A periscope makes use of two -

A. Plane Mirrors

B. Convex Mirrors

C. Concave Mirrors

D. Spherical Mirrors

Solution: A

A periscope is an instrument used to see over, around, or through an object that prevents direct line of sight observation from the observer's position. It makes use of two plane mirrors placed parallel to each other at an angle of 45°. A periscope can be used in submarines, tanks and by soldiers in bunkers to see things outside. 

Hence, option (A) is correct.

Read Class 8 NCERT Notes on Light.

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