Advertisements
Advertisements
प्रश्न
Describe the principle of simple periscope through an outline ray diagram. Give one of its uses.
Advertisements
उत्तर
Simple periscope is based upon the principle of reflection. It consists of cardboard or wooden tube, bent twice at right angles, and is provided with two openings as shown in the figure. Two plane mirrors are fixed at the bends of the tube at an angle 45° to the framework, such that the mirrors face each other. The tube is completely blackened from inside to avoid any reflection from its sides.
The parallel rays coming from an object at a higher plane, strike the plane mirror at an angle of 45° and hence are reflected through an angle of 45°.
These reflected rays strike the second mirror at an angle of 45° and hence are further reflected through an angle of 45°. These reflected rays on reaching the eye from the image on retina.
Use of periscope: It is used by soldiers in trench warfare.
APPEARS IN
संबंधित प्रश्न
Write true or false of the following statement.
The image formed by a plane mirror can be obtained on a screen.
What is meant by lateral inversion of an image in a plane mirror ? Explain it with the help of a diagram.
State two uses of a plane mirror.
How will you explain the statement 'we cannot see the objects in a dark room'?
State three ways in which the image formed in a plane mirror differs from the image formed in a pin hole camera.
You are provided a convex mirror, a concave mirror and a plane mirror. How will you distinguish between them, without touching or using any other apparatus?
State whether the following statement is true or false. If false, correct it.
If the incident ray makes an angle of Xo with the normal, then the reflected ray is 2Xo.
Complete the ray diagram to show the image observed by the eye after reflection in the following figure.
Why does a light ray incident on a rectangular glass slab immersed in any medium emerges parallel to itself? Explain using a diagram.
A burning candle in water
Take a shoe box, open on one side. Place a small lighted candle in it. Place a clear glass sheet (roughly 25 cm × 25 cm) in front of this candle figure. Try to locate the image of the candle behind the glass sheet. Place a glass of water at its position. Ask your friends to look at the image of the candle through the sheet of glass. Ensure that candle is not visible to your friends. Your friends will be surprised to see the candle burning in water. Try to explain the reason.
