chapter 13- metals, paint, and soil
Which is NOT part of the composition of paint? A. Solvent B. Binder C. Adhesive D. Pigment
Adhesive
Which of the following statements is correct? A. All atoms of an element have the same number of protons. B. All atoms of an element have the same atomic mass number. C. All atoms of an electron have the same number of neutrons. D. All atoms of an element have an equal number of neutrons and electrons.
All atoms of an element have the same number of protons.
After examining small paint chips from an auto accident scene and using the PDQ database, the crime lab worker can determine the ________ of the vehicle. A. Model B. Year C. Make D. All of the above
All of the above
Radioactivity is composed of: A. Beta particles. B. Alpha particles. C. Gamma rays. D. All of the above
All of the above
What type of evidence would be expected to have trace elements? A. Paint and bullet fragments B. Soil and gun primer particles C. Glass and metal objects D. All of the above
All of the above
Automobile finishes typically contain which layer(s)? A. Electrocoat primer and colorcoat B. An electrocoat primer, colorcoat, and clearcoat C. Clearcoat D. Colorcoat
An electrocoat primer, colorcoat, and clearcoat
Paint as physical evidence is most frequently encountered in: A. Burglary. B. A hit-and-run. C. Car theft. D. Both A and B
A hit-and-run.
Which coat represents the "eye appeal"? A. Basecoat B. Clearcoat C. Primer surface D. Electrocoat primer
Basecoat
Which coating helps resist UV radiation and acid rain? A. Electrocoat primer B. Primer surface C. Basecoat D. Clearcoat
Basecoat
Paint binders can be chemically analyzed using: A. TLC. B. IR spectrophotometry. C. Pyrolysis GC. D. Both B and C
Both B and C (IR Spectrophotometry and Pyrolysis GC)
Paint chips may be individualized to a single source by examining their: A. Color and layer structure. B. Ultraviolet spectra. C. Relative size. D. Pyrograms. E. Infrared spectra.
Color and layer structure.
What is the logical first step in soil analysis? A. Comparison of dried soil sample for color and texture B. Examination for presence of debris under low-power magnification C. Examination of minerals and rocks under high-power magnification D. Use of the density-gradient tube technique
Comparison of dried soil sample for color and texture
In a simple emission spectrograph, excitation of the specimen under investigation is accomplished with a(n): A. Electrical arc. B. Inductive magnetic field. C. Hot plasma torch. D. Activated prism.
Electrical arc.
Which coating provides resistance to corrosion? A. Electrocoat primer B. Clearcoat C. Primer surface D. Basecoat
Electrocoat primer
Gamma rays are: A. Electrons. B. Electromagnetic radiation. C. Neutrons. D. Protons.
Electromagnetic radiation.
An element is selective in the frequency of light it will absorb. This selectivity is due to its: A. Proton cloud. B. Atomic mass. C. Electron energy levels. D. Number of neutrons.
Electron energy levels.
The emission spectrograph is used to determine the: A. Mass of a substance. B. Weight of a substance. C. Elemental composition of a substance. D. Crystalline structure of a substance.
Elemental composition of a substance.
A "fingerprint" of an element is obtained by the technique of: A. Emission spectroscopy. B. Infrared spectrophotometry. C. Gas chromatography. D. Ultraviolet spectrophotometry.
Emission spectroscopy.
A continuous spectrum is most helpful in identifying a particular element because it serves as a unique "fingerprint" of an element. True False
False
All atoms of an element have the same number of neutrons. True False
False
Alpha particles are a form of radiation consisting of electrons. True False
False
Emission spectroscopy measures the frequency of light emitted by an atom when one of its electrons moves to a higher orbital. True False
False
If soil is found adhering to an object, the investigator should remove the soil particles from the object and send them to the laboratory. True False
False
Isotopes are atoms of the same element that have different numbers of protons in their respective nuclei. True False
False
It is not necessary that the collected paint from a vehicle involved in a hit-and-run accident be close to the area of the car suspected of being in contact with the victim. True False
False
Neutron activation analysis is favored in crime laboratories because of its low cost and ease of use. True False
False
Surface texture is the most important of the characteristics that a criminalist looks for when comparing paint chips. True False
False
The first step in a forensic soil comparison is analysis of the size of the particles. True False
False
The minerals found in different soil samples cannot effectively be used to determine whether or not they have the same origin. True False
False
The number of protons in the nucleus of an atom is called the atomic mass number. True False
False
In neutron activation analysis, an element is identified by measuring the energy of emitting: A. Electrons. B. Gamma rays. C. Protons. D. Neutrons.
