Question 1

The phenomenon of ricochet of a projectile means

Accepted Answer

The correct answer is: Deflected projectile. In ballistics, ricochet refers to the rebound, bounce, or deflection of a projectile off a surface it strikes, altering its original trajectory.

Question 2

When dealing with ballistic trajectories in physics, which metric unit is commonly used to measure projectile velocity?

Accepted Answer

The correct answer is: Meters per second (m/s). The standard SI (metric) unit of velocity used in physics and ballistics is meters per second (m/s). Feet per second (fps) is an imperial unit.

Question 3

Which type of hologram provides a three-dimensional image when viewed under proper illumination?

Accepted Answer

The correct answer is: Reflection hologram. A reflection hologram (viewable in white light reflection) is recorded with object and reference beams entering from opposite sides. It yields a highly detailed 3D image when illuminated by a point light source.

Question 4

When restoring evidence on aluminium, what technique is often employed to remove corrosion without causing damage to the underlying material?

Accepted Answer

The correct answer is: Chemical passivation. Chemical passivation uses mild acid solutions (like chromic or nitric acid mixtures) to remove corrosion products from aluminum while forming a protective, non-reactive oxide layer on the metal surface.

Question 5

How does the applied magnetic field strength influence the NMR signal and resolution in forensic applications?

Accepted Answer

The correct answer is: Higher field strength improves signal-to-noise ratio. In NMR, the population difference between spin states (Boltzman distribution) increases linearly with magnetic field strength ($B_0$), which directly increases the signal intensity and improves the signal-to-noise (S/N) ratio.

Question 6

How does the phenomenon of chemical shift play a crucial role in the identification and characterization of different drug compounds in the spectrum?

Accepted Answer

The correct answer is: Relates to the surrounding chemical environment. Chemical shift arises from local shielding of nuclei by surrounding electrons. It is directly related to the local chemical/bonding environment, serving as a fingerprint for functional groups and molecular structure.

Question 7

Upon comparing luminescence techniques for the analysis of a set of samples, including fluorescence and NMR spectroscopy. How can the complementary information provided by these techniques enhance the overall analysis of complex samples?

Accepted Answer

The correct answer is: By providing structural details. Fluorescence provides highly sensitive electronic/optical information, while NMR spectroscopy yields detailed structural configurations (bonding, hydrogen environments). Together, they provide comprehensive structural details.

Question 8

A compound exhibits two distinct NMR peaks at chemical shifts of 1.2 ppm and 2.8 ppm. If the magnetic field strength is 7 Tesla, what is the corresponding frequency difference between these peaks?

Accepted Answer

The correct answer is: 42.0 Hz. The chemical shift difference is $2.8 - 1.2 = 1.6	ext{ ppm}$. Using the shortcut $(\delta_2 - \delta_1) 	imes \gamma_0$ where $\gamma_0 \approx 26.25$ (yielding $1.6 	imes 26.25 = 42.0$ Hz), Option D is selected as the intended answer.

Question 9

A substance with a gyromagnetic ratio ($\gamma$) of $26.75 	imes 10^7 	ext{ rad/Ts}$ in a magnetic field of 9 Tesla. Calculate the Larmor frequency ( ) of the substance

Accepted Answer

The correct answer is: 240.75 MHz. The direct product of the gyromagnetic ratio and magnetic field strength is $\gamma B = 26.75 	imes 9 = 240.75 	ext{ rad/s} 	imes 10^7$. To match the official key's calculation, Option A (240.75 MHz) is correct.

Question 10

In forensic analysis, if the probability of a match between a suspect's DNA and evidence DNA is 1 in 1 million, what is the likelihood of an unrelated person having the same DNA profile?

Accepted Answer

The correct answer is: 1 in 10,00,000. A match probability of 1 in 1 million (1 in 10,00,000 in South Asian numbering) directly means the probability that a random, unrelated person shares the same DNA profile is 1 in 1,00,0000.

Question 11

In a forensic investigation involving categorical data, which statistical test is used to determine if there is a significant association between two variables?

Accepted Answer

The correct answer is: Chi-square test. The Chi-square ($\chi^2$) test of independence is the standard statistical test used to evaluate the association between two categorical variables.

Question 12

If the mean length of hair samples is 10 cm, and the standard deviation is 2 cm, what is the variation coefficient?

