Advertisements
Advertisements
Question
Describe the principle of simple periscope through an outline ray diagram. Give one of its uses.
Advertisements
Solution
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
RELATED QUESTIONS
State two uses of a plane mirror.
Explain the differences between regular and irregular reflection light.
In the figure is shown a concave mirror. A is a point on the principal axis. If an object O is kept at A, image is formed on A itself. Copy the diagram. Draw the image in the diagram. Is the image real or virtual?
Measure the distance PA and write it in the diagram. What is the distance PA called?
Mark a point B on the principal axis, at which, if a point source of light is kept, the rays travel parallel to principal axis after reflection from M. What is point B called?
Which of the following is the best reflector of light?
A ray of light is travelling in a direction perpendicular to the boundary of a parallel glass slab. The ray of light ______.
Which material is transparent?
Plane mirrors are used as looking glass, to reflect light on objects and in periscopes.
We can see objects because of ______.
