Which instrument is primarily used in military submarines?
Periscope
Periscope is correct.
A periscope lets a submarine crew see objects above the water surface while the vessel stays submerged. It uses two plane mirrors or prisms set at 45° at either end of a long tube, so light is reflected twice and reaches the observer's eye.
A microscope magnifies tiny objects, an endoscope is used to view inside the human body, and a telescope views distant objects directly.
Who was the first one to use a glass prism to obtain the spectrum of sunlight?
Twinkling of stars is due to:
In which a convex mirror is used?
A. Rear View mirrors in vehicles
B. Glass windows
C. Makeup Mirror
D. Kaleidoscope
An object is placed 10 cm in front of a lens. The image formed is real, inverted and of same size as the object. What is the focal length and nature of the lens?
The power of a lens is -2.5 D. The type of lens and its focal length are respectively: