MCQ on Microscopy with Answers: 

• A microscope is an instrument that can be used to observe small objects, even cells that are too small to be seen by the naked eye.
• It is mainly used to amplify tiny objects into instruments that can be seen by the naked eye.
• The ability of a microscope to distinguish two adjacent points as distinct and separate is known as resolving power. Resolving power is a function of the wavelength of light used and the numerical aperture (NA) of the lens system.
• A compound microscope contains three separate lens systems. The condenser lens is placed between the light source and the specimen and it gathers and focuses the light rays in the plane of the microscopic field to view the specimen.
• The image formed by an objective of a compound microscope is real and enlarged. 
• The electron microscope is the most powerful.
• The principle of an electron microscope is the same as that of an optical microscope, except that the electrons have shorter wavelengths and can see smaller objects.

Microscope MCQ Questions with Answers: 

1. What is a microscope?

(1) A microscope is an instrument that can be used to observe small objects, even cells.

(2) A microscope is a laboratory instrument used to examine objects that are too small to be seen by the naked eye.

(3) Both of these

(4) None of these

Answer: 3

2. Which microscope is more powerful?

(1) Electron microscope

(2) Compound Microscope

(3) Light Microscope

(4) Simple Microscope

Answer: 1

3. What is the function of the diaphragm in a microscope?

(1) Diaphragm controls the angle of the light cone reaching the specimen.

(2) Controls only the width of the bundle of light rays reaching the condenser.

(3) Both of these

(4) None of these

Answer: 3

4. The human eye’s unaided resolving power is_______

(1) 1 cm

(2) 100um

(3) 200 nm

(4) 400 nm

Answer: 2

5. The image formed by an objective of a compound microscope is

(1) Virtual and enlarged

(2) Virtual and diminished

(3) Real and diminished

(4) Real and enlarged

Answer: 4

6. Who was the first to describe “cells” in dead cork tissue?

(1) Hans Janssen

(2) Zaccharias Janssen

(2) Antonie van Leeuwenhoek

(2) Robert Hooke

Answer: 4

7. To view live cells, which of the following is used?

(1) SEM

(2) TEM

(3) Phase contrast microscope

(4) All of these

Answer: 3

8. In light microscopy, which of the following is used as fixatives before the staining technique?

(1) Osmic acid

(2) Glutaraldehyde

(3) Heat

(4) Osmic acid, glutaraldehyde, heat

Answer: 3

9. What is the resolution of a simple microscope?

(1) The simple microscope has a resolution of 10.

(2) The simple microscope has a resolution of 100

(3) The simple microscope has a resolution of 1000

(4) None of these

Answer: 1

10. Electron Microscope can give a magnification up to ___________

(1) 400,000X

(2) 100,000X

(3) 15000X

(4) 100X

Answer: 1

11. The refractive index of air is_______

(1) 0.50

(2) 0.75

(3) 1.00

(4) 1.25

Answer: 3

12. What is one difference between specimen preparation for a transmission electron microscope (TEM) and preparation for a scanning electron microscope (SEM)?

(1) Only the TEM specimen requires sputter coating.

(2) Only the SEM specimen requires sputter-coating.

(3) Only the TEM specimen must be dehydrated.

(4) Only the SEM specimen must be dehydrated.

Answer: 2

13. What is the focal length of a compound microscope?

(1) 0.95 cm and 5 cm

(2) 95 cm and 5 cm

(3) 0.9 cm and 0.5 cm

(4) None of these

Answer: 1

14. The equipment that is used to make clear magnified sketches of objects under a microscope is called?

(1) Compound microscope

(2) Light microscope

(3) Camera Lucida

(4) Camera attached stereomicroscope

Answer: 3

15. Which of the following is used in an electron microscope?

(1) electron beams

(2) magnetic fields

(3) light waves

(4) electron beams and magnetic fields

Answer: 4

16. Differentiation capacity of a compound microscope is________

(1) 27.5 μm

(2) 2.75 μm

(3) 0.275 μm

(4) None

Answer: 3

17. Resolving power of light microscope is________

(1) 2 mm

(2) 0.2 mm

(3) 0.1 mm

(4) 1 mm

Answer: 2

18. Which part of the compound microscope helps in gathering and focusing light rays on the specimen to be viewed?

(1) Eyepiece lens

(2) Objective lens

(3) Condenser lens

(4) Magnifying lens

Answer: 3

19. Which of the following is true about dark field microscopy?

(1) Adding a disc called ‘stop’ to the condenser will make a bright field to dark filed

