Question

_________ is used in submarine to see objects above the water surfaces
A) Kaleidoscope
B) Periscope
C) MRI
D) None of the above

Answer 1

Hint: Submarines are water crafts designed to function underwater. They need special devices to see the objects above water surfaces. Devices that help to view objects that are not in direct line of sight are used in them. These devices work based on the law of reflection which states that light from an object falls on one mirror at a 45 degree angle from the object and is reflected.

Complete step by step answer:
A special device in the submarine which allows people to see objects above the water surfaces is known as periscope. The word periscope comes from the Greek words Peri which means “around" and Scopus, which means “look." This optical instrument uses prisms, mirrors or lenses to reflect images through a tube. Periscopes are similar to telescopes in structure and working. A long tube with a mirror at each end is the main part of the periscope. The mirrors are attached in parallel to each other at a 45-degree angle. Because of this arrangement, mirrors bounce light reflections between them. i.e., light rays from the object bounce off with the periscope. These light rays enter the periscope and bounce off the top mirror. These rays then hit the mirrors placed at the bottom and bounce into our eyes. Unlike periscopes used in submarines, a simple periscope uses only flat mirrors. Submarines usually use a complex optical system using both mirrors and lenses.

Therefore, the answer is option B.

Note:
Periscopes have many other uses as well. During World War II, periscopes were used to see beyond the tops of trenches. They're also used frequently in armored vehicles to see outside when the vehicle’s openings are shut tight.