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प्रश्न
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उत्तर
Two advantages of using total reflecting prism as a reflector in place of a plane mirror are:
(i) When total internal reflection occurs, the entire light (100%) is reflected back into the denser medium, whereas in ordinary reflection from plane mirror, some light is refracted or absorbed (i.e. reflection is partial).
(ii) Total reflecting prism gives a much brighter image than that obtained by using the plane mirror.
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संबंधित प्रश्न
Why do we get a spectrum of seven colors when white light is dispersed by a prism?
How is the refractive index of a medium related to the speed of light in it?
In the adjacent diagram, AO is a ray of light incident on a rectangular glass slab.

- Complete the path of the ray till it emerges out of the slab.
- In the diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to the angles i and r?
- Mark angles of emergence by the letter e. How are the angles i and e related?
- Which two rays are parallel to each other? Name them.
- Indicate in the diagram the lateral displacement between the emergent ray and the incident ray. State one factor that affects the lateral displacement.
When light travels from a rarer to a denser medium, its speed ______.
(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)` .
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.
A ray of light passes from water to air. How does the speed of light change?
The diagram shows the path of a ray of light through a rectangular glass block placed in a liquid of uniform density.

(a) Does the light speed up or slow down in the glass,
(b) Give the reason for your answer.
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.
