Test 02 Forensic Science 1

Practice Chapter 08 - Microscope

Stereoscopic Microscope

  • The stereoscopic microscope is the most frequently used microscope in a crime lab.
    FALSE statement: It is not the most frequently used microscope as stated.

Magnifying Power and Depth of Focus

  • As magnifying power increases, the microscope’s depth of focus decreases.
    TRUE statement: This is a true assertion about the relationship between magnification and depth of focus.

Scanning Electron Microscope

  • The scanning electron microscope produces an image by aiming a beam of electrons onto a specimen.
    TRUE statement: This statement correctly describes how a scanning electron microscope operates.

Components of a Compound Microscope

  • Components of a compound microscope include all of the following except: Expander (not a typical component).

    • Palynology is the study of Spores.

Microscope Lens Inscription

  • Each microscope lens is inscribed with a number signifying its Magnification.

Virtual Image

  • The image seen through a compound microscope is a Virtual Image.

  • A compound microscope consists of two lenses mounted at each end of a narrow tube.

Practice Chapter 09 - Firearms

Dermal Nitrate Test

  • The "dermal nitrate test" does not give misleading positive reactions to: Chocolate.

Shotgun Gauge

  • Generally, the gauge of a shotgun is directly related to the diameter of its barrel.

Tool Mark Photography

  • When removal of the original tool mark is impossible, the criminalist photographs the marked area to scale and makes a cast of the mark.
    TRUE statement: Emphasizes the importance of documentation in forensics.

National Integrated Ballistic Information Network (NIBIN)

  • HIBIN is the National Integrated Ballistic Information Network, a unified firearm search system.
    TRUE statement: Highlights the role of NIBIN in firearms identification.

Primer Residue Detection

  • The approach for primer residue detection is its enhanced specificity over hand swabs.
    TRUE statement: This indicates advancements in residue detection methods.

Bore Components

  • Lands are the original part of the bore from which rifling grooves are formed.

Comparison Microscope

  • The most important instrument for comparing bullets is arguably the Comparison Microscope.

The Microscope

Types of Microscopes Applicable in Forensics

  1. The compound microscope

  2. The comparison microscope

  3. The stereoscopic microscope

  4. The polarizing microscope

  5. The microspectrophotometer

Definition of a Microscope

  • A microscope is defined as an optical instrument that uses a lens or a combination of lenses to magnify and resolve the fine details of an object.

Comparison Microscope Definition

  • The comparison microscope uses a bridge to join two independent objective lenses into a single binocular unit.

Polarizing Microscope Definition

  • The polarizing microscope forms images by aiming a beam of electrons onto the specimen.

Microspectrophotometer Definition

  • The microspectrophotometer can be used to obtain the absorption spectrum of a specimen.

Scanning Electron Microscope Details

  • The scanning electron microscope is used to determine the elemental composition of a specimen.

  • The objective lens forms an image of the object that is real, inverted, and magnified.

Compound Microscope Light Collection

  • The condenser collects light rays from the base.

Firearms and Tool Marks

Types of Firearms

  1. Swing-out revolver

  2. Semiautomatic pistol

  3. Bolt-action long gun

  4. Semiautomatic long gun

  5. Shotguns

Shotgun Barrel Description

  • The barrel of a shotgun is smooth, without grooves and lands.

FBI's Drugfire Initiative

  • In the early 1990s, the FBI launched Drugfire.

Shotgun Pellet Dynamics

  • Pattern, speed, and distance of pellets from a shotgun are affected by the Choke configuration of the shotgun.

Gunpowder Residue Testing Conflicts

  • The dermal nitrate test can give conflicting positive reactions with cosmetics, crime scene debris, and tobacco.

Raising Serial Numbers on Steel Surfaces

  • A solution of hydrochloric acid, copper chloride, and water works well to raise a serial number on a steel surface.

Hairs and Fibers

Structure of Hair Shaft

  • The hair shaft is made up of three layers:

    1. Medulla

    2. Cortex

    3. Cuticle

Natural Fibers

  • Natural fibers are derived entirely from animal or plant sources:

    • Examples include Wool, Fur, Cotton, and Cashmere.

Manufactured Fibers

  • Manufactured fibers include:

    • Polyester

    • Rayon

    • Nylon

    • Acrylics

Cuticle Definition

  • The cuticle is the scale structure covering the exterior of the hair.

Cortex Definition

  • The cortex is the main body of the hair shaft.

Medulla Definition

  • The medulla is a cellular column running through the center of the hair.

Stages of Hair Growth

  1. Anagen Phase: The root bulb is flame-shaped.

  2. Catagen Phase: The root is elongated.

  3. Telogen Phase: The root is club-shaped.

First Step in Forensic Hair Examination

  • The first step of forensic examinations is the examination of color, structure, and morphology of the hair.

Cuticle Structure Recap

  • The scale structure covering the exterior of the hair is known as the Cuticle.

First Manufactured Fiber

  • The first manufactured fiber to be produced was Rayon.