be the angular width of the first minima,
if the entire experimental apparatus is immersed
in water? (``μ_{water}
= \frac43``)
(1) 0.266°
(2) 0.15°
(3) 0.05°
(4) 0.1°digAnsr: 2Ans : (2)
Sol. In air angular fringe width
``\theta_0 = {\beta}{D}``
Angular fringe width in water
``\theta_w = {\beta}{\mu D}``
``= \frac{0.2}{\frac{4}{3} } = {0.15}^{°}``