Gamma rays
Neutron activation analysis involves bombarding specimens with neutrons and then measuring the resultant: A. Alpha particles. B. Gamma rays. C. X-rays. D. Beta particles.
Gamma rays
Atoms having the same atomic number but different atomic masses are called: A. Isobars. B. Isotopes. C. Isomers. D. Isotherms.
Isotopes
The atoms of hydrogen, deuterium, and tritium all have the same number of protons, but differ in the number of neutrons they possess. These substances are: A. Elements. B. Molecules. C. Compounds. D. Isotopes.
Isotopes
Which of the following is a non-destructive technique for identifying and quantifying trace elements in a test sample? A. Neutron activation analysis B. Carbon arc emission spectrometry C. ICP emission spectrometry D. Infrared spectrophotometry
Neutron activation analysis
The ________ properties of crystals, such as refractive index and birefringence, provide points of identification that help characterize them. A. Optical B. Chemical C. Amorphous D. Physical
Optical
The most abundant element of the earth's crust is: A. Oxygen. B. Carbon. C. Aluminum. D. Hydrogen.
Oxygen
The nucleus of an atom contains: A. Protons and neutrons. B. Protons and electrons. C. Neutrons. D. Neutrons and electrons.
Protons and neutrons.
The polymeric makeup of paint binders can readily be compared by: A. Emission spectroscopy. B. Microscopy. C. Thin-layer chromatography. D. Pyrolysis gas chromatography.
Pyrolysis gas chromatography.
Which would be LEAST useful in identifying a mineral crystal? A. Geometric shape B. Color C. Size D. Refractive index
Size
Which of the following statements is false? A. The electron and proton have the same mass. B. The neutron has no electrical charge. C. The proton has a charge of +1. D. Protons and neutron comprise the nucleus of an atom.
The electron and proton have the same mass.
After the paint has been applied to a surface, the solvent evaporates. True False
True
An atom has a net zero electrical charge, which indicates that it contains the same number of protons and electrons. True False
True
Emission, spectroscopy and neutron activation analysis do not provide any information as to how the elements are combined into compounds. True False
True
Gamma rays are a high-energy form of electromagnetic radiation. True False
True
Isotopes have different atomic mass numbers. True False
True
Mutilated bullets are often not suitable for traditional microscopic comparisons against an exemplar test-fired bullet. True False
True
Neutrons carry no charge. True False
True
The concentration of the absorbing element is directly proportional to the quantity of the light absorbed. True False
True
The investigator should not try to remove trace paint evidence found on a tool but package the tool for laboratory examination instead. True False
True
The major advantage of neutron activation analysis is that it provides a nondestructive method for identifying and quantitating trace elements. True False
True
The presence of trace elements is useful because they provide markers that may establish the source of a material. True False
True
The variety of coatings applied to the body of an automobile adds significant diversity to automobile paint and contributes to the forensic significance of automobile paint comparisons. True False
True
Standard/reference soil samples should be collected at the site of the crime at various intervals within a 100-foot radius of the crime scene. True False
True
Which type of radiation is NOT given off by radioactive decay? A. Gamma rays B. Alpha particles C. Beta particles D. X- rays
X- rays
ICP emission spectrophotometry can be used to obtain a(n) ________________________ profile of the questioned bullet fragment for comparison against an unfired bullet generally found in the possession of the suspect.
elemental
Which property imparts paint with its most distinctive forensic characteristics? A. Gloss B. Color C. Texture D. Color-layer sequence
Color-layer sequence