CHAPTER 4: CARE AND USE OF THE MICROSCOPE

Question 1

(1) Use of which one of the following type of objective lens causes the center of the microscope field to be in focus, whereas the periphery is blurred?

a. Plan achromatic
b. Achromatic
c. Plan apochromatic
d. Flat field

Answer 1

b. Achromatic

Question 2

(2) Which of the following gathers, organizes, and directs light through the specimen?

a. Eyepiece
b. Objective lens
c. Condenser
d. Optical tube

Answer 2

c. Condenser

Question 3

(3) After focusing a specimen by using the 40X objective, the laboratory professional switches to a 10X objective. The specimen remains in focus at 10X. Microscopes with this characteristic are described as:

a. Parfocal
b. Parcentric
c. Compensated
d. Parachromatic

Answer 3

a. Parfocal

Question 4

(4) Which objective has the greatest degree of color correction?

a. Achromatic
b. Plan apochromatic
c. Bichromatic
d. Plan achromatic

Answer 4

b. Plan apochromatic

Question 5

(5) In adjusting the microscope light using Koehler illumination, which one of the following is true?

a. Condenser is first adjusted to its lowest position
b. Height of the condenser is adjusted by removing the eyepiece
c. Image of the field diaphragm iris is used to center the condenser
d. Closing the aperture diaphragm increases the resolution of the image

Answer 5

c. Image of the field diaphragm iris is used to center the condenser

Question 6

(6) The total magnification obtained when a 10X eyepiece and a 10X objective lens are used is:

a. 1X
b. 10X
c. 100X
d. 1000X

Answer 6

c. 100X

Question 7

(7) After a microscope has been adjusted for Koehler illumination, and the specimen is being viewed with an oil immersion objective lens, light intensity should never be regulated by adjusting the:

a. Rheostat
b. Neutral density filter
c. Light control knob
d. Condenser

Answer 7

d. Condenser

Question 8

(8) The recommended cleaner for removing oil from objectives is:

a. 70% alcohol or lens cleaner
b. Xylene
c. Water
d. Benzene

Answer 8

a. 70% alcohol or lens cleaner

Question 9

(9) Which of the following types of microscopy is valuable in the identification of crystals that are double refractive?

a. Compound brightfield
b. Darkfield
c. Polarizing
d. Phase-contrast

Answer 9

c. Polarizing

Question 10

(10) A laboratory science student has been reviewing a hematology slide using the 10X objective to find a suitable portion of the slide for examination. He moves the 10X objective out of place, places a drop of oil on the slide, rotates the nosepiece so that the 40X objective passes through the viewing position, and continues to rotate the 100X oil objective into viewing position. This practice should be corrected in which way?

a. The stage of a parfocal microscope should be lowered before the objectives are rotated.
b. The 100X oil objective should be in place for viewing before the oil is added.
c. The drop of oil should be in place and the 100X objective lowered into the oil, rather than swinging the objective into the drop.
d. The objectives should be rotated in the opposite direction so that the 40X objective does not risk entering the oil.

Answer 10

d. The objectives should be rotated in the opposite direction so that the 40X objective does not risk entering the oil.

Question 11

(11) Darkfield microscopes create the dark field by:

a. Using two filters that cancel each other out, one above and the other below the condenser
b. Angling the light at the specimen so that it misses the objective unless something in the specimen bends it backward
c. Closing the condenser diaphragm entirely, limiting light to just a tiny ray in the center of the otherwise dark field
d. Using a light source above the specimen and collecting light reflected from the specimen, rather than transmittted through the specimen, so that when there is no specimen in place, the field is dark

Answer 11

b. Angling the light at the specimen so that it misses the objective unless something in the specimen bends it backward