Chapter 13: Metals, Paint & Soil

The emission spectrograph is used to determine​ the: A. Elemental composition of a substance. B. Crystalline structure of a substance. C. Mass of a substance. D. Weight of a substance.

A. Elemental composition of a substance.

A​ "fingerprint" of an element is obtained by the technique​ of: A. Emission spectroscopy. B. Ultraviolet spectrophotometry. C. Gas chromatography. D. Infrared spectrophotometry.

A. Emission spectroscopy.

Which would be LEAST useful in identifying a mineral​ crystal? A. Size B. Refractive index C. Color D. Geometric shape

A. Size

Which is NOT part of the composition of​ paint? A. Pigment B. Adhesive C. Binder D. Solvent

B. Adhesive

Which of the following statements is​ correct? A. All atoms of an element have the same atomic mass number. B. All atoms of an element have the same number of protons. 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.

B. All atoms of an element have the same number of protons.

Automobile finishes typically contain which​ layer(s)? A. Colorcoat B. An electrocoat​ primer, colorcoat, and clearcoat C. Electrocoat primer and colorcoat D. Clearcoat

B. 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

B. A​ hit-and-run.

Which coating helps resist UV radiation and acid​ rain? A. Clearcoat B. Basecoat C. Primer surface D. Electrocoat primer

B. Basecoat

In neutron activation​ analysis, an element is identified by measuring the energy of​ emitting: A. Electrons. B. Gamma rays. C. Protons. D. Neutrons.

B. 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.

B. Gamma rays.

The nucleus of an atom​ contains: A. Protons and electrons. B. Protons and neutrons. C. Neutrons. D. Neutrons and electrons.

B. Protons and neutrons.

The polymeric makeup of paint binders can readily be compared​ by: A. Emission spectroscopy. B. Pyrolysis gas chromatography. C. Microscopy. D. Thin-layer chromatography.

B. Pyrolysis gas chromatography.

Paint chips may be individualized to a single source by examining​ their: A. Relative size. B. Pyrograms. C. Color and layer structure. D. Ultraviolet spectra. E. Infrared spectra.

C. Color and layer structure.

Which property imparts paint with its most distinctive forensic​ characteristics? A. Gloss B. Texture C. Color-layer sequence D. Color

C. Color-layer sequence

What is the logical first step in soil​ analysis? A. Examination for presence of debris under​ low-power magnification B. Examination of minerals and rocks under​ high-power magnification C. Comparison of dried soil sample for color and texture D. Use of the​ density-gradient tube technique

C. Comparison of dried soil sample for color and texture

Which coating provides resistance to​ corrosion? A. Clearcoat B. Primer surface C. Electrocoat primer D. Basecoat

C. Electrocoat primer

Gamma rays​ are: A. Neutrons. B. Electrons. C. Electromagnetic radiation. D. Protons.

C. Electromagnetic radiation.

An element is selective in the frequency of light it will absorb. This selectivity is due to​ its: A. Number of neutrons. B. Atomic mass. C. Electron energy levels. D. Proton cloud.

C. Electron energy levels.

Atoms having the same atomic number but different atomic masses are​ called: A. Isotherms. B. Isobars. C. Isotopes. D. Isomers.

C. Isotopes.

The​ ________ properties of​ crystals, such as refractive index and​ birefringence, provide points of identification that help characterize them. A. Physical B. Amorphous C. Optical D. Chemical

C. Optical

The most abundant element of the​ earth's crust​ is: A. Carbon. B. Hydrogen. C. Oxygen. D. Aluminum.

C. Oxygen.

Which of the following statements is​ false? A. The neutron has no electrical charge. B. The proton has a charge of​ +1. C. The electron and proton have the same mass. D. Protons and neutron comprise the nucleus of an atom.

C. The electron and proton have the same mass.

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. Make B. Model C. Year D. All of the above

D. All of the above

Radioactivity is composed​ of: A. Gamma rays. B. Beta particles. C. Alpha particles. D. All of the above

D. All of the above

What type of evidence would be expected to have trace​ elements? A. Glass and metal objects B. Soil and gun primer particles C. Paint and bullet fragments D. All of the above

D. All of the above

Which coat represents the​ "eye appeal"? A. Electrocoat primer B. Clearcoat C. Primer surface D. Basecoat

D. Basecoat

Paint binders can be chemically analyzed​ using: A. TLC. B. Pyrolysis GC. C. IR spectrophotometry. D. Both B and C

D. Both B and C

In a simple emission​ spectrograph, excitation of the specimen under investigation is accomplished with​ a(n): A. Inductive magnetic field. B. Activated prism. C. Hot plasma torch. D. Electrical arc.

D. Electrical arc.

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. Compounds. C. Molecules. D. Isotopes.

D. Isotopes.

A continuous spectrum is most helpful in identifying a particular element because it serves as a unique​ "fingerprint" of an element. True or False

False

All atoms of an element have the same number of neutrons. True or False

False

Alpha particles are a form of radiation consisting of electrons. True or False

False

Emission spectroscopy measures the frequency of light emitted by an atom when one of its electrons moves to a higher orbital. True or 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 or False

False

Isotopes are atoms of the same element that have different numbers of protons in their respective nuclei. True or 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 or False

False

Surface texture is the most important of the characteristics that a criminalist looks for when comparing paint chips. True or False

False

The first step in a forensic soil comparison is analysis of the size of the particles. True or False

False

The minerals found in different soil samples cannot effectively be used to determine whether or not they have the same origin. True or False

False

The number of protons in the nucleus of an atom is called the atomic mass number. True or False

False

After the paint has been applied to a​ surface, the solvent evaporates. True or False

True

An atom has a net zero electrical​ charge, which indicates that it contains the same number of protons and electrons. True or False

True

Gamma rays are a​ high-energy form of electromagnetic radiation. True or False

True

Isotopes have different atomic mass numbers. True or False

True

Neutrons carry no charge. True or False

True

The concentration of the absorbing element is directly proportional to the quantity of the light absorbed. True or 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 or 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 or 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 or False

True