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प्रश्न
A light ray in passing from water to a medium
(a) speeds up
(b) slows down. In each case, give one example of the medium.
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उत्तर
When the speed increases it means that the refractive index of the medium is less than that of water.
When the speed decreases it means that the refractive index of the medium is greater than that of water.
संबंधित प्रश्न
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
Explain the term absolute refractive index of a medium and write an expression to relate it with the speed of light in vacuum.
Observe the following figure and answer the questions given under it:
1) How many times does refraction take place in the above figure?
2) What happens to the ray of light when it passes from air to glass?
3) What happens to the ray of light when it passes from glass to air?
4) What are the rays AB and CD in the figure called?
5) Define refraction.
What do you understand by the statement the refractive index of glass is 1.5 for white light?
The diagram alongside shows the refraction of a ray of light from air to a liquid.
- Write the values of (i) angle of incidence, (ii) angle of refraction.
- Use Snell’s law to find the refractive index of liquid with respect to air.
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
What is the total reflecting prism?
Draw a diagram to show the refraction of a monochromatic light ray through an equilateral prism. On the diagram, label the incident, refracted, and emergent rays. It also indicates the angle of deviation by the letter δ.
In the diagram alongside a ray of light, PQ is incident normally on one face AB of an equilateral glass prism. What is the angle of incidence at the faces AB and AC?
Which colour of white light travels fastest in any medium except air?