(2) The stop disc prevents the entry of light from the central field and the object is illuminated with a beam of light

(3) The light gets reflected from the sides of the specimen and appears bright in the dark background

(4) All of these

Answer: 4

20. The magnification power of a compound microscope does not depend upon_______

(1) The focal length and aperture of the eye lens

(2)’The apertures of the objective lens

(3) Tube length of the microscope

(4) None of the above

Answer: 2

21. Resolving power of a microscope depends upon________

(1) The focal length and aperture of the eye lens

(2) The focal length and objective of the eye lens

(3) The apertures of the objective and the eye lens

(4) The wavelength of light illuminating the object

Answer: 4

22. Resolving power of a microscope is a function of ____________

(1) Wavelength of light used

(2) Numerical aperture of the lens system

(3) Refractive index

(4) Wavelength of light used and numerical aperture of the lens system

Answer: 4

23. In fluorescence microscopy, which of the following performs the function of removing all light except the blue light?

(1) Exciter filter

(2) Barrier filter

(3) Dichroic mirror

(4) Mercury arc lamp

Answer: 1

24. Which of the following is true for electron microscopy?

(1) specimen should be thin and dry

(2) image is obtained on a phosphorescent screen

(3) electron beam must pass through the evacuated chamber

(4) specimen should be thin and dry, image is obtained on a phosphorescent screen and electron beam must pass through evacuated chamber

Answer: 4 

25. What is the image formed by the microscope to the observer______

A. Real image

B. virtual image

C. Upright, enlarged virtual image

D. inverted, magnified virtual image

Answer: D

26. The tools used to observe onion epidermal cells and snail crawling are_________

A. microscope, magnifying glass

B. magnifying glass, magnifying glass

C. microscope, microscope

D. magnifying glass, microscope

Answer: A

27. The common feature of telescopes and microscopes is__________

A. Helps to see small objects clearly

B. Helps to see distant objects clearly

C. Both consist of two convex lenses

D. Both consist of two plane mirrors

Answer: C

28. When using a microscope, the distance between the object to be observed and the objective lens is__________

A. greater than the focal length

B. less than the focal length

C. Less than 2 times the focal length and greater than 1 times the focal length

D. greater than 2 times the focal length

Answer: C

29. If we want to observe the cells of plants, we should use________

A. plane mirror

B. Magnifying glass

C. Microscope

D. a telescope

Answer: C

30. Regarding microscopes, which of the following statements is correct_____________

A. The object becomes a magnified real image through the eyepiece

B. The object becomes a magnified virtual image through the objective lens

C. the role of the eyepiece is equivalent to a magnifying glass

D. the role of the eyepiece is equivalent to a projector

Answer: C

31. During the biological experiment class, Rakesh found that the eyepiece and the objective lens were marked with 5x and 10x respectively, then the magnification of the microscope he used was_______

A. 5 times

B. 10 times

C. 15 times

D. 50 times

Answer: D

32. If you want to carefully observe the internal structure of a leaf, it is best to use________

A. plane mirror

B. Concave lens

C. magnifying glass

D. a microscope

Answer: D

33. Which of the following statements about microscopes and telescopes is correct___________

A. The astronomical telescope sees distant stars because the stars form a magnified image through the objective lens

B. In 1609, Galileo invented the first microscope

C. The microscope can be composed of a convex lens and a concave lens

D. The eyepieces of microscopes and telescopes work as a magnifying glass

Answer: D

34. Among the following four eyepiece and objective lens combinations, the one with the largest magnification is________

A. Eyepiece 5×; Objective 10 ×

B. eyepiece 10×; objective lens 10×

C. eyepiece 5×; objective lens 40×

D. eyepiece l0×; objective lens 40×

Answer: D

35. Which of the following optical elements is equivalent to the imaging of the objective lens of the microscope?

A. camera 

B. Projector 

C. magnifying glass

D. periscope 

Answer: B

 36. Which of the following statements about observation is incorrect is_________

A. The scope of observation can be expanded with a microscope

B. More accurate data can be obtained by observing celestial bodies with astronomical telescopes

C. Use a magnifying glass to observe fingerprints more clearly

D. The observation results using the instrument must be correct

Answer: D

37. Which of the following statements is correct_______

A. The eyepiece of a microscope is a concave lens

B. The eyepiece of the telescope is composed of a concave lens

C. convex lens is characterized by thick middle and thin edge

D. The light screen of the camera is an inverted enlarged real image

Answer: C

What is a microscope?

