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प्रश्न
Show with the help of a diagram how a total reflecting prism can be used to turn a ray of light through 90°. Name one instrument in which such a prism is used.
उत्तर
As shown in the diagram, a beam of light is incident on face AB of the prism normally, so it passes undeviated and strikes face AC, where it makes an angle of 45° with the normal to AC. Because here the incident angle is greater than the critical angle, rays suffer total internal reflection and reflect at an angle of 45°. The beam then strikes face BC, where it is incident normally and so passes undeviated. As a result, the incident beam deviates by 90°. Such a prism is used in periscopes.
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संबंधित प्रश्न
Copy the diagram given below and complete the path of the light ray till it emerges out of the prism. The critical angle of glass is 42°. In your diagram mark the angles wherever necessary.
A ray of light XY passes through a right-angled isosceles prism as shown below
- What is the angle through which the incident ray deviates and emerges out of the prism?
- Name the instrument where this action of the prism is put into use.
- Which prism surface will behave as a mirror?
What is a total reflecting prism?
In the following figure, a ray of light PQ is incident normally on the hypotenuse of an isosceles right angle prism ABC.
- Complete the path of the ray PQ till it emerges from the prism. Mark in the diagram the angle wherever necessary.
- What is the angle of deviation of the ray PQ?
- Name a device in which this action is used.
What device other than a plane mirror can be used to turn a ray of light through 180°? Draw a diagram in support of your answer. Name an instrument in which this device is used.
Mention one difference between reflection of light from a plane mirror and total internal reflection of light from a prism.
In the given figure, a ray of light PQ is incident normally on the face AB of an equilateral glass prism. Complete the ray diagram showing its emergence into air after passing through the prism. Take critical angle for glass = 42°.
- Write the angles of incidence at the faces AB and AC of the prism.
- Name the phenomenon which the ray of light suffers at the face AB, AC and BC of the prism.
A total reflecting equilateral prism can be used to deviate a ray of light through ______.
A total reflecting right angled isosceles prism can be used to deviate a ray of light through ______.
Complete the path of ray PQ through the glass prism ABC shown in Fig. till it emerges out of the prism. Given the critical angle of the glass is 42°.
