Question

An optical instrument used to observe small organisms is called _________________.
A. Microscope
B. Telescope
C. Magnifying lens
D. Both A and B

Answer 1

Hint: An optical instrument is a device that uses light to enhance the image for a more clear view. This instrument usually makes an object bigger and helps us to see the object in a more detailed manner.

Complete answer:
The small organisms are the tiny living organisms. They can be determined according to organism size; it may be in terms of genome size, volume, mass, length and height. They are usually single-cell organisms. They are very small in size and not visible to the naked eye. To examine them, it required a special type of instrument called a microscope. The image formed by an object is magnified through at least one lens in the microscope. The lens bends the light towards the eyes and makes the object appear clear and bigger. It helps us to study the structure and other details. The microscope is generally used to study the small organisms which are not visible through naked eyes but it also helps to study other objects like study of hair, cheeks cells, etc.
A telescope is used to see distant objects like stars. It is also an optical instrument. It has lenses, curved mirrors or can be a combination of both. It covers a wide variety of instruments. Other various devices used their emission, absorption or reflection of electromagnetic radiation to observe the distant objects.
A magnifying lens is also a hand lens using a convex lens to produce a magnified image of an object. It is generally used by the jewellery or used to magnify the writing sample, etc. the magnification depending upon where it is placed that is between the viewer’s eyes and the object and the total distance between them.

Therefore the correct answer is option A that is a microscope.

Note: All these three are the optical instrument, but all of them are used to observe different things. The converging lens (convex lens) always produced a bigger image where the diverging lens (concave lens) produces a smaller image. The periscope and cameras are also the most common examples of the optical instrument.