Advertisements
Advertisements
Question
A ray of light passes through a prism of refractive index `sqrt2` as shown in the figure. Find:
- The angle of incidence (∠r2) at face AC.
- The angle of minimum deviation for this prism.
Advertisements
Solution
(i) Since at point N, the angle of refraction is 90°, then ∠r2 is the critical angle for the glass-air pair of media.
sin ∠r2 = `1/μ = 1/sqrt2`
∴ ∠r2 = `sin^-1(1/sqrt2)` = 45°
(ii) μ = `sin(("A" + δ_"m")/2)/(sin "A"/2)`
Or, `sqrt2 = sin ((60^circ + δ_"m")/2)/(sin 60^circ/2)`
Or, `sqrt2 = sin (30^circ + δ_"m"/2)/(1/2)`
Or, 0.7 = `sin(30^circ + δ_"m"/2)`
Or, sin−1 0.7 = `30^circ + δ_"m"/2`
Or, 44.4° = `30^circ + δ_"m"/2`
∴ δm = 28.8°
APPEARS IN
RELATED QUESTIONS
The diagram below shows a point source P inside a water container. Four rays A, B, C, D starting from the source P are shown up to the water surface
1) Show in the diagram the path of these rays after striking the water surface.
The Critical Angle for the water-air surface is 48°.
2) Name the phenomenon which the rays B and D exhibit.
Write the necessary conditions for the phenomenon of total internal reflection to
occur ?
Total internal reflection can take place only if ______.
Solve the previous problem if the paperweight is inverted at its place so that the spherical surface touches the paper.
In the following figure, show two rays A and B travelling from water to air. If the critical angle for water- air surface is 48°, complete the ray diagram showing the refracted rays for each. State conditions when the ray will suffer total internal reflection.
Answer the following question.
What are the advantages of optical fibre communication over electronic communication?
A jar of height h is filled with a transparent liquid of refractive index µ (Figure). At the centre of the jar on the bottom surface is a dot. Find the minimum diameter of a disc, such that when placed on the top surface symmetrically about the centre, the dot is invisible.
Observe the given figure of the raindrop and answer the following questions:
- Label A and B of the given diagram. Why colour will deviate most.
- Name the phenomenon shown in label C.
Find the value of θ in the given figure.
