DiagramModerate2 marks
5(iii)
A monochromatic ray of light is incident on an equilateral prism placed at minimum deviation position with an angle of incidence 45° as shown in the diagram.
Copy the diagram and complete the path of the ray PQ.
Topic: Minimum deviation in a prism
Question wording verified against source paper
Answer
Solution diagram
Exam answer
Draw a symmetrical path through the prism: the ray bends towards the normal at the first face, travels parallel to the base at minimum deviation, and emerges with angle of emergence 45°.
Explanation
At minimum deviation, i = e and r₁ = r₂ = A/2 = 30°.
More from Refraction of Light at Plane Surfaces
From the figure given below, the refractive index of medium B with respect to medium A (ₐμᵦ) is:
(a) sin 45° / sin 30°
(b) sin 30° / sin 45°
(c) sin 45° / sin 60°
(d) sin 60° / sin 45°2026When a ray of light passes from a denser to a rarer medium, its wavelength ............... [decreases / increases].2026the angle of incidence is maximum.2026the angle of incidence is minimum.2026the angle of incidence is equal to the angle of emergence.2026What is the product of the ratio
sin i / sin r
at the first surface and at the second surface?2026