UGC NTA NET/JRF Exam, Forensic Science, January-2025

Hans Gross, an Austrian criminal jurist, is regarded as the "father of criminalistics". In 1893, he wrote the book Handbuch für Untersuchungsrichter (Handbook for Examining Magistrates), which was the first comprehensive treatise describing the application of scientific disciplines-such as medicine, psychology, chemistry, and physics-to criminal investigation. His work laid the foundation of modern forensic science.

Presumptive evidence is evidence that is accepted as true and sufficient until it is disproved or rebutted by other stronger evidence.

It is not conclusive in itself but creates a presumption of fact unless challenged. For example, the possession of stolen goods soon after theft is presumptive evidence of theft, unless explained otherwise.

Section 304A of the Indian Penal Code (IPC) deals with "causing death by negligence". It applies when a person causes the death of another by a rash or negligent act, not amounting to culpable homicide.

Road accident deaths are generally punishable under this section, carrying imprisonment of up to two years, or fine, or both.

When investigators suspect that a surface (such as carpet, wood, or soil) might have been exposed to gasoline or another accelerant, they collect a control sample of the same surface material from an uncontaminated area.

This is called substrate control. It helps in distinguishing whether the chemical detected came from the accelerant or the material itself.

A. Correct - Cheiloscopy is the study of lip prints for human identification.
B. Correct - Lip prints can indicate the point of direct contact between a suspect's lips and an object.
C. Incorrect - It was not described by Leone Lattes in 1915; he was known for work in serology (blood groups).
D. Correct - Cheiloscopy was first described by R. Fischer in 1902.
E. Correct - Lip prints can serve as useful evidence for reconstructing events.
Thus, the correct set is A, B, D, and E.

Animal hairs differ from human hairs in several key microscopic characteristics. They typically have a less developed cortex (A) compared to humans, making their shaft structure distinct.

The medulla in animals is continuous and often patterned (C), unlike in human hair where it is fragmented or absent.

The medullary index is usually greater than 0.5 (D) in animals, while in humans it is less than 0.33.

Options B and E are not correct, since animal hairs do not usually have small irregular cuticle margins (they are more variable), and their shaft diameter generally differs from the human range of 50-150 microns.

A. Liver Mortis → II. Postmortem Hypostasis: After death, blood settles in the dependent parts of the body, causing discoloration (lividity).

B. Cadaveric Spasm → IV. Instantaneous Rigor: This is a rare phenomenon where ertain muscles stiffen immediately at the time of death, bypassing normal rigor mortis.

C. Algor Mortis → I. Postmortem Cooling: The body gradually cools after death, following predictable patterns depending on environment.

D. Rigor Mortis → III. Postmortem Stiffening: The stiffening of muscles that develops within 2-6 hours of death.

In crime scene photography, a linear scale (like a ruler or forensic measurement scale) is placed beside the object to show its actual size and allow accurate comparison later. This ensures that photos can be used as reliable forensic evidence in court.

Infrared (IR) spectrometry works on the principle that different materials absorb infrared radiation at unique frequencies, producing distinctive spectra characteristic to each substance.

This "molecular fingerprinting" makes IR spectrometry especially useful for identifying unknown compounds in forensic analysis.

In chromatography, when a non-polar compound interacts with a non-polar stationary phase, the main governing interactions are weak intermolecular Van der Waals forces. These dispersion forces explain the retention and separation of compounds in non-polar phases