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Question
Explain with the help of a diagram of how fish is able to see the objects above it.
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Solution
A fish can see everything above it in clear water irrespective of its position in different depths. The critical angle for water is 48.5°. The angle of the cone of vision for the fish is twice this angle.
Hence it is 97°. All the objects outside water but in this cone of vision Will be seen by the fish. Outside this range, the fish will see all the objects in the surrounding area (see figure). Those objects which are at the bottom will be seen by the fish due to total internal reflection taking place at the water-air interface.
RELATED QUESTIONS
Draw the diagram of refraction of light in the glass slab
What do you understand by the statement the refractive index of glass is 1.5 for white light?
Name the colour of white light which is deviated the most on passing through a prism.
Trace the path of a ray of light incident at an angle of 45° on a rectangular glass slab. Write the measure of the angle of refraction, the angle of emergence and the lateral displacement suffered by the ray as it passes through the slab.
After tracing the path of rays of light through a glass slab for three different angles of incidence, a student measured the corresponding values angle of refraction r and angle of emergence e and recorded them in the table given below:
|
S. No. |
∠i |
∠i |
∠e |
|
I |
30° |
20° |
31° |
|
II |
40° |
25° |
40° |
|
III |
50° |
31° |
49° |
The correct observations are:
(A) I and II
(B) II and III
(C) I and III
(D) I, II and III
Which of the following has the highest refractive index:
Light of a single colour is passed through a liquid having a piece of glass suspended in it. On changing the temperature of liquid, at a particular temperature, the glass piece is not seen.
Why is the light of a single colour used ?
The diagram below shows two parallel rays A (Orange) & B (Blue) incident from air, on air-glass boundary.
- Copy and complete the path of the rays A and B.
- How do the speeds of these rays differ in glass?
- Are the two refracted rays in glass parallel? Give a reason.