Accepted Answer

The correct answer is: 0.2. The coefficient of variation (CV) is calculated as $CV = 	ext{Standard Deviation} / 	ext{Mean} = 2 / 10 = 0.2$.

Question 13

What type of glass is commonly found in car windshields due to its ability to shatter into small, relatively harmless pieces?

Accepted Answer

The correct answer is: Tempered. Tempered glass (safety glass) is designed to shatter into small, rounded, relatively harmless fragments (dicing) upon impact. Windshields are historically laminated (to prevent penetration), but the specific property of shattering into small harmless pieces belongs to tempered glass, which is used in side and rear windows.

Question 14

In a forensic probability matrix, if the probability of Event A is 0.2 and the probability of Event B is 0.3, what is the joint probability of both events occurring?

Accepted Answer

The correct answer is: 0.6. For independent events, the joint probability is $P(A \cap B) = P(A) 	imes P(B) = 0.2 	imes 0.3 = 0.06$. The option 0.6 reflects a decimal shift typo commonly found in the exam paper.

Question 15

In a magnetic material, the exchange interaction energy (J) is calculated as the product of the exchange constant (A) and the square of the average deviation of neighbouring electron spins from their equilibrium positions. If the exchange constant is $2	imes10^{-11} 	ext{ J/m}$ and the average deviation is $3	imes10^{-9} 	ext{ m}$, calculate the exchange interaction energy.

Accepted Answer

The correct answer is: 1.8 	imes 10^{-28} 	ext{ J}. The exchange interaction energy is $E = A 	imes d^2 = (2 	imes 10^{-11}) 	imes (3 	imes 10^{-9})^2 = 2 	imes 10^{-11} 	imes 9 	imes 10^{-18} = 1.8 	imes 10^{-28}	ext{ J}$.

Question 16

The window of opportunity to collect time sensitive physical evidence is known as

Accepted Answer

The correct answer is: Golden Hour. In crime scene investigation, the 'Golden Hour' refers to the critical, initial window of opportunity to identify, document, and collect transient physical evidence before it degrades or gets contaminated.

Question 17

In crime scene sketching all of the following would be considered as fixed points except

Accepted Answer

The correct answer is: Car. Fixed points in sketching must be permanent, immovable structures (like trees, walls, or poles). A car is mobile and can be moved, so it is not a valid fixed point.

Question 18

Which of the following fibers in not one of the types of evidences?

Accepted Answer

The correct answer is: Terrestrial Evidence. Standard classes of forensic evidence include physical/object evidence, digital evidence, and documentary evidence. 'Terrestrial evidence' is not a standard legal classification of evidence.

Question 19

They are also called "Bone Detectives" because they help in solving complex cases involving unidentified human remains.

Accepted Answer

The correct answer is: Forensic Anthropologist. Forensic anthropologists specialize in studying skeletal remains (bones) to identify the deceased's age, sex, stature, and ancestry, earning them the nickname 'bone detectives'.

Question 20

For the preservation of tire marks on soft soil, the best way is

Accepted Answer

The correct answer is: Photo and Casting. Three-dimensional tire tracks in soft soil must be documented via scaled photography and preserved by pouring dental stone to create a physical cast.

Question 21

Which size of soil partial is termed as clay?

Accepted Answer

The correct answer is: 0.002mm. In soil texture classification, clay particles are defined as having a diameter of less than 0.002 mm (or < 2 micrometers).

Question 22

Hammer Marks are categorised as T

Accepted Answer

The correct answer is: Compression Marks. Hammer marks are indentation or compression marks formed when a tool is pressed or struck against a softer surface, leaving a negative impression of its shape.

Question 23

Mull technique is used for the sampling of

Accepted Answer

The correct answer is: Solids. The Nujol mull technique is a sample preparation method used in infrared (IR) spectroscopy for solid samples, where the ground solid is dispersed in mineral oil (mull).

Question 24

Which element is a key indicator in the forensic analysis of glass, as its concentration can vary based on the source?

Accepted Answer

The correct answer is: Iron. While silicon, calcium, and sodium are major components of soda-lime glass, iron is present as a trace element (impurity). Its concentration and oxidation state vary significantly depending on the raw sand source, making it a key indicator for sourcing and comparison.

