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प्रश्न
Choose the correct alternative and rewrite the following:
A glass slab is placed in the path of convergent light. The point of convergence of light
पर्याय
moves away from the slab
moves towards the slab
remains at the same point
undergoes lateral shift
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उत्तर
moves away from the slab
If the glass slab is placed in the path of convergent light, the point of convergence or focus will shift away from the glass slab as the light passing through glass will bend towards the normal and after coming out in the air, the light will converge out at a point away from the glass slab.
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संबंधित प्रश्न
In your laboratory you trace the path of light rays through a glass slab for different values of angle of incidence (∠i) and in each case measure the values of the corresponding angle of refraction (∠r) and angle of emergence (∠e). On the basis of your observations your correct conclusion is:
(a) ∠i is more than ∠r, but nearly equal to ∠e
(b) ∠i is less then ∠r, but nearly equal to ∠e
(c) ∠i is more than ∠e, but nearly equal to ∠r
(d) ∠i is less than ∠e, but nearly equal to ∠r
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.
How can you bend light away from the normal?
A ray of light of wavelength 6600 Å suffer refraction from air to glass. Taking \[\ce{_a\mu_g = \frac{3}{2}}\], find the wavelength of light in glass.
How does the angle of minimum deviation produces by a prism change with increase in :
the refracting angle of prism?
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.
How does the speed of light change when it passes from glass to water?
What do you understand by the statement the refractive index of glass is 1.5 for white light?
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.
Trace the path of a ray of light incident at an angle of 45° on a rectangular glass slab. Write the measure of the angle of refraction, the angle of emergence and the lateral displacement suffered by the ray as it passes through the slab.
A ray of light falls normally on the surface of a transparent glass slab. Draw a ray diagram to show its path and also mark angle of incidence and angle of emergence.
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
Define the term refractive index of a medium. What do you understand by the statement 'the refractive index of glass is 1.5 for white light'?
Fill in the blank to complete the following sentence:
When light travels from a rarer to a denser medium, it bends ...........
Make the correct for each of the following :
With reference to the fig, the refractive index of the glass block is

Light of a single colour is passed through a liquid having a piece of glass suspended in it. On changing the temperature of liquid, at a particular temperature, the glass piece is not seen.
Why is the light of a single colour used ?
How does the deviation produced by a prism depend on the wavelength of incident light?
Which colour of light travels fastest in any medium except air?
Why is the colour red used as a sign of danger?
Name one main factor on which the direction of bending of a ray of light depends.
During sunset and sunrise, the sun is seen when it is slightly below the horizon. Give reason.
State the factors on which the angle of deviation depends.
Name the material for which the refractive index is found to be maximum.
Express the refractive index μ of a medium in terms of the velocity of light.
How does the angle of deviation produced by a prism depend on the colour of light used? Which colour of white light is deviated (i) most, (ii) least, by a prism?
In the diagram below, PQ is a ray of light incident on a rectangular glass block.

How are the angles ‘i’ and ‘e’ related to each other?
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?

How will you verify the laws of refraction or how the refractive index of glass is determined in the laboratory?
The diagram shows the path of a ray of light through a rectangular glass block placed in a liquid of uniform density.

Show with the help of a ray diagram the path of the ray when incident ray normally falls on the first surface of the glass block and passes through the block and the liquid.
Trace a ray of light incident at 30° on a surface if travelling from glass to air. What is the angle of refraction in this case? (R.I. for glass = 3/2).
Write the approximate values of speed of light in (i) air and (ii) glass. Use these values to calculate the refractive index of glass with respect to air.
The refractive index of glass with respect to air is 1.5. What is the value of the refractive index of air with respect to glass?
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.