• The microscope is an instrument that allows you to observe objects that are not perceptible to the naked eye. 
• The invention of the microscope, attributed to Galileo, was actually the result of improvements made by the Dutch naturalist Antony van Leeuwenhoek, who used it to observe living beings.
• The microscope was invented to enlarge or enlarge images of objects not visible to the naked eye. The resolving power of current microscopes is 0.2 µm, about a thousand times more than the human eye.
• The purpose of microscopy is to obtain enlarged images of an object, which allow us to distinguish details not revealed to the naked eye.
• An object table with a preparation driver is necessary for convenient placement of the test samples and moving the preparation to search for an area of ​​interest.
• The focusing mechanism allows, by changing the distance from the objective to the test sample, to achieve the clearest image. The focus mechanism has a coarse and fine focus knob.
• Lenses are complex optical-mechanical systems consisting of a complex of lenses interconnected in a certain sequence, designed to obtain an image with the appropriate magnification, resolution, and color accuracy.
• Eyepieces – optical systems designed to transfer the image of the drug to the retina of the observer’s eye. They have an anti-reflective coating and allow you to work both with glasses and without glasses.
• The lighting system is a system of lenses, diaphragms, and mirrors that provides uniform illumination of the object. Consists of a condenser and a LED or halogen lamp.

How to use a microscope: 

• Setting up the device
• If you are interested in how to use a Levenhuk microscope, please note that most models allow you to change the lens right during observations by turning the turret. 
• To start working with a Leeuwenhoek or Bresser device, you need to select the optics with the lowest magnification and carry out the basic settings.
• Place the slide with the preparation (slide) on the stage and bring it closer to the objective at a distance of 3-4 mm.
• Using the microscope sequence, use the coarse adjustment wheel to slowly move the observation specimen away from the objective. You need to do this until the image becomes clear.
• Gently turn the fine adjustment wheel until the picture is as sharp as possible.

Rules to use Microscope:

• The basic rules for working with a microscope say that the object stage or objective must be moved away. If you look through the eyepiece and at the same time bring the preparation closer, it is easy to damage the stage or the optics. 
• The methods of working with a microscope are very simple: to change the maximum degree of magnification, it is enough to turn the turret until a characteristic click is heard. 
• But it is also necessary to do this under supervision: optics with higher magnification are longer and can catch on a glass slide. 
• Therefore, you need to work with the microscope very carefully, if necessary, repeating the setting for each objective separately.
• If you are using a binocular instrument, all the steps described above must be carried out using only one eyepiece. 
• The second, when preparing the microscope for work, is easy to adjust using the adjusting ring. 
• The accuracy of this adjustment is easy to determine: looking into the eyepieces with both eyes, the user should see only one high-definition image.
• By knowing how to use a microscope correctly, you are guaranteed to make many personal discoveries! Learn the amazing secrets of the world around you right at home.

How does an optical microscope work?

• The microscope is one of the most important inventions in human history. Today, it is very easy to buy this optical device for home research, education, and leisure. 
• To make your observations as informative as possible, it is important to understand the essence of the microscope. 
• This will help to properly prepare it for observations and use all the capabilities of the device.
• The principle of operation of an optical microscope is quite simple: a diverging beam of light passes through the sample, and the resulting image is magnified by the objective, refracted to enter the eyepiece tube, where it is magnified again. After that, a beam of light enters the retina of the eye, forming an image.
• The device and the principle of operation of the microscope may differ slightly for different models. For example, in professional electronic devices, an electron beam passes through the sample, which is captured by special magnetic lenses. However, the basic principle of the microscope remains unchanged.