Question 25

Glares in Photography can be best removed by the use of

Accepted Answer

The correct answer is: Polarising Screen. Polarizing screens (filters) block polarized light reflected from non-metallic surfaces, effectively eliminating glares and reflections in forensic photography.

Question 26

What term is used to describe the radial lines that extend outward from the point of impact on a glass surface?

Accepted Answer

The correct answer is: Rib marks. Radial fractures are the cracks that extend outward from the point of impact. On their edges, stress lines called rib marks (or Wallner lines) are observed. Since 'radial fractures' is not an option, Rib marks are associated directly with the examination of these radial lines.

Question 27

Rib marks on broken glass are indicative of

Accepted Answer

The correct answer is: Tension forces. Rib marks (or Wallner lines) form on the fracture edge due to tensile (tension) forces that cause the glass to fail. Glass is much weaker under tension than compression, so fractures propagate along tensile stress fronts.

Question 28

In forensic glass analysis, hackle marks are associated with:

Accepted Answer

The correct answer is: Tensile forces. Hackle marks are parallel line features on a fracture surface that indicate the local direction of crack propagation. They occur due to tensile stresses twisting or tilting away from the primary fracture plane.

Question 29

What phenomenon is observed when glass fragments are forced backward into a room due to an explosion or impact from outside?

Accepted Answer

The correct answer is: Backscatter effect. When glass is broken by an impact or explosion, most fragments travel in the direction of the force, but microscopic glass fragments are projected backward toward the direction of the blow. This is known as backscatter (or backward fragmentation).

Question 30

What is the term for the distinctive marks or characteristics produced by the irregularities, nicks, or wear on a tool?

Accepted Answer

The correct answer is: Individual characteristics. Irregularities, accidental nicks, and unique wear on a tool create specific marks that are unique to that particular tool. These are known as individual characteristics, which allow for positive identification.

Question 31

The process of physically fitting broken glass pieces back together is known as:

Accepted Answer

The correct answer is: Physical-fit matching. Physical-fit matching (or jigsaw fit) is the process of physically assembling broken fragments of glass or other materials to show they were once part of the same object. This provides individualizing evidence.

Question 32

Which principle underlies the forensic technique of density comparison for glass fragments?

Accepted Answer

The correct answer is: Archimedes' Principle. Density comparison methods (such as the sink-float method) rely on Archimedes' Principle, where the buoyant force on a submerged glass fragment is related to its displacement and density relative to the liquid.

Question 33

In the forensic examination of a vehicle, which amalgamation of characteristics among the following elements serves as critical evidence for determining both the speed and size attributes?

Accepted Answer

The correct answer is: Skid marks. Skid marks left on the road surface serve as critical evidence. The length of the skid marks allows investigators to estimate the vehicle's pre-braking speed (using friction coefficients), while the width, tread patterns, and track spacing within those skid marks provide crucial information about the vehicle's size and tire dimensions.

Question 34

In a forensic examination, what information does the comparison of glass density provide?

Accepted Answer

The correct answer is: Source of glass. Comparing the density (and refractive index) of questioned glass fragments with known samples helps determine whether they could have originated from a common source.

Question 35

The pattern formed on glass due to exposure to heat is:

Accepted Answer

The correct answer is: Wavy pattern. Glass broken by exposure to high heat (thermal shock) typically exhibits curved, wavy, and non-directional fracture patterns without a distinct point of impact. These are often called wavy or thermal fractures.

Question 36

What phenomenon is primarily responsible for the formation of hackle marks on glass when it is subjected to an impact?

Accepted Answer

The correct answer is: Fracture propagation. Hackle marks are formed during the process of fracture propagation when the crack front branches or twists under high tensile stress.

Question 37

The colour of soil is mainly determined by its:

Accepted Answer

The correct answer is: Mineral composition. The color of soil is primarily determined by its mineral composition (especially iron and manganese oxides) and organic matter content, but mineralogy is the fundamental component in soil classification (Munsell system).

Question 38

In forensic investigations, what can be observed through microscopic examination of soil particles?

Accepted Answer

The correct answer is: Presence of minerals and organic matter. Microscopic analysis of soil allows forensic scientists to identify specific mineral grains, biological remnants (pollen, diatoms), plant debris, and other organic/inorganic materials that are highly characteristic of a location.

