MCQ on Microscope Part 1

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1. You place a specimen under the microscope and notice that parts of the specimen begin to emit light immediately. These materials can be described as _____________.

A. fluorescent
B. phosphorescent
C. transparent
D. opaque

2. Who is the probable inventor of the compound microscope?

A. Girolamo Fracastoro
B. Zaccharias Janssen
C. Antonie van Leeuwenhoek
D. Robert Hooke

3. Which would be the best choice for viewing internal structures of a living protist such as a
Paramecium?

a. a brightfield microscope with a stain
b. a brightfield microscope without a stain
c. a darkfield microscope
d. a transmission electron microscope

4. Which type of microscope is especially useful for viewing thick structures such as biofilms?

a. a transmission electron microscope
b. a scanning electron microscopes
c. a phase-contrast microscope
d. a confocal scanning laser microscope
e. an atomic force microscope

5. Which type of microscope would be the best choice for viewing very small surface structures of a
cell?

a. a transmission electron microscope
b. a scanning electron microscope
c. a brightfield microscope
d. a darkfield microscope
e. a phase-contrast microscope

6. Which of the following has the highest energy?

A. light with a long wavelength
B. light with an intermediate wavelength
C. light with a short wavelength
D. It is impossible to tell from the information given.

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

A. Hans Janssen
B. Zaccharias Janssen
C. Antonie van Leeuwenhoek
D. Robert Hooke

8. What type of microscope uses an annular stop?

a. a transmission electron microscope
b. a scanning electron microscope
c. a brightfield microscope
d. a darkfield microscope
e. a phase-contrast microscope

9. What type of microscope uses a cone of light so that light only hits the specimen indirectly,
producing a darker image on a brighter background?

a. a transmission electron microscope
b. a scanning electron microscope
c. a brightfield microscope
d. a darkfield microscope
e. a phase-contrast microscope

10. What mordant is used in Gram staining?

A. crystal violet
B. safranin
C. acid-alcohol
D. iodine

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

A. Only the TEM specimen requires sputter coating.
B. Only the SEM specimen requires sputter-coating.
C. Only the TEM specimen must be dehydrated.
D. Only the SEM specimen must be dehydrated.

12. What is the ratio of resolving power of an optical microscope for wavelengths λ1= 4000 Å and λ2= 6000 Å?

a. 2:3
b. 3:2
c. 6:25
d. 16:9

13. Two identical glass (μ =3/2) equi – convex lenses of focal length f each are kept in
contact. The space between the two lenses is lled with water ((μ =4/3). The focal length
of the combination is

a. f/3
b. f
c. 4f/3
d. 3f/4

14. The objective and the eye-piece of the compound microscope having a focal length of
0.95 cm and 5 cm, respectively, are kept at a distance of 20 cm. At a distance of 25 cm
the large image is formed. Calculate the total magnication.

a. 84
b. 80
c. 94
d. 75

15. A vertical microscope is focused on a point at the bottom of an empty tank. Then
water (μ=4/3) is poured into the tank up to a height of 4 cm. After which a liquid that does
not mix with water is poured over it up to a height of 2 cm above the water. The refractive
index of the liquid is 3/2. What should be the vertical distance through which the
microscope must be moved to bring the object in focus again?

a. 2.61 cm
b. 1.67 cm
c. 5 cm
d. 4.1 cm

16. Using a microscope a glass plate of 5 mm is viewed from the above. The microscope
is lowered by 3 mm to view the bottom surface of the glass. What is the refractive index
of the glass?

a. 2
b. 1.66
c. 2.25
d. 1.4

17. A microscope is used to focus on an object at the bottom of a beaker. The microscope
is raised by 1 cm. To what height should the water be poured to bring the object in focus
again. Refractive index of water is 4/3.

a. 1 cm
b. 4/3 cm
c. 4 cm
d. 3 cm

18. Resolving power of light microscope is

a. 2 mm
b. 0.2 mm
c. 0.1 mm
d. 1 mm

19. Differentiation capacity of a compound microscope is

a. 27.5 μm
b. 2.75 μm
c. 0.275 μm
d. None

20. The magnication power of a compound microscope does not depend upon

a. The focal length and aperture of the eye lens
b. The apertures of the objective lens
c. Tube length of the microscope
d. None of the above

21. Resolving power of a microscope depends upon

a. The focal length and aperture of the eye lens
b. The focal length and objective of the eye lens
c. The apertures of the objective and the eye lens
d. The wavelength of light illuminating the object

1. C, 2. A, 3. D, 4. B, 5. C, 6. D, 7. B, 8. E, 9. D, 10. D, 11. B, 12.B, 13.D, 14.C, 15.B, 16.b, 17.C, 18.B, 19.C, 20.B, 21.D