Question

What is periscope? And how does reflections help in submarines. How are submarine useful for every country’s security?

Answer 1

Periscopes can be used in many ways beyond seeing above water from a submarine. ...

The main part of a periscope is a long tube that has a mirror at each end. The mirrors are attached so that they are parallel to each other at a 45-degree angle. Arranged in this way, the mirrors bounce reflections of light between them.