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 403 objective, the
   laboratory professional switches to a 103 objective. The
   specimen remains in focus at 103. 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 103 eyepiece and
   a 103 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 103 objective to find a suitable portion
    of the slide for examination. He moves the 103 objective
    out of place, places a drop of oil on the slide, rotates
    the nosepiece so that the 403 objective passes through
    the viewing position, and continues to rotate the 1003 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 1003 oil objective should be in place for viewing
    before the oil is added.
    c. The drop of oil should be in place and the 1003 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 403 objective does not risk entering the oil.

Answer 10

d. The objectives should be rotated in the opposite direction
so that the 403 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 transmitted 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