Deck 14: Metals, paint, and Soil

Question 1

Radioactivity is composed of:

A) Alpha particles.
B) Beta particles.
C) Gamma rays.
D) All of the above.

Answer 1

D

Question 2

A "fingerprint" of an element is obtained by the technique of:

A) Infrared spectrophotometry.
B) Ultraviolet spectrophotometry.
C) Gas chromatography.
D) Emission spectroscopy.

Answer 2

D

Question 3

The nucleus of an atom contains:

A) Neutrons.
B) Neutrons and electrons.
C) Protons and electrons.
D) Protons and neutrons.

Answer 3

D

Question 4

Neutron activation analysis involves bombarding specimens with neutrons and then measuring the resultant:

A) X rays.
B) Gamma rays.
C) Beta particles.
D) Alpha particles.

Question 5

Gamma rays are:

A) Electrons.
B) Protons.
C) Neutrons.
D) Electromagnetic radiation.

Question 6

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.

Question 7

The most abundant element of the earth's crust is:

A) Oxygen.
B) Hydrogen.
C) Carbon.
D) Aluminum.

Question 8

Which of the following statements is false?

A) Protons and neutron comprise the nucleus of an atom.
B) The proton has a charge of +1.
C) The neutron has no electrical charge.
D) The electron and proton have the same mass.

Question 9

Which of the following is a non-destructive technique for identifying and quantifying trace elements in a test sample?

A) Carbon arc emission spectrometry
B) ICP emission spectrometry
C) Neutron activation analysis
D) Infrared spectrophotometry

Question 10

Paint as physical evidence is most frequently encountered in:

A) Burglary.
B) A hit-and-run.
C) Car theft.
D) Both A and B

Question 11

In neutron activation analysis,an element is identified by measuring the energy of emitting:

A) Protons.
B) Electrons.
C) Neutrons.
D) Gamma rays.

Question 12

An element is selective in the frequency of light it will absorb.This selectivity is due to its:

A) Number of neutrons.
B) Proton cloud.
C) Atomic mass.
D) Electron energy levels.

Question 13

Which is NOT part of the composition of paint?

A) Solvent
B) Adhesive
C) Pigment
D) Binder

Question 14

The emission spectrograph is used to determine the:

A) Mass of a substance.
B) Weight of a substance.
C) Crystalline structure of a substance.
D) Elemental composition of a substance.

Question 15

Atoms having the same atomic number but different atomic masses are called:

A) Isobars.
B) Isotopes.
C) Isotherms.
D) Isomers.

Question 16

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.

Question 17

Which type of radiation is NOT given off by radioactive decay?

A) X rays
B) Gamma rays
C) Beta particles
D) Alpha particles

Question 18

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) Make
C) Year
D) All of the above

Question 19

What type of evidence would be expected to have trace elements?

A) Glass and metal objects
B) Paint and bullet fragments
C) Soil and gun primer particles
D) All of the above

Question 20

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.

Question 21

Paint binders can be chemically analyzed using:

A) TLC.
B) IR spectrophotometry.
C) Pyrolysis GC.
D) Both B and C

Question 22

The ________ properties of crystals,such as refractive index and birefringence,provide points of identification that help characterize them.

A) Physical
B) Chemical
C) Amorphous
D) Optical

Question 23

Neutrons carry no charge.

Question 24

Which would be LEAST useful in identifying a mineral crystal?

A) Size
B) Color
C) Geometric shape
D) Refractive index

Question 25

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

Question 26

The presence of trace elements is useful because they provide markers that may establish the source of a material.

Question 27

Paint chips may be individualized to a single source by examining their:

A) Infrared spectra.
B) Ultraviolet spectra.
C) Color and layer structure.
D) Pyrograms.
E) Their relative size.

Question 28

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

Question 29

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

Question 30

Automobile finishes typically contain which layers?

A) Colorcoat
B) An electrocoat primer, colorcoat, and clearcoat
C) Clearcoat
D) Electrocoat primer and colorcoat

Question 31

Which coating helps resist UV radiation and acid rain?

A) Electrocoat primer
B) Primer surface
C) Basecoat
D) Clearcoat

Question 32

Which coating provides resistance to corrosion?

A) Electrocoat primer
B) Primer surface
C) Basecoat
D) Clearcoat

Question 33

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

Question 34

What is the logical first step in soil analysis?

A) Examination for presence of debris under low-power magnification
B) Comparison of dried soil sample for color and texture
C) Use of the density-gradient tube technique
D) Examination of minerals and rocks under high-power magnification

Question 35

Isotopes have different atomic mass numbers.

Question 36

Which coat represents the "eye appeal"?

