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प्रश्न
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.
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उत्तर
An expression for heat produced in a conductor by using Joule's experiment:
1) Refraction occurs twice, once at Point N and the second time at Point M.
2) Air is rarer than glass. So, when light passes from the rarer medium to the denser medium, it bends towards the normal.
3) When light passes from the denser (glass) medium to the rarer (air) medium, it bends away from the normal.
4) Ray AB is called the incident ray, and ray CD is called the emergent ray.
5) Refraction of light is the phenomenon of change in the direction of propagation of light when it passes obliquely from one transparent medium to another.
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संबंधित प्रश्न
A student traces the path of a ray of light passing through a rectangular glass slab and marks the angle of incidence i, angle of refraction r and angle of emergence e, as shown.
The correctly marked angle(s) is/are
(A) ∠ i only
(B) ∠ e only
(C) ∠ r only
(D) ∠ i and ∠ e
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
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.
A ray of light strikes the surface of a rectangular glass block such that the angle of incidence in
air is 0°.
In each case, draw diagram to show the path taken by the ray as it passes through the glass block and emerges from it.
When a ray of light from air enters a denser medium, it ______.
With the help of diagram of the principal section of a prism, indicate its refracting surfaces, refracting edge and base.
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.
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.
Name the colour of white light which is deviated the most on passing through a prism.
A postage stamp kept below a rectangular glass block of refractive index 1.5 when viewed from vertically above it, appears to be raised by 7.0 mm. Calculate the thickness of the glass slab.
A ray of light OP passes through a right angles prism as shown in the adjacent diagram.
(a) State the angles of incidence at the faces AC and BC.
(b) Name the phenomenon which the ray suffers at the face AC.
Select from the following the best experimental set-up for tracing the path of a ray of light through a glass slab:
(A) I
(B) II
(C) III
(D) IV
Which of the following is the best experimental set-up out of the four shown for tracing the path of a ray of light passing through a rectangular glass slab ?
While performing the experiment on tracing the path of a ray of light through a rectangular glass slab, in which of the following experimental set-ups is a student likely to get best results? P1 and P2 are the positions of pins fixed by him.
(A) I
(B) II
(C) III
(D) IV
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
(i) What is the relation between the refractive index of water with respect to air `("_aμ_\text(w))` and the refractive index of air with respect to water `("_\text(w)μ_ a)` .
(ii) If the refractive index of water with respect to air `("_aμ_\text(w))` is`5/3`. Calculate the refractive index of air with respect to water `("_\text(w)μ_ a)` .
Fill in the blank to complete the following sentence:
When light travels from a rarer to a denser medium, it bends ...........
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.
Which colour of light travels fastest in any medium except air?
How does the deviation produced by a prism depend on the refraction index of its material.
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 __________________.
Name the phenomenon responsible in the following case:
Twinkling of stars
Why does a fisherman aim at the tail of fish during spearfishing?
What is the refractive index of vacuum
Comment on the statement ‘The refractive index of glass is 3/2.’
Express the refractive index μ of a medium in terms of the velocity of light.
What is the total reflecting prism?
In what condition a prism is said to be in the position of minimum deviation? What is the direction of the refracted ray inside the prism in this condition?
The refractive index of air with respect to glass is defined: as gµa = sin i/sin r
Write down a similar expression for aµg in terms of angle i and r.
The refractive index of air with respect to glass is defined: as gµa = sin i/sin r
If r = 90°, what is the corresponding angle i called?
After a robbery, if a window has been broken, there will be tiny particles of glass. Some of these will be found at the scene of the crime and some may be caught in the thief’s clothing. If the police can prove that these particles are identical, they have a strong case.
A method of doing this is to suspend the particles of glass in a special liquid. Light of a single colour is thrown through the liquid and the particles viewed through a microscope. The temperature of the liquid is then slowly altered. This alters the speed of light through the liquid (i.e., it alters the refractive index). At one particular temperature, the particles of glass disappear. It this happens at the same temperature for both sets of glass particles, they probably came from the same broken pane of glass.
Complete and copy the diagram to show how light bends when it travels from the liquid to the glass and back to the liquid, If the light slows down in the glass.
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.
Two parallel rays of Red and Violet travelling through the air, meet the air-glass boundary as shown in the above figure. Will their paths inside the glass be parallel? Give a reason for your answer.
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?
A glass block is having refractive index 3/2, the light ray is incident at an angle 45°. Find the sine of the angle of, refraction inside the glass block.
The path of a ray of light coming from air passing through a rectangular glass slab traced by four students are shown as A, B, C and D in the figure. Which one of them is correct?
 |
 |
 |
 |
| A | B | C | D |
