11.8.1 Periscope

Last updated at June 19, 2026 by

๐Ÿ’ฌ Think about it

How does a soldier inside a tank see what is outside? Or how can you peek over a tall crowd? Two mirrors in a Z-shaped box can do this trick. Let us see how a periscope works.

How does a periscope work?
  • A periscope uses two plane mirrors in a Z-shaped box.
  • Light reflects from one mirror to the other.
  • This lets us see objects not visible directly.
  • Periscopes are used in submarines, tanks, and bunkers.
Example: You can use a periscope to look ahead when standing behind taller friends.
Important Points
  • A periscope uses two plane mirrors.
  • It lets us see objects that are hidden from direct view.
Important Definitions
  • Periscope — a device with two plane mirrors that lets us see objects not visible directly.

๐Ÿ“‹ NCERT Question 11 — Suppose you are given

Suppose you are given a tube of the shape shown in Fig. 11.20 and two plane mirrors. Can this tube be used to make a periscope?
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