Forensics CH.7
The bending of light is known as what
. refraction
The maximum useful magnification of a compound microscope is approximately _______ times the numerical aperture of the objective being used.
1000
In its usual mode, the scanning electron microscope (SEM) has a magnification that ranges from
10x-100,000x
If an eyepiece lens with a magnification of 10x is combined with a 45x objective, the respective magnification will be:
450x
List the parts of the mechanical system of a compound microscope.
Base, Arm, Stage, Body tube, Coarse Adjustment Knob, Fine Adjustment Knob
True or False: Of the different types of microscopes available for scientific use, only the polarizing microscope is not applicable for the examination of forensic specimens.
F
True or False: The magnification of a microscope with a 10X eyepiece and a 10X objective will be 1000X.
F
True or False: The polarizing microscope is best used for forensic microscopy requiring a side-by-side comparison.
F
True or False: With the development of the scanning electron microscope, a forensic analyst can now view a particle under a microscope while, at the same time, a beam of light is directed at the particle in order to obtain its absorption spectrum.
F
List the parts of the optical system of a compound microscope.
Illuminator, Condenser, objective lens, eyepiece lens
Which microscope creates an image using a beam of electrons?
Scanning Electron Microscope (SEM)
Which microscope gives a 3-dimensional image?
Scanning Electron microscope (sem)
True or False: Light that is confined to a single plane of vibration is said to be plain-polarized and requires special means to detect it.
T
True or False: The earliest and simplest microscope was the magnifying glass.
T
True or False: The major attractions of the scanning electron microscope image are its high magnification.
T
True or False: The mechanical system of a microscope is composed of six parts.
T
True or False: The stereoscopic microscope is the most frequently used and versatile microscope found in the crime laboratory.
T
This describes a microscope with two eyepieces
binocular
Which microscope is used when looking at different specimen side-by-side?
comparison microscope
What is known as the lens system under a microscope stage that collects light rays from the base illuminator: often has an iris diaphragm.
condenser
The thickness of a specimen that is entirely under a microscope
depth of focus
Parts of a microscope
eyepiece, objective lens, fine adjustment know, course adjustment knob, stage, stage clips, diaphragm
List the types of physical evidence that the micro-spectrophotometer is used to analyze.
fibers, paints, inks
The area of the specimen that can be seen after it is magnified
field of view
What are the major attractions of the scanning electron microscope (SEM)
high resolution, high magnification, great depth of focus
The "fingerprint" IR spectrum can be seen using a(n) __ microscope
microspectrophotometer
Which instrument links a microscope to a spectrophotometer?
microspectrophotometer
This describes a microscope with one eyepiece
monocular
How do you calculate the magnification of a microscope?
objective lens
The lower lens of a compound microscope that is positioned directly over the specimen is known as what?
objective lens
The upper lens of a compound microscope is called what?
objective lens
This describes a microscope that keeps a specimen in focus even after rotating the objective lens.
parfocal
The polarizer and the analyzer must be ____________ to avoid extinction.
perpendicular
34. A device that permits the passage of light waves vibrating in only one plane
polarizer
Which microscope has found wide application for the examination of birefringent materials present in soil?
polarizing microscope
An image that can be seen directly with the naked eye is called what
real image
What kind of evidence is a polarizing microscope used for?
soil, glass
Which microscope is the most frequently used and versatile microscope found in the crime laboratory?
stereoscopic microscope
What type of illumination occurs when light that passes up from the condenser and through the specimen?
transmitted illumination
What type of illumination of a specimen comes from above (for opaque specimen)?
vertical or refracted illumination
An image that cannot be seen directly, but can be seen only by a viewer looking through a lens is called what?
virtual image
