Advertisements
Advertisements
प्रश्न
Choose the correct alternative and rewrite the following sentence.
A ray of light strikes the glass slab at an angle of 50°. What is the angle of incidence?
पर्याय
50°
90°
60°
40°
Advertisements
उत्तर
40°
The ray of light strikes at an angle of 50 with the horizontal. The angle of incidence is with respect to the normal, so the angle of incidence is 90° − 50° = 40°.
APPEARS IN
संबंधित प्रश्न
When a ray of light travels from air to glass slab and strikes the surface of separation at 90°, then it …………….
(a) bends towards normal
(b) bends away from normal
(c) passes unbent
(d) passes in zigzag way
What is a spectrum?
If the speed of light in vacuum is 3 × 108 ms−1, find the speed of light in a medium of absolute refractive index 1.5.
State the dependence of angle of deviation On the refractive index of the material of the prism.
The speed of light in glass is 2 × 105 km/s. What is the refractive index of glass?
A ray of light passes from water to air. How does the speed of light change?
Name a prism required for obtaining a spectrum of Ultraviolet light.
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.
When a lighted candle is held in front of a thick plane glass mirror, several images can be seen, but the second image is the brightest, give reason.
How does the angle of deviation produced by a prism change with increase in the angle of incidence. Draw a curve showing the variation in the angle of deviation with the angle of incidence at a prism surface.
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.
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.
What do you understand by the statement the refractive index of glass is 1.5 for white light?
In fig 4.18, name the ray which represents the correct path of light while emerging out through a glass block.
A Water pond appears to be 2.7 m deep. If the refractive index of water is 4/3, find the actual depth of the pond.
The critical angle for glass-air is 45° for the light of yellow colour. State whether it will be less than, equal to, or more than 45° for (i) ref light, (ii) blue light?
The refractive index of air with respect to glass is expressed as `""_g μ_a=sin i /sin r`.
- Write down a similar expression for aμg in terms of the angles i and r.
- If angle r = 90°, what is the corresponding angle i called?
- What is the physical significance of the angle i in part (b)?
The refractive index of glass is 1.5. From a point P inside a glass block, draw rays PA, PB and PC incident on the glass air surface at an angle of incidence 30°, 42° and 60° respectively.
- In the diagram show the approximate direction of these rays as they emerge out of the block.
- What is the angle of refraction for the ray PB?
`("Take" sin 42° =2/3)`
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
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
Which of the following has the highest refractive index:
Draw an í- `delta` graph for a mono chromatic raY through a glass prism of a plane and mark
(i) `delta` m, the angle of mínimum devíation
(íí) Any two values of i for which value of `delta` ís same.
In an experiment of finding the refractive index of glass, if blue light is replaced by the red light, how will the refractive index of glass change? Give reason in support of your answer.
Which colour of light travels fastest in any medium except air?
Rewrite the following statement by selecting the correct option:
If a ray of light strikes a glass slab at an angle of 600 with the surface of the slab, the angle of incidence must be __________________.
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.
What is the refractive index of vacuum
What should be the ratio of the speed of light through the liquid to the speed through the glass so that there is no refraction of light at the boundaries of the glass block when the system is illuminated by the light of one colour?
Comment on the statement ‘The refractive index of glass is 3/2.’
What is the total reflecting prism?
A ray of light moves from a rare medium to a dense medium as shown in the diagram below. Write down the number of the ray which represents the partially reflected ray.
The diagram shows the path of a ray of light through a rectangular glass block placed in a liquid of uniform density.
What should be the rate of the speed of light through the liquid to the speed through the glass so that there is no refraction of light at the boundaries of the glass block when the system is illuminated by the light of one colour?
Draw a diagram of a prism and label:
(i) the base,
(ii) the refracting surfaces,
(iii) the refracting edge,
(iv) the refracting angle in it.
A coin placed at the bottom of a beaker appears to be raised by 4.0 cm. If the refractive index of water is 4/3, find the depth of the water in the beaker.
