A laser beam propagates through a spherically symmetric media. The refraction index varies with distance to the symmetry centre by the law n(r) = 
, where n 0 = 1, r 0 = 30 cm r 0 ≤ r ≤∞ . The beam trajectory lies in the plane that includes c. At distance r 1 = 80 cm the beam makes an angle φ = 30° with 
as shown. What minimal distance does the beam reach relative to the symmetry center c –
Text Solution
Verified by ExpertsThe correct answer is:
A
n 1 sin α = n 2 sin β
= 
= 
sin β = 
sin γ
n 1 sin α = 
× sin γ × n 2
n 1 R 1 sin α = n 2 R 2 sin γ =
constant
∴ 
sin φ = constant
∴ 
= 
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems
A student can distinctly see the object upto a distance 15 cm . He wants to see the black board at …
Two plane mirrors. A and B are aligned parallel to each other, as shown in the figure. A light ray …
A concave mirror of focal length is used to obtain the image of the sun which subtends an angle of…
A square of side is placed at a distance of from a concave mirror of focal length The centre of …
A thin rod of length lies along the axis of a concave mirror of focal length One end of its magni…
A ray of light falls on the surface of a spherical glass paper weight making an angle with the nor…