Question

What is a periscope? How many mirrors are there in a periscope?

Answer 1

A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with mirrors at each end set parallel to each other at a ${45}^{\circ }$ angle. There are two mirrors in a simple periscope.