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Question
How are critical angles related to the refractive index of the medium?
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Solution
RELATED QUESTIONS
The diagram below shows a point source P inside a water container. Four rays A, B, C, D starting from the source P, are shown up to the water surface.
- Show in the diagram the path of these rays after striking the water surface. The Critical Angle for the water-air surface is 48°.
- Name the phenomenon which the rays B and D exhibit.
What do you understand by the deviation produced by a prism? Why is it caused?
Write the relation between the refractive index and critical angle for a given pair of optical media?
One day Chetan’s mother developed a severe stomach ache all of a sudden. She was rushed to the doctor who suggested for an immediate endoscopy test and gave an estimate of expenditure for the same. Chetan immediately contacted his class teacher and shared the information with her. The class teacher arranged for the money and rushed to the hospital. On realizing that Chetan belonged to a below average income group family, even the doctor offered concession for the test fee. The test was conducted successfully.
Answer the following questions based on the above information:
(a) Which principle in optics is made use of in endoscopy?
(b) Briefly explain the values reflected in the action taken by the teacher.
(c) In what way do you appreciate the response of the doctor on the given situation?
The observation made by Swarali while doing the experiment is given below. Based on these write answers to the questions:
Swarali found that the light ray travelling from the denser medium to rarer medium goes away from the normal. If the angle of incidence (i) is raised by Swarali, the angle of refraction (r) went on increasing. However, after certain value of the angle of incidence the light ray is seen to return back into the denser medium.
Questions:
- What is the specific value of∠i called?
- What is the process of reflection of incident rays into denser medium called?
- Draw the diagrams of three observations made by Swarali.
Make the correct choices for each of the following :
Total Internal reflection takes place when
(where ∠i = angle of incidence, ∠r = angle of refraction, ∠C = critical angle)
A ray of light passes through a right-angled prism as shown in the figure. State the angles of incidence at the faces AC and BC.
PQ and PR are two light rays emerging from the object as shown in the figure below:
(i) What is the special name given to the angle of incidence (∠PQN) of ray PQ?
(ii) Copy the ray diagram and complete it to show the position of the image of the object P when seen obliquely from above.
(iii) Name the phenomenon that occurs if the angle of incidence ∠PQN is increased still further.
Optical fibre communication uses the principle of ______.
Optical Fibres are based on the phenomenon of dispersion.