A) Electrocoat primer
B) Primer surface
C) Basecoat
D) Clearcoat

Question 37

Which property imparts paint with its most distinctive forensic characteristics?

A) Color-layer sequence
B) Color
C) Gloss
D) Texture

Question 38

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

Question 39

The polymeric makeup of paint binders can readily be compared by:

A) Emission spectroscopy.
B) Thin-layer chromatography.
C) Microscopy.
D) Pyrolysis gas chromatography.

Question 40

Mutilated bullets are often not suitable for traditional microscopic comparisons against an exemplar test-fired bullet.

Question 41

The investigator should not try to remove trace paint evidence found on a tool but package the tool for laboratory examination instead.

Question 42

The major advantage of neutron activation analysis is that it provides a nondestructive method for identifying and quantitating trace elements.

Question 43

All atoms of an element have the same number of neutrons.

Question 44

A(n)________ spectrum shows a continuous band of colors all blending into one another.

Question 45

Alpha particles are a form of radiation consisting of electrons.

Question 46

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.

Question 47

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.

Question 48

Neutron activation analysis is favored in crime laboratories because of its low cost and ease of use.

Question 49

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.

Question 50

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

Question 51

A ________ element is an element found in very small quantities.

Question 52

A(n)________ spectrum shows a series of lines separated by black areas in which each line represents a definite wavelength of frequency.

Question 53

If soil is found adhering to an object,the investigator should remove the soil particles form the object and send them to the laboratory.

Question 54

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

Question 55

Gamma rays are a high-energy form of electromagnetic radiation.

Question 56

Emission,spectroscopy and neutron activation analysis do not provide any information as to how the elements are combined into compounds.

Question 57

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

Question 58

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

Question 59

After the paint has been applied to a surface,the solvent evaporates.

Question 60

Elements selectively absorb and emit ________.

Question 61

Soil is collected as ________ to preserve a record of the buildup of several layers of soil from different locations over time.

Question 62

When an electron moves to a lower-energy orbital,it ________ energy.

Question 63

A thorough comparison of paint must include a chemical analysis of the paint's pigments and ________ composition.

Question 64

A suspect has been found miles from the scene of a murder.Soil is found adhering to the suspect's shoe.Describe the proper collection and preservation of soil evidence that will permit a thorough comparison of the soil on the shoe to soil at the crime scene.

Question 65

Describe the process of neutron activation analysis.How does the process allow a forensic scientist to identify an isotope?

Question 66

Explain how the analysis of trace elements was important to the investigation of the assassination of President John.F.Kennedy.

Question 67

ICP emission spectrophotometry can be used to obtain an ________ profile of the questioned bullet fragment for comparison against an unfired bullet generally found in the possession of the suspect.

Question 68

Alpha particles are a type of radiation composed of ________ atoms minus their orbiting electrons.

Question 69

A(n)________ is a naturally occurring crystalline solid that can be identified by its physical properties.

Question 70

Match the word in Column 1 to its definition in Column 2.Each answer can only be used once.

A)An atom differing from another atom of the same element in the number of neutrons in its nucleus
B)A type of emission spectrum showing a series of lines separated by black areas
C)A particle with no electrical charge that is one of the basic structures in the nucleus of an atom
D)The state in which an atom absorbs energy and an electron moves from a lower to a higher energy level
E)A negatively charged particle that is one of the fundamental structural units of the atom
F)Light emitted from a source and separated into its component colors or frequencies
G)The number of protons in the nucleus of an atom
H)The sum of the number of protons and neutrons in the nucleus of an atom
I)The path of electrons as they move around the nuclei of atoms
J)A positively charged particle that is one of the basic structures in the nucleus of an atom
1)Atomic mass
2)Atomic number
3)Electron
4)Emission spectrum
5)Isotope
6)Line spectrum
7)Neutron
8)Proton
9)Electron Orbital
10)Excited State

Question 71

________ is the emission of radiation that accompanies the spontaneous disintegration of unstable nuclei.

Question 72

When comparing paint chips under a microscope,a criminalist looks for color,surface texture,and ________ layer sequence.

Question 73

An electron moves to a ________-energy orbital when it absorbs energy,such as heat or light.

Question 74

How does a nuclear reactor generate radioactive elements?

Question 75

________ are atoms of the same element that have different numbers of neutrons in their respective nuclei.

Question 76

The three basic subatomic particles are the proton,electron,and ________.

Question 77

The three types of radiation are alpha particles,beta particles,and ________ rays.

Question 78

Pyrolysis gas chromatography produces a pattern or ________ of the polymers that identify the specific chemical makeup of the binder.

Question 79

________ as physical evidence is most frequently encountered in hit-and-run cases.

Question 80

Paint specimens are best compared side by side under a ________ microscope.