Explain the working of a periscope.

Light reflected from an object enables us to see the object when it is in the line of sight. Periscopes have long been used in order to see the objects that are not in direct line of sight. Periscopes are optical devices that use the laws of reflection.

A simple periscope uses two mirrors inclined at an angle of 45 degrees as shown in the figure. When light falls on one mirror, it is reflected back and falls on the other mirror and gets reflected to the observer’s eyes. It helps to view over, around or through an object.