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प्रश्न
Explain the working of a periscope.
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उत्तर
Periscope:
- It is an instrument used for viewing bodies or ships, which are over and around another body or a submarine.
- It is based on the principle of the law of reflection of light.
- It consists of a long outer case and inside this case mirrors or prisms are kept at each end, inclined at an angle of 45°.
- Light coming from the distant body falls on the mirror at the top end of the periscope and gets reflected vertically downward.
- This light is reflected again by the second mirror kept at the bottom, so as to travel horizontally and reach the eye of the observer.
- In some complex periscopes, optic fiber is used instead of mirrors for obtaining a higher resolution.
- The distance between the mirrors also varies depending on the purpose of using
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संबंधित प्रश्न
Define the following terms used in the study of reflection of light by drawing a labelled ray-diagram:
- Incident ray
- Point of incidence
- Normal
- Reflected ray
- Angle of incidence
- Angle of reflection
Why does a ray of light bend when it travels from one medium to another?
What is meant by ‘refraction of light’?
Water is optically .......... than air.
When a ray of light travels from air to glass, it bends .......... the normal.
Match the Following
| Column A | Column B |
| (a) white Light | (1) Convex mirror |
| (b) Refraction | (2) Concave mirror |
| (c) Virtual images | (3) refraction |
| (d) Real images | (4) spectrum |
| (e) Prism | (5) ray of light from glass to air |
Fill in the blank and Explain the completed sentences.
The change in ______ of light rays while going from one medium to another is called refraction.
Which object use the reflection of light?
The phenomenon of light passing through the object is called ______.
A ray of light traveling in medium 1 strikes and travels into another transparent medium 2. If the speed of light is greater in medium 1, the ray will ______.
