2014 June NTA UGC-NET / JRF Previous Year Solved Question Paper, Part -2

Answer: C. Verifying the composition of an aspirin tablet before it leaves the factory.

Explanation: Verifying the composition of an aspirin tablet before it leaves the factory is a quality control measure and not a forensic application of science. Forensic science deals with the application of scientific methods and techniques to investigate crimes and legal matters. The other options – identifying drugs in a traffic stop, identifying human remains, and determining the cause of an amusement park accident – are all examples of forensic applications of science.

Answer: C. Death in road accident

Explanation: A police inquest is typically conducted in cases of suspicious or unnatural deaths, such as deaths in prison, deaths by drowning, or deaths involving firearms. Road accidents, unless involving suspicious circumstances, do not usually require a police inquest. The primary purpose of a police inquest is to determine the cause and circumstances surrounding a death when foul play is suspected.

Answer: A. (iv) (i) (ii) (iii)

Explanation: In forensic science, the chain of custody refers to the documentation and tracking of evidence from the crime scene to the courtroom, ensuring its integrity and preventing tampering. Accreditation ensures the quality and competence of a forensic laboratory or facility. Certification validates the expertise and skills of individual forensic examiners. Inceptive evidence is the initial evidence that determines whether a crime has been committed, setting the stage for further investigation.

Answer: B. Sec. 304 B

Explanation: In the Indian Penal Code, Section 304 B specifically deals with dowry deaths. This section was introduced in 1986 to combat the growing problem of dowry-related violence and deaths in India. According to this section, if a woman dies within seven years of her marriage and it is shown that she was subjected to cruelty or harassment by her husband or his relatives in connection with a demand for dowry, the death is considered a “dowry death,” and the husband or relative is presumed to have caused the death.

Answer: B. Locard

Explanation: The principle “every contact leaves a trace” is known as Locard’s Exchange Principle, named after Dr. Edmond Locard, a pioneer in forensic science. This principle states that whenever two objects come into contact, there is an exchange of material between them. In a crime scene, this means that the perpetrator will bring something into the scene and leave with something from the scene. This principle forms the basis for the collection and analysis of trace evidence in forensic investigations.

Answer: C. NABL

Explanation: In India, the accreditation of forensic science laboratories is carried out by the National Accreditation Board for Testing and Calibration Laboratories (NABL). NABL is an autonomous body under the Department of Science and Technology, Government of India. It assesses and accredits laboratories based on international standards (ISO/IEC 17025) to ensure the quality and competence of the laboratories. Accreditation by NABL is a recognition of a laboratory’s technical competence and adherence to quality management systems.

Answer: D. Paul Kirk

Explanation: The book “Crime Investigation” was written by Paul Leland Kirk, an American biochemist and forensic scientist. Kirk is considered one of the pioneers in the field of criminalistics. His book, first published in 1953, was one of the earliest comprehensive texts on crime scene investigation techniques and the application of physical evidence in solving crimes. The book covered topics such as fingerprints, blood analysis, ballistics, document examination, and trace evidence.

Answer: B. Rays of different colours do not have a common focus

Explanation: Chromatic observation, more commonly known as chromatic aberration, is a type of optical distortion where a lens fails to focus all colors to the same point. This occurs because lenses have a different refractive index for different wavelengths of light. As a result, rays of different colors are focused at slightly different points, leading to color fringing or a blurry appearance, especially at high-contrast edges. Achromatic lenses are designed to minimize this effect by bringing two wavelengths (typically red and blue) into focus in the same plane.

Answer: B. Polarising Microscope

Explanation: A Nicol prism, invented by William Nicol in 1828, is a type of polarizer used in polarizing microscopes. It is made from a calcite crystal that has been cut at a specific angle and then rejoined with Canada balsam cement. When unpolarized light enters the prism, it is split into two polarized rays. One of these rays (the ordinary ray) is totally internally reflected at the balsam layer and is deflected to the side of the prism, while the other ray (the extraordinary ray) passes through, resulting in plane-polarized light. Polarizing microscopes are used to study birefringent materials, stresses in transparent materials, and for identifying minerals and crystals.

Answer: A. A chain of dynodes

Explanation: A photomultiplier tube (PMT) is a highly sensitive detector of light in the ultraviolet, visible, and near-infrared ranges. It consists of a photocathode, which emits electrons when struck by light, followed by a series of dynodes, which are electrodes that serve to amplify the electron signal. Each dynode is maintained at a higher positive voltage than the previous one. When the electrons emitted by the photocathode strike the first dynode, multiple secondary electrons are emitted, and these, in turn, strike the next dynode, causing further electron multiplication. This process continues for each dynode, resulting in a cascade effect that greatly amplifies the original signal. PMTs are used in a wide variety of applications, including spectroscopy, medical imaging, and high-energy physics experiments.