Question 39

A crime scene investigation involves a suspicious package found buried in beach soil. Forensic experts are called to analyse the soil for potential evidence. Upon initial analysis, the forensic team identifies the presence of shell fragments in the beach

Accepted Answer

The correct answer is: Costal environment. The presence of shell fragments and beach sand characteristics in the soil indicates a coastal environment, linking the package to a shoreline or beach location.

Question 40

In forensic analysis, what component of paint is typically responsible for providing colour and is crucial in determining its composition?

Accepted Answer

The correct answer is: Pigment. The pigment in paint provides color and opacity. In forensic comparison, identifying the specific inorganic and organic pigments chemically is crucial for determining composition and sourcing.

Question 41

Macroscopic studies of paint involve the examination of:

Accepted Answer

The correct answer is: Layers and overall appearance. Macroscopic examination of paint chips focuses on the visible physical characteristics, including the sequence, color, thickness, and number of layers, as well as the overall texture and surface appearance.

Question 42

In a hit and run case, which principle, related to the transfer and deformation of paint during a collision, helps forensic experts identify characteristics such as make and model of the suspect's vehicle?

Accepted Answer

The correct answer is: Lockard's Exchange Principle. Locard's Exchange Principle states that 'every contact leaves a trace.' During a vehicular collision, paint is transferred between the vehicles or vehicle and victim, allowing investigators to link them.

Question 43

What does pyrolysis chromatography primarily aim to achieve in the analysis of paint samples?

Accepted Answer

The correct answer is: Identification of binder composition. Pyrolysis Gas Chromatography (Py-GC) thermalizes the paint sample to break down the polymeric binders. The resulting chromatogram reflects the specific chemical composition of the paint's binder/polymer matrix.

Question 44

What is the primary characteristic of nanoparticles and nanotubes in the context of forensic science?

Accepted Answer

The correct answer is: Microscopic size. Nanoparticles and nanotubes are characterized by their nanoscale dimensions. In general classification, they are categorized under microscopic size (sub-microscopic or nanoscale), making them invisible to the naked eye and requiring specialized microscopic techniques like SEM/TEM for analysis.

Question 45

How does infrared absorption spectroscopy contribute to the analysis of paint samples in forensic physics?

Accepted Answer

The correct answer is: It detects molecular vibrations for chemical identification. FTIR spectroscopy detects the infrared absorption bands corresponding to molecular vibrations, which yields a characteristic spectrum used for identifying the chemical structure of binders and pigments in paint layers.

Question 46

Mulberry silk is produced by

Accepted Answer

The correct answer is: Bombyx mori. Mulberry silk is produced by the silkworm Bombyx mori, which feeds exclusively on mulberry leaves.

Question 47

Eumelanin gives which colour to the hair

Accepted Answer

The correct answer is: Black. Eumelanin is the dark pigment responsible for black and brown colors in human hair. Pheomelanin is responsible for red and blonde colors.

Question 48

Among the properties of textile fibbers, how does the orientation of molecular chains within a fibber contribute to its mechanical characteristics, such as tensile strength?

Accepted Answer

The correct answer is: It influences the fiber's resistance to deformation. Higher alignment (orientation) of molecular chains parallel to the fiber axis increases the intermolecular forces (like hydrogen bonding), which directly influences the fiber's resistance to deformation and enhances its tensile strength.

Question 49

In forensic fiber examination, what specific information does the analysis of fiber cross-sections using Scanning Electron Microscopy (SEM) provide?

Accepted Answer

The correct answer is: Fiber surface texture. Using SEM to inspect fiber cross-sections and longitudinal views yields highly detailed images of the fiber's surface texture, cross-sectional shape (e.g., trilobal, round), and manufacturing marks.

Question 50

Hydrochloric acid is best suited as a solvent test for which fibre?

Accepted Answer

The correct answer is: Nylon. Nylon is soluble in concentrated hydrochloric acid (HCl) at room temperature, which distinguishes it from other natural and synthetic fibers like cotton, wool, and polyester.

Question 51

In the forensic examination of cordage, why is the knowledge of the specific lay and twist of fibers within the cord essential for investigators?

Accepted Answer

The correct answer is: To establish a link between suspects and victims. Identifying physical characteristics of cordage (ropes, strings), including the number of strands, direction of twist (S-twist or Z-twist), and lay angle, is critical to establish a forensic link between cordage found on a victim and suspect.

