Fibers Chapter 6 Exam Questions and Answers With Verified Solutions 2025
Can fiber evidence have probative value? - ✔✔yes
What characteristics are indicative of synthetic fibers? - ✔✔Uniform shape of the cross section (can be
different shapes), stronger and more chemically inert
Can a piece of fabric be individualized to a particular garment? - ✔✔Yes for a piece of fabric, no for an
individual fiber. Fabric - yes if it can be proven that the fabric fits into a torn area of the garment. Fiber -
no, as fibers are class evidence. They have probative value, but are still class evidence.
What is the difference between a fabric and a fiber? - ✔✔Fabric is made from fibers. Fibers are made of
twisted elements that are either natural or artificial.
Is silk a synthetic or natural fiber? - ✔✔natural
What is the most common type of natural fiber? - ✔✔cotton
What is the most common type of synthetic fiber? - ✔✔nylon
Can an investigator use the way a fabric accepts a specific dye to identify & compare samples? - ✔✔yes
What is optical microscopy? - ✔✔The most important method of fiber identification that involves
polarizing light and comparison microscopes.
What is an electropherogram? - ✔✔plot of results from an analysis done by electrophoresis.
A gray cotton fiber was found on the red sweater of a victim. A gray cotton fiber was taken from a
suspect's sweatshirt. After testing 900 gray sweatshirts, the lab found the fiber matches 45 of them.
What is the probability that the crime scene fiber and that of the suspect matched simply by chance?
(Show your work) - ✔✔45/900 = 1/20 (0.05)
Can fiber evidence have probative value? - ✔✔yes
What characteristics are indicative of synthetic fibers? - ✔✔Uniform shape of the cross section (can be
different shapes), stronger and more chemically inert
Can a piece of fabric be individualized to a particular garment? - ✔✔Yes for a piece of fabric, no for an
individual fiber. Fabric - yes if it can be proven that the fabric fits into a torn area of the garment. Fiber -
no, as fibers are class evidence. They have probative value, but are still class evidence.
What is the difference between a fabric and a fiber? - ✔✔Fabric is made from fibers. Fibers are made of
twisted elements that are either natural or artificial.
Is silk a synthetic or natural fiber? - ✔✔natural
What is the most common type of natural fiber? - ✔✔cotton
What is the most common type of synthetic fiber? - ✔✔nylon
Can an investigator use the way a fabric accepts a specific dye to identify & compare samples? - ✔✔yes
What is optical microscopy? - ✔✔The most important method of fiber identification that involves
polarizing light and comparison microscopes.
What is an electropherogram? - ✔✔plot of results from an analysis done by electrophoresis.
A gray cotton fiber was found on the red sweater of a victim. A gray cotton fiber was taken from a
suspect's sweatshirt. After testing 900 gray sweatshirts, the lab found the fiber matches 45 of them.
What is the probability that the crime scene fiber and that of the suspect matched simply by chance?
(Show your work) - ✔✔45/900 = 1/20 (0.05)