Answer: A. (a) and (b) are correct

Explanation: Absorption filters are optical filters that selectively absorb certain wavelengths of light while transmitting others. Gelatin filters and colored glass filters are commonly used as absorption filters. Gelatin filters are made by dissolving organic dyes in gelatin and then casting the mixture into thin sheets. Different dyes are used to create filters that absorb different parts of the spectrum. Colored glass filters, such as those made from cobalt blue glass or copper ruby glass, also selectively absorb certain wavelengths due to the presence of metal ions in the glass. Metal films and cardboard, on the other hand, are not typically used as absorption filters in optical applications.

Answer: C. Expansion of gas

Explanation: A Golay cell, also known as a Golay detector or pneumatic detector, is a type of infrared detector that operates by measuring the expansion of a gas. It consists of a sealed chamber filled with a gas, typically xenon, and a flexible membrane that forms one wall of the chamber. When infrared radiation enters the chamber through an infrared-transparent window, it heats the gas, causing it to expand. This expansion deflects the membrane, and this deflection is measured using optical or capacitive methods. Golay cells are known for their high sensitivity and wide spectral response, making them useful for infrared spectroscopy and thermal imaging applications.

Answer: D. Chemical shift

Explanation: Chemical shift is a key concept in nuclear magnetic resonance (NMR) spectroscopy. It refers to the resonant frequency of a nuclear spin relative to a standard in a magnetic field. The electron cloud around a nucleus shields it from the external magnetic field, altering the effective magnetic field at the nucleus. This shielding effect varies depending on the chemical environment of the nucleus, leading to different resonant frequencies or “chemical shifts” for nuclei in different chemical environments. Chemical shifts provide detailed information about the molecular structure and are used to identify and characterize compounds in NMR spectroscopy.

Answer: C. Both (A) and (B) are correct.

Explanation: Stereoisomers are isomeric molecules that have the same molecular formula and sequence of bonded atoms but differ in the three-dimensional orientations of their atoms in space. Enantiomers, a type of stereoisomer, are mirror images of each other that are non-superimposable. They have identical physical properties, including mass spectra, but may have different biological activities. Diastereomers, another type of stereoisomer, are not mirror images and may have different physical properties. However, they too will have identical mass spectra because mass spectrometry does not differentiate between stereoisomers as it fragments the molecules and measures the mass-to-charge ratios of the resulting ions.

Answer: D. All of the above

Explanation: Thin Layer Chromatography (TLC) is a simple, quick, and inexpensive analytical technique used to separate the components of a mixture. It has several advantages: (1) The equipment is simple, consisting of a glass or plastic plate coated with a thin layer of adsorbent material (stationary phase), a developing chamber, and a UV lamp or chemical spray for visualization. (2) The development time is short, typically a few minutes, as the solvent (mobile phase) travels quickly through the thin adsorbent layer. (3) There is a wide choice of stationary phases, including silica gel, alumina, and cellulose, which can be modified to improve separation. Additionally, TLC requires only small amounts of sample, and multiple samples can be run simultaneously on a single plate.

Answer: A. Both (A) and (R) are correct.

Explanation: In High-Performance Liquid Chromatography (HPLC), it is essential to degas the solvents before use. Dissolved gases in the solvents can lead to the formation of bubbles in the system, which can cause several problems. These bubbles can interfere with the proper functioning of the pump, leading to inconsistent flow rates and pressures. They can also affect the detector’s response, causing baseline noise and drift. Moreover, bubbles in the column can disrupt the packing of the stationary phase, leading to poor separation and reduced column efficiency. Therefore, degassing the solvents improves the overall performance and reliability of the HPLC system.

Answer: C. Freeze-etching

Explanation: Freeze-etching is a sample preparation technique used in electron microscopy, particularly in scanning electron microscopy (SEM), to preserve and visualize the structures of biological specimens. In this method, the sample is rapidly frozen, typically using liquid nitrogen or high-pressure freezing, to immobilize the water in the cells and prevent the formation of ice crystals that can damage the cellular structures. The frozen sample is then fractured and coated with a thin layer of metal (usually platinum) to create a replica of the fractured surface. The biological material is then removed, leaving behind the metal replica, which is viewed in the SEM. Freeze-etching allows for the visualization of fine structural details, including the interior of cells and membranes.

