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प्रश्न
What is a spectrum?
उत्तर
The band of colored components of a beam of light is called a spectrum.
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संबंधित प्रश्न
When rays of light are incident on a glass slab then the incident ray and emergent ray are _________ each other.
- perpendicular
- parallel
- opposite
- concurrent
After tracing the path of a ray of light passing through a rectangular glass slab for four different values of the angle of incidence, a student reported his observations in tabular form as given below:
| S.No | ∠ i | ∠ r | ∠ e |
| I | 30° | 19° | 29° |
| II | 40° | 28° | 40° |
| III | 50° | 36° | 50° |
| IV | 60° | 40° | 59° |
The best observation is
(A) I
(B) II
(C) III
(D) IV
Draw a ray diagram to show the refraction of light through a glass slab and mark angle of refraction and the lateral shift suffered by the ray of light while passing through the slab.
A student very cautiously traces the path of a ray through a glass slab for different values of the angle of incidence (∠i). He then measures the corresponding values of the angle of refraction (∠r) and the angle of emergence (∠e) for every value of the angle of incidence. On analysing these measurements of angles, his conclusion would be
(A) ∠i > ∠r > ∠e
(B) ∠i = ∠e > ∠r
(C) ∠i < ∠r < ∠e
(D) ∠i = ∠e < ∠r
Explain the term absolute refractive index of a medium and write an expression to relate it with the speed of light in vacuum.
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?
Write the relation between the angle of incidence and the angle of refraction for a medium.
A monochromatic ray of light passes from air to glass. The wavelength of light in air is λ, the speed of light in air is c and in glass is V. If the absolute refractive index of glass is 1.5, write down
- the relationship between c and V,
- the wavelength of light in glass.
How does the angle of minimum deviation produces by a prism change with increase in :
the wavelength of incident 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.
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?
Select from the following the best set-up for tracing the path of a ray of light through a rectangular glass slab:
(A) I
(B) II
(C) III
(D) IV
While tracing the path of a ray of light passing through a rectangular glass slab a student tabulated his observations as given below:
|
S.NO. |
∠i |
∠r |
∠e |
|
I |
60° |
40° |
61° |
|
II |
50° |
36° |
51° |
|
III |
40° |
28° |
39° |
|
IV |
30° |
20° |
31° |
The correct observations is:
(A) I
(B) II
(C) III
(D) 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)` .
Fig shows a lens as a combination of a glass block and two prisms.
(i) Name the lens formed by the combination.
(ii) what is the XX' called?
(iii) Complete the ray diagram and show the path of the incident ray PQ after passing through the lens.
(iv) The final emergent ray will either meet XX' at a point or appear to come from a point on XX'. what is the point called?
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 ?
Name the phenomenon responsible in the following case:
Apparent bending of a stick in water
Why upper surface of water contained in a beaker and above eye level appears silvery?
Express the refractive index μ of a medium in terms of the velocity of light.
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.
How does the angle of deviation produced by a prism depend on the angle of incidence of light at the prism surface? Draw a graph to illustrate your answer.
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?
A ray of monochromatic light is incident from the air on a glass slab:
(i) Draw a labelled ray diagram showing the change in the path of the ray till it emerges from the glass slab.
(ii) Name the two rays that are parallel to each other.
(iii) Mark the lateral displacement in your diagram.
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.
A ray of light PQ is incident normally on the hypotenuse of a right-angled prism ABC as shown in the diagram given below:
(i) Copy the diagram and complete the path of the ray PQ till it emerges from the prism.
(ii) What is the value of the angle of deviation of the ray?
(iii) Name an instrument where this action of the prism is used.
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?
Observe the figure and name the ray AB, ray CD, ray GH.
Which colour of white light travels fastest in any medium except air?
