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प्रश्न
Explain with the help of a diagram of how fish is able to see the objects above it.
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उत्तर
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.
संबंधित प्रश्न
When rays of light are incident on a glass slab then the incident ray and emergent ray are _________ each other.
- perpendicular
- parallel
- opposite
- concurrent
Four students P, Q, R and S traced the path of a ray of light passing through a glass slab for an angle of incidence 40° and measured the angle of refraction. The values as measured them were 18°; 22°; 25° and 30° respectively. The student who has performed the experiment methodically is
(A) P
(B) Q
(C) R
(D) S
A ray of light passes from glass into air. The angle of refraction will be:
(a) equal to the angle of incidence
(b) greater than the angle of incidence
(c) smaller than the angle of incidence
(d) 45°
How does the angle of minimum deviation produces by a prism change with increase in :
the wavelength of incident light
How does the angle of minimum deviation produces by a prism change with increase in :
the refracting angle of prism?
Rahim recorded the following sets of observations while tracing the path of a ray of light passing through a rectangular glass slab for different angles of incidence.
|
S. No. |
Angle of incidence |
Angle of refraction |
Angle of emergence |
|
I |
45° |
41° |
45° |
|
II |
40° |
38° |
38° |
|
III |
45° |
41° |
40° |
|
IV |
41° |
45° |
41° |
The correct observation is recorded at serial number:
(1) I
(2) II
(3) III
(4) IV
A ray of light passes from air to water. In fig. 39, which of the ray A, B, C and D is the correct refracted ray?
Draw a diagram to show the splitting of white light into its constituent colours.
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 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.
