Micro Chapter 2 Flashcards
The degree to which a substance bends light is known as the A) Resolution B) Numerical aperture C) Refractive index D) Magnification
C
When light passes from air to a medium with a great refractive index (i.e., glass), what happens to the light?
A) The velocity of light decreases and it bends away from the normal
B) The velocity of light decreases and it bends toward the normal
C) The velocity of light increases and it bends away from the normal
D) The velocity of light increases and it bends toward the normal
B
Which of the following best describes how a lens works?
A) Light rays strike the lens and scatter
B) Light rays strike the lens and converge onto a focal point
C) Light rays move through the lens without changing direction
D) None of the above
B
A microscope that can remain in focus when the objective lens is changed is described as A) Refractive B) Magnified C) Parfocal D) All of the above
C
The total magnification of a bright-field microscope with a 10X eyepiece on the high power (100X) objective would be A) 100X B) 110X C) 1000X D) 10,000X
C
The ability of a lens to separate or distinguish between small objects that are close together is called A) Magnification B) Numerical aperture C) Refractive index D) Resolution
D
Which of the following changes would increase the resolution of a specimen observed through a lens? A) Decrease the wavelength of light B) Increase the refractive index C) Increase the numerical aperture D) All of the above
D
Immersion oil is used when observing specimens under high power because
A) It decreases the refractive index; this increases the numerical aperture
B) It increases the refractive index; this decreases the numerical aperture
C) It decreases the refractive index; this decreases the numerical aperture
D) It increases the refractive index; this increases the numerical aperture
A
The distance between the front surface of the lens and the surface of the cover glass or specimen is called the A) Numerical aperture B) Focal length C) Working distance D) Resolution
C
The best resolution achieved by bright-field microscopes is approximately A) 10 micrometers B) 1 micrometer C) 0.2 micrometers D) 0.2 nanometers
C
A bright-field microscope is best for observing which of the following types of specimens? A) Fixed, stained bacteria B) Unpigmented living cells C) Viruses D) Atoms
A
A dark-field microscope is best for observing which of the following types of specimens? A) Fixed, stained bacteria B) Unpigmented living cells C) Viruses D) Atoms
B
Which of the following microscopes are acceptable for viewing live specimens?
A) Dark-field microscope
B) Phase-contrast microscope
C) Differential interference contrast microscope
D) All of the above
D
The \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ microscope utilizes differences in refractive index and cell density into detectable variations in light intensity. A) Bright-field B) Dark-field C) Phase-contrast D) Electron
C
Which type of microscope would be best for observing microbial motility and observing endospores? A) Bright-field B) Dark-field C) Phase-contrast D) Electron
C