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Questions
What is total internal reflection?
Explain total internal reflection of light.
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Solution
Total internal reflection is the phenomenon when a ray of light travelling in a denser medium is incident at the surface of a rarer medium such that the angle of incidence is greater than the critical angle for the pair of media, and the ray is totally reflected back into the denser medium.
RELATED QUESTIONS
In the given figure PQ and PR are the two light rays emerging from an object P. The ray PQ is refracted as QS.
- State the special name given to the angle of incidence ∠PQN of the ray PQ.
- What is the angle of refraction for the refracted ray QS?
- Name the phenomenon that occurs if the angle of incidence ∠PQN is increased.
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- Draw in the diagram the refracted ray for the incident ray PR and hence show the position of image of the object P by the letter P’ when seen vertically from above.
i) Observe the given figure and answer the following questions.
a) Identify and write the natural process shown in the figure.
b) List the phenomena which are observe in this process.
c) Redraw the diagram and show above phenomena in it.

Total internal reflection can take place only if ______.
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(i) Define critical angle.
(ii) State one important factor which affects the critical angle of a given medium.
Plot a graph between
Angle of incidence versus angle of refraction.
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The adjacent diagram shows two right-angled isosceles prisms A and B. Complete the diagram to show the path of rays P and Q emerging out of the prism B. What principles have you used to complete the diagram?

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Answer the following question.
Define the critical angle of incidence and obtain an expression for it.
Answer the following question.
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The outer concentric shell in optic fiber is called ______.
A bundle of glass threads, each of which is capable of transmitting messages using light waves is called ______.
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- Label A and B of the given diagram. Why colour will deviate most.
- Name the phenomenon shown in label C.
Find the value of θ in the given figure.