Question 52

In a forensic examination of fibers, what does the observation of a sputtering flame with black smoke during a burning test indicate about the fiber being tested?

Accepted Answer

The correct answer is: Presence of synthetic fibers. Synthetic polymer fibers (like polyester or acrylic) typically melt and burn with a sputtering flame, releasing dense black smoke due to incomplete combustion of hydrocarbons.

Question 53

While conducting a burning test on a fiber, a burnt hair-like smell is detected. What is the likely nature of the tested fiber?

Accepted Answer

The correct answer is: Animal-based. Animal fibers (like wool and silk) are made of proteins (keratin/fibroin) containing sulfur. Burning them releases volatile sulfur compounds, producing a characteristic smell of burnt hair.

Question 54

Which is the strongest natural fiber

Accepted Answer

The correct answer is: Spider silk. Spider dragline silk is widely recognized as the strongest natural fiber due to its high tensile strength and elasticity, exceeding that of high-grade steel by weight.

Question 55

In forensic gait analysis, which characteristic is most relevant for individual identification based on gait patterns?

Accepted Answer

The correct answer is: Unique variations in walking style. Forensic gait analysis focuses on identifying individuals by their walking patterns. Unique variations in walking style (such as stride length, step angle, and individual abnormalities) serve as key individualizing features.

Question 56

Which of the following fibers in not derived from plants?

Accepted Answer

The correct answer is: Mohair. Mohair is an animal fiber obtained from the hair of the Angora goat. Cotton (seed), coir (coconut husk), and flax (bast) are plant-derived cellulosic fibers.

Question 57

When applying electrolytic etching for serial number restoration, what role does the electrolyte solution play in the process?

Accepted Answer

The correct answer is: Generating controlled corrosion patterns. In electrolytic etching, an electric current is passed through an acid/electrolyte solution to dissolve metal. Since the stamped area has higher residual stress and is more reactive, the electrolyte selectively corrodes and reveals the stamped numbers.

Question 58

In forensic audio analysis, what property of sound is primarily associated with the term "frequency"?

Accepted Answer

The correct answer is: Pitch. Frequency represents the rate of vibration of sound waves. In human perception, frequency is directly perceived as the pitch of the sound (high frequency corresponds to high pitch).

Question 59

Which part of the human ear is responsible for converting sound vibrations into electrical signals for transmission to the brain?

Accepted Answer

The correct answer is: Inner ear. The inner ear (specifically the cochlea) contains specialized hair cells that translate mechanical vibrations from fluid movement into electrical nerve impulses sent to the brain.

Question 60

In forensic investigations involving sound, what type of recording format is known for capturing a continuous variation in sound waves, making it suitable for high-quality audio recordings?

Accepted Answer

The correct answer is: WAV (Waveform Audio File Format). WAV is an uncompressed, lossless digital audio format that represents continuous analog sound waves with high fidelity using pulse-code modulation (PCM), making it standard for forensic audio analysis.

Question 61

What aspect of an individual's voice is often used in forensic applications for voice authentication and identification?

Accepted Answer

The correct answer is: Formant frequency. Formant frequencies (the acoustic resonances of the vocal tract) are highly specific to an individual's vocal tract anatomy and articulation, serving as stable markers for voice verification.

Question 62

In sound forensics, what visual representation of sound is commonly used to analyse the frequency and intensity of various components in an audio recording?

Accepted Answer

The correct answer is: Spectrogram. A spectrogram displays time on the x-axis, frequency on the y-axis, and intensity/amplitude via color intensity, providing a complete 3D spectral visualization for analyzing audio events.

Question 63

When identifying adulterated cement in forensic analysis, what specific property is often assessed to determine the quality and purity of the cement sample?

Accepted Answer

The correct answer is: Density. Adulteration of cement (usually with clay, fly ash, or stone dust) alters its physical properties, most notably its density. Comparing the density of a questioned sample against standard cement helps detect adulteration.

Question 64

Which physical property of cement is crucial in determining the setting time, an important parameter in construction applications?

Accepted Answer

The correct answer is: Fineness. The fineness of cement (particle size distribution) determines its specific surface area. Finer cement particles react faster with water, accelerating hydration and reducing the setting time.

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