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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
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?
How does the speed of light change when it passes from glass to water?
Complete Fig. 4.32 to show the path of the ray of single colour as it enters the prism and emerges out of it. Mark the angles wherever necessary.
Four students showed the following traces of the path of a ray of light passing through a rectangular glass slab.
The trace most likely to be correct is that of student
(A) I
(B) II
(C) III
(D) IV
How does the deviation produced by a prism depend on the refraction index of its material.
Write a relation between the angle of incidence (i), angle of emergence (e), angle of the prism (A), and angle of deviation (d) for a ray of light passing through an equilateral prism.
Draw ray of light bending towards the normal while passing from air to glass. Label your diagrams.
Calculate the velocity of light in a glass block of refractive index 1.5. (Velocity of light in air = 3 × 108 m/s)
The speed of light in air is 3 × 108 ms-1. Calculate the speed of light in water. The refractive index of water is 4/3.
Draw the ray diagram of a glass slab having medium A and B for the velocity of light ray VA and VB respectively and define Snell's law.
- If VB = 1.5 VA, then which medium is denser?
- What is the refractive index of A with respect to B?
- What is the refractive index of B with respect to A?
