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प्रश्न
Explain how spectrum is formed.
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उत्तर
When white light passes through a glass prism, it spreads out into a band of different colours called the spectrum of light.

- When white light is dispersed into seven colours by a glass prism, different colours bend through different angles with respect to the incident ray.
- The sequence of colours given by the prism is Violet, Indigo, Blue, Green, Yellow, Orange and Red.
- Of the seven colours, red light bends the least, while violet light bends the most. So, the rays of each colour emerge along different paths and appear distinct. Hence, we get a spectrum of seven different colours.
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संबंधित प्रश्न
Explain how the formation of a rainbow occurs.
On the basis of the experiment, "To trace the path of a ray of light through a rectangular glass slab", students of a class arrived at which one of the following conclusions?
(A) Angle of incidence is greater than the angle of emergence.
(B) Angle of emergence is smaller than the angle of refraction.
(C) Emergent ray is parallel to the refracted ray.
(D) Incident ray and emergent ray are parallel to each other.
Draw the diagram given below and clearly show the path taken by the emergent ray.

Name a prism required for obtaining a spectrum of Ultraviolet light.
A ray of light passes from glass into air. The angle of refraction will be:
(a) equal to the angle of incidence
(b) greater than the angle of incidence
(c) smaller than the angle of incidence
(d) 45°
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. When is the glass piece not seen?
How does the angle of minimum deviation produces by a prism change with increase in :
the wavelength of incident light
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
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 ?
Draw a ray diagram showing the lateral displacement of a ray of light when it passes through a parallel sided glass slab.
How does the deviation produced by a prism depend on the refraction index of its material.
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.
The refractive index of glass with respect to air is 3/2. What is the refractive index of air with respect to glass?
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.
Which colour of white light travels fastest in any medium except air?
What is lateral displacement?
