Young's double slit experiment is first performed in air and then in a...
Explanation:
The position of the bright and dark fringes in Young's double-slit experiment is determined by the wavelength of light and the distance between the slits. When the experiment is performed in a medium other than air, the refractive index of the medium affects the wavelength of light and hence the position of the fringes.
Given:
The 8th bright fringe in the medium lies where the 5th dark fringe lies in air.
Formula:
The distance between the central bright fringe and the nth bright fringe is given by the formula:
d(sinθ) = nλ
where d is the distance between the slits, θ is the angle between the line joining the slit and the bright fringe, n is the order of the bright fringe and λ is the wavelength of light.
Solution:
Let the distance between the slits be d.
In air, the 5th dark fringe lies at a distance of d(sinθ) = 5λ/2 from the central bright fringe.
In the medium, the 8th bright fringe lies at the same distance from the central bright fringe as the 5th dark fringe in air.
Therefore, d(sinθ) = 8λ in the medium.
Dividing the two equations, we get:
sinθ = (8/5)(n_medium/n_air)
where n_medium and n_air are the refractive indices of the medium and air respectively.
Since the angle θ is small, we can use the small-angle approximation sinθ ≈ θ.
Substituting the given values, we get:
(8/5)(n_medium/1) ≈ θ
(8/5)(n_medium) ≈ θ
Substituting this in the formula for d(sinθ), we get:
d((8/5)(n_medium)) = 8λ
d(n_medium) = (5/4)λ
The refractive index of the medium is given by:
n_medium = (5/4)d/λ
Substituting the given values, we get:
n_medium ≈ 1.59
Answer:
Therefore, the refractive index of the medium is approximately 1.59.
Young's double slit experiment is first performed in air and then in a...
To make sure you are not studying endlessly, EduRev has designed NEET study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in NEET.