Answer: B. Thermostat

Explanation: In HPLC (High-Performance Liquid Chromatography), the temperature of the column is a critical parameter that can affect the separation of the analytes. Temperature control is important because it influences the viscosity of the mobile phase, the solubility of the analytes, and the kinetics of the interactions between the analytes and the stationary phase. A thermostat, also known as a column oven, is used to regulate and maintain a constant temperature in the HPLC column. The thermostat encloses the column and uses heating elements and sensors to precisely control the temperature. Most modern HPLC systems have built-in thermostats that can be programmed to maintain a specific temperature or to apply temperature gradients during the chromatographic run.

Answer: D. All of the above

Explanation: Blood type inheritance follows Mendelian genetics. Blood types A and B are codominant, while O is recessive. If one parent has blood type A (genotype AO or AA) and the other has blood type B (genotype BO or BB), their children can have blood type A (if they inherit A from one parent and O from the other), blood type B (if they inherit B from one parent and O from the other), blood type AB (if they inherit A from one parent and B from the other), or blood type O (if they inherit O from both parents). Therefore, if the parents are A and B, their children could have any of the four blood types, depending on which alleles they inherit.

Answer: A. Lombroso

Explanation: Cesare Lombroso, an Italian criminologist and physician, is often credited with being one of the first to attempt to use physiological measures to detect deception in the late 19th century. Lombroso believed that certain physical characteristics, such as facial asymmetry or large jaws, were indicative of criminal behavior. While his theories of criminal anthropology and the “born criminal” are now largely discredited, his idea of using physiological measures to detect deception was influential in the development of later polygraph techniques. However, it was John Augustus Larson, a Canadian police officer and physiologist, who developed the first modern polygraph in 1921, which measured continuous changes in blood pressure, heart rate, and respiration.

Answer: C. (iii) (iv) (ii) (i)

Explanation: In forensic biology, various tests and stains are used to identify specific biological fluids and cells:

(a) Alpha-amylase is an enzyme found in high concentrations in saliva. The alpha-amylase test is used to identify the presence of saliva in forensic samples.

(b) Nuclear Fast Red is a histological stain used to counterstain cell nuclei. In forensic contexts, it is often used to stain sperm cells, as it stains the nuclei of these cells a distinct red color.

(c) Brentamine Fast Blue B is a dye used in the acid phosphatase test, which is a presumptive test for the presence of seminal fluid. Acid phosphatase is an enzyme found in high levels in semen.

(d) Thrombocytes, also known as platelets, are blood cells involved in the clotting process. They are not directly tested for in forensic contexts but are a component of blood.

Answer: B. Immune system

Explanation: Leukocytes, also known as white blood cells, are a crucial component of the body’s immune system. They help protect the body against infectious agents and foreign substances. There are several types of leukocytes, each with specific functions: neutrophils, eosinophils, and basophils (granulocytes); lymphocytes (T cells and B cells); and monocytes. These cells work together to provide both innate and adaptive immunity. They can engulf and destroy pathogens, produce antibodies, release inflammatory mediators, and coordinate the overall immune response. In contrast, red blood cells (erythrocytes) are primarily responsible for transporting oxygen to cells and carrying carbon dioxide away from cells.

Answer: C. (b) and (d)

Explanation: Seminal fluid contains a variety of proteins that can be used as markers for the identification of semen in forensic investigations. Two of these protein markers are peptidase C and sperm diaphorase.

Peptidase C, also known as prostate-specific antigen (PSA), is a serine protease produced by the prostate gland and is a major component of seminal fluid. It is used as a marker for the presence of semen and can be detected using immunoassay techniques.

Sperm diaphorase, also known as diaphorase-4, is an enzyme specific to the midpiece of the sperm cell. It is used as a confirmatory test for the presence of sperm cells in forensic samples.Amylase and transferrin, while present in other body fluids (saliva and blood, respectively), are not considered specific markers for semen.

Answer: A. Both (A) and (R) are correct.

Explanation: Saliva plays a crucial role in the initial stages of digestion. It is secreted by the salivary glands in the mouth and contains several enzymes, including alpha-amylase (also known as ptyalin). Alpha-amylase is responsible for the breakdown of starch, a complex carbohydrate, into simpler sugars such as maltose and dextrin. This process, known as oral digestion, begins in the mouth as soon as food is mixed with saliva. The partially digested food then passes through the esophagus to the stomach, where further digestion takes place. In addition to its digestive function, saliva also lubricates the food, making it easier to swallow, and helps to maintain oral pH and prevent tooth decay.

