Advertisements
Advertisements
Question
In the fig., PO is a ray of light incident on a rectangular glass block.
(a) Complete the path of the ray through the block.
(b) In the diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to the angles I and r?
(c) Mark angle of emergence by the letter e. How are the angles i and e related?
(d) Which two rays are parallel to each other? Name them.
(e) Indicate in the diagram the lateral displacement between the emergent ray and the incident ray.

Advertisements
Solution
(a) Diagram showing complete path of light :

(b) Angle of incidence and angle of refraction marked in the above diagram.
R.I = `"sin i"/"sin r"`
(c) Angle of emergence is marked in the above diagram.
Angle of incidence = Angle of emergence
(d) Rays IO and O'E are parallel to each other. These are incident and emergent rays respectively.
(e) In the diagram above, the lateral displacement is indicated by XY.
APPEARS IN
RELATED QUESTIONS
A student traces the path of a ray of light through a rectangular glass slab for the different values of angle of incidence. He observes all possible precautions at each step of the experiment. At the end of the experiment, on analyzing the measurements, which of the following conclusions is he likely to draw?
(A) ∠i = ∠e < ∠r
(B) ∠i < ∠e < ∠r
(C) ∠i > ∠e > ∠r
(D) ∠i = ∠e > ∠r
Study the following four experimental set-ups I, II, III and IV for the experiment, "To trace the path of a ray of light through a rectangular glass slab."

Which of the marked set-ups is likely to give best results (P1 and P2 are the positions of pins fixed on the incident ray)?
(A) I
(B) II
(C) III
(D) IV
When light travels from a rarer to a denser medium, its speed ______.
How does the speed of light change when it passes from glass to water?
A ray of light is passing from a transparent medium 1 to another transparent medium 2 (i) Speed up (ii) slows down. In each case, state whether the refractive index of medium 2 is equal to, less than or greater than the refractive index of medium 1.
A glass slab is placed over a page on which the word VIBGYOR is printed with each letter in its corresponding colour.
- Will the image of all the letters be in the same place?
- If not, the state which letter will be raised to the maximum. Give a reason for your answer.
Comment on the statement ‘The refractive index of glass is 3/2.’
Light passes through a rectangular glass slab and through a triangular glass prism. In what way does the direction of the two emergent beams differ and why?
The diagram shows the path of a ray of light through a rectangular glass block placed in a liquid of uniform density.

(a) Does the light speed up or slow down in the glass,
(b) Give the reason for your answer.
The path of a ray of light coming from air passing through a rectangular glass slab traced by four students are shown as A, B, C and D in the figure. Which one of them is correct?
![]() |
![]() |
![]() |
![]() |
| A | B | C | D |




