ETC ETC Laboratory Analysis & Forensic Science 3

Question 1

What is locard's exchange principle and how does it apply to forensic analysis?

Accepted Answer

Every contact leaves a trace — evidence is transferred between persons and crime scenes during contact

Answer

Locard's Exchange Principle states that every contact between two objects results in material transfer, forming the basis for trace evidence analysis.

Question 2

Which reagent is used as a presumptive test for blood that produces a luminescent reaction?

Accepted Answer

Luminol

Answer

Luminol reacts with the iron in hemoglobin to produce chemiluminescence, allowing detection of blood even when diluted or cleaned.

Question 3

What is the role of a forensic laboratory's evidence custodian?

Accepted Answer

To maintain chain of custody records and control access to submitted evidence

Answer

The lab evidence custodian is responsible for receiving, logging, storing, and tracking all submitted evidence to maintain an unbroken chain of custody.

Question 4

Why must forensic analysts wear PPE including gloves and masks when handling evidence?

Accepted Answer

To prevent cross-contamination of the evidence with analyst DNA or materials

Answer

PPE prevents the analyst's DNA, fingerprints, or other materials from contaminating evidence, which could invalidate results or compromise a prosecution.

Question 5

Which type of evidence requires refrigeration at 2–8°C upon submission to the forensic laboratory?

Accepted Answer

Biological samples such as blood, saliva, and semen swabs

Answer

Biological samples degrade rapidly at room temperature; refrigeration at 2–8°C slows bacterial growth and enzymatic breakdown to preserve DNA integrity.

(ETC) Evidence Technician Certification Practice Test

(ETC) Evidence Technician Certification Practice Test

ETC ETC Laboratory Analysis & Forensic Science 3