Answer: A. Both (A) and (R) are correct.

Explanation: Blood is a non-Newtonian fluid, meaning its viscosity (resistance to flow) changes with the amount of force applied to it. At low shear rates, blood is more viscous than water, primarily due to the presence of cells (particularly red blood cells) and proteins in the blood. The higher viscosity of blood results in slower flow compared to water under similar conditions. This is important for the proper functioning of the circulatory system, as it helps maintain blood pressure and allows for efficient exchange of nutrients and waste products in the capillaries. However, at high shear rates (such as in large arteries), blood viscosity decreases, and it can flow more easily. This shear-thinning property of blood is called the non-Newtonian behavior.

Answer: C. Periodic Acid Schiff

Explanation: Presumptive tests for blood are used in forensic investigations to quickly screen for the possible presence of blood in a sample. These tests are based on the peroxidase-like activity of hemoglobin, which catalyzes the oxidation of certain chromogenic substrates, producing a visible color change. Leucomalachite Green (LMG), phenolphthalein (Kastle-Meyer test), and tetramethylbenzidine (TMB) are all common presumptive tests for blood. However, the Periodic Acid Schiff (PAS) test is not a presumptive test for blood. Instead, it is a staining method used in histology and pathology to detect polysaccharides, mucins, and glycoproteins in tissues. The PAS test involves the oxidation of vicinal diols in these compounds by periodic acid, followed by the reaction with Schiff’s reagent to produce a purple-magenta color.

Answer: B. 0.78 to 0.82

Explanation: Kerosene is a combustible hydrocarbon liquid widely used as a fuel in aviation (jet fuel), heating, and lighting. It is a mixture of hydrocarbons, typically containing 10 to 16 carbon atoms per molecule, obtained from the fractional distillation of petroleum between 150°C and 275°C. The relative density (or specific gravity) of a substance is the ratio of its density to the density of a reference substance, usually water for liquids. The relative density of kerosene at 15°C typically falls in the range of 0.78 to 0.82. This property is important for quality control, as it affects the fuel’s performance and energy content. Kerosene with a relative density outside this range may contain impurities or be mixed with other substances, which could affect its safety and efficiency when used as a fuel.

Answer: D. Prussian Blue test

Explanation: Hydrocyanic acid, also known as hydrogen cyanide (HCN), is a highly toxic chemical compound. In forensic toxicology, the Prussian Blue test is used to detect the presence of cyanide in biological samples. The test relies on the formation of a bright blue complex, called Prussian Blue, when ferrous ions (Fe2+) react with cyanide ions (CN-) in the presence of ferric ions (Fe3+). The reaction involves the oxidation of ferrous ions to ferric ions by cyanide, followed by the precipitation of ferric ferrocyanide (Prussian Blue). The intensity of the blue color is proportional to the concentration of cyanide in the sample. This test is sensitive and specific for cyanide, making it useful in cases of suspected cyanide poisoning. Other tests mentioned, such as the Ferric Chloride test, Libermann’s test, and Nessler’s reagent test, are used for different purposes and do not specifically detect cyanide.

Answer: C. (iii) (i) (iv) (ii)

Explanation: In forensic toxicology, it is important to understand the active principles in various poisonous plants:

(a) Nux Vomica (Strychnos nux-vomica) contains strychnine and brucine, which are potent neurotoxins that cause convulsions and respiratory failure.

(b) Opium, derived from the opium poppy (Papaver somniferum), contains several alkaloids, including morphine, codeine, and papaverine. These compounds have analgesic and sedative effects but can cause respiratory depression and addiction.

(c) Dhatura (Datura stramonium) contains atropine, scopolamine, and hyoscyamine, which are anticholinergic compounds that cause delirium, hallucinations, and tachycardia.

(d) Abrus Precatories (Abrus precatorius), also known as jequirity or rosary pea, contains abrin, a potent toxin that inhibits protein synthesis and can cause severe gastrointestinal symptoms and organ damage.

Answer: C. Dilirium

Explanation: Dhatura (Datura stramonium), also known as jimson weed or devil’s snare, is a poisonous plant that contains tropane alkaloids, primarily atropine, scopolamine, and hyoscyamine. These compounds are potent anticholinergics, meaning they block the action of acetylcholine, a neurotransmitter involved in various physiological processes. Datura poisoning is characterized by a range of symptoms, but one of the most prominent is delirium. Delirium is a state of acute confusion, characterized by disorientation, hallucinations, agitation, and altered consciousness. Other symptoms of Datura poisoning include dilated pupils, dry mouth, flushed skin, tachycardia, urinary retention, and in severe cases, coma and respiratory depression. While convulsions, paralysis, and coma can occur in some cases of Datura poisoning, delirium remains the most characteristic and frequently observed symptom.

Answer: A. Chloroform

Explanation: The Fujiwara test, also known as the Fujiwara reaction, is a qualitative test used to detect the presence of chloroform (CHCl3) and other trihalomethanes in a sample. The test is based on the reaction of chloroform with pyridine (C5H5N) and sodium hydroxide (NaOH), which produces a red-colored complex. The reaction mechanism involves the deprotonation of chloroform by the strong base (NaOH) to form a carbene intermediate, which then reacts with pyridine to form the colored complex. The Fujiwara test is sensitive and can detect chloroform at concentrations as low as 1 ppm. It is commonly used in forensic toxicology to screen for chloroform exposure or poisoning, as chloroform is a toxic substance that can cause central nervous system depression, liver and kidney damage, and even death at high doses. The test is not specific to chloroform and can give positive results with other trihalomethanes, such as bromoform and iodoform.

Answer: C. LD 50

Explanation: In toxicology, LD50 (Lethal Dose 50) is a standard measure of the toxicity of a substance. It is defined as the dose of a substance that is lethal to 50% of the test population under specified conditions. The LD50 is usually determined experimentally in animal studies, typically using rodents such as rats or mice. The test population is administered various doses of the substance, and the mortality rate is observed. The LD50 is then calculated using statistical methods. A lower LD50 value indicates a higher toxicity, as less of the substance is needed to cause death in half of the population. LD50 values are used to compare the relative toxicities of different substances and to establish safety guidelines for exposure. However, it is important to note that LD50 values do not provide information about other toxic effects that may occur at lower doses and that the values may differ between species. ED50 (Effective Dose 50), on the other hand, refers to the dose of a drug that produces a therapeutic response in 50% of the population.

Answer: C. Organophosphorous compounds

Explanation: Sludge syndrome, also known as cholinergic crisis, is a set of symptoms caused by the excessive stimulation of cholinergic receptors due to the inhibition of acetylcholinesterase (AChE) enzyme. This syndrome is most commonly associated with poisoning by organophosphorus compounds, which are widely used as pesticides and nerve agents. These compounds irreversibly inhibit AChE, leading to the accumulation of acetylcholine at the synapses and overstimulation of cholinergic receptors. Symptoms of sludge syndrome include salivation, lacrimation, urination, defecation, gastrointestinal distress, and emesis (SLUDGE). Other symptoms may include miosis, bronchospasm, bradycardia, and muscle fasciculations. Treatment involves the administration of atropine to counteract the muscarinic effects and pralidoxime to reactivate the inhibited AChE. Organochloro compounds, carbamates, and barbiturates have different mechanisms of action and do not typically cause the sludge syndrome.

Answer: B. Forensic Ballistics

Explanation: “Hatcher’s Notebook” is a classic reference book in the field of forensic ballistics, written by Major General Julian S. Hatcher, a renowned firearms expert. The book, first published in 1935, is a comprehensive guide to the identification, examination, and interpretation of firearms, ammunition, and related evidence in forensic investigations. It covers a wide range of topics, including the history and development of firearms, ballistics theory, bullet and cartridge case identification, gunshot wounds, and the examination of firearm-related evidence. The book is known for its detailed illustrations and practical approach, making it a valuable resource for forensic scientists, firearms examiners, and law enforcement personnel. While it is not primarily focused on forensic toxicology, forensic medicine, or forensic psychiatry, it does touch on some aspects of these fields as they relate to firearm injuries and deaths.

Answer: C. 219 ft/sec

Explanation: The terminal velocity of a falling object is the maximum speed it can reach when falling through a fluid (such as air) due to the resistance of the medium. For a falling bullet, the terminal velocity depends on factors such as the bullet’s mass, shape, and surface area, as well as the density and viscosity of the air. A 9mm bullet, which is a common handgun caliber, typically has a terminal velocity of around 219 feet per second (67 meters per second) when falling from a sufficient height. This velocity is much lower than the muzzle velocity of a fired 9mm bullet, which can exceed 1,000 feet per second. Nonetheless, a falling bullet at terminal velocity can still cause serious injury or death, especially if it strikes a sensitive area like the head or neck. This is why it is important to always handle firearms safely and to be aware of the potential dangers of falling bullets, even in celebratory gunfire situations.

Answer: A. (iii) (iv) (i) (ii)

Explanation: In forensic ballistics and explosives analysis, it is crucial to understand the characteristics and uses of different types of propellants and explosives:

(a) Cordite is a smokeless propellant used in firearms ammunition. It is made from nitrocellulose and nitroglycerin, often with added stabilizers and plasticizers.

(b) PETN (pentaerythritol tetranitrate) is a powerful secondary high explosive. It is sensitive to shock and friction and is often used in detonators and detonating cords.

(c) Lead azide is a primary high explosive used as an initiator or detonator. It is highly sensitive and can be easily detonated by heat, friction, or impact.

(d) Lesmoke powder is a type of semi-smokeless powder used in some firearms ammunition. It produces less smoke than traditional black powder but more than modern smokeless powders.

Answer: B. Macy

Explanation: In the context of firearm manufacturing, several terms are associated with prominent gun makers and designs. Luger refers to a series of semi-automatic pistols designed by Georg Luger, most famously the Luger P08, which was used by German forces during World War I and II. Smith and Wesson (not Weisen) is a major American firearms manufacturer known for its revolvers and pistols. Colt is another iconic American firearms brand, founded by Samuel Colt, known for its revolvers, pistols, and rifles, including the famous Colt Single Action Army (also known as the Peacemaker). However, Macy is not a term related to firearms manufacturing. Macy’s is an American department store chain, not associated with the production of guns. In forensic firearm examination, it is essential to be familiar with the correct terminology and the history of major gun manufacturers to properly identify and analyze firearms-related evidence.

Answer: C. With an anvil in it

Explanation: A primer is a small, sensitive charge of an explosive mixture used to ignite the propellant in a firearm cartridge. There are two main types of primers: Boxer and Berdan. Boxer primers, named after their inventor Edward Boxer, are used in most centerfire ammunition made in the United States. A key feature of Boxer primers is that they contain an integral anvil as part of the primer assembly. The anvil is a small metal protrusion that provides a rigid surface for the primer compound to be crushed against when struck by the firing pin. This crushing action initiates the combustion of the primer, which in turn ignites the main propellant charge. The integral anvil in Boxer primers makes them easier to manufacture and more convenient for reloading spent cartridges, as the anvil is replaced along with the primer. In contrast, Berdan primers, named after American inventor Hiram Berdan, have the anvil as a separate component that is part of the cartridge case. Berdan primers are more common in European and Asian ammunition.

Answer: A. The volume of gas produced decreases with the burning of powder.

Explanation: In forensic ballistics, the burning characteristics of propellants are crucial in determining the internal ballistics of a firearm. Propellants can be classified based on their burning rate profiles, which describe how the surface area of the propellant grains changes as they burn. Degressive powders, also known as regressive powders, are designed to have a burning rate that decreases as the powder burns. This means that the volume of gas produced by the burning powder decreases over time. Degressive powders typically have a geometry where the surface area of the grains decreases as the powder burns, such as grains with a spherical or flattened spherical shape. The decreasing gas production of degressive powders can help to control the pressure curve in the gun barrel, reducing peak pressures and potentially improving accuracy and barrel life. In contrast, progressive powders have a burning rate that increases as the powder burns, while neutral powders have a relatively constant burning rate.

Answer: B. Trichosiderins

Explanation: Hair color is determined by the presence and ratios of different pigments in the hair shaft. The two main types of pigments are eumelanin, which is responsible for black and brown colors, and pheomelanin, which produces red and yellow colors. However, in true blond and red hair, the primary pigments are not melanins but rather trichosiderins. Trichosiderins are a class of pigments that include compounds like phaeomelanic pigments and trichorhoidin. These pigments are thought to be derived from the amino acid tryptophan and are chemically distinct from the more common melanins. The exact biosynthetic pathway and the genetic factors controlling the production of trichosiderins are not yet fully understood. In forensic hair analysis, understanding the pigmentation of hair can provide valuable information about an individual’s physical characteristics and can help in the identification of unknown persons or in linking a suspect to a crime scene.

Answer: B. Cortical fusi

Explanation: The cortex is the thickest and most substantial layer of the hair shaft, making up about 90% of the hair’s total weight. It consists of elongated, keratinized cells that are tightly packed together. Interspersed among these cells are air spaces known as cortical fusi. Cortical fusi are small, irregular, air-filled cavities that are found along the length of the hair shaft. They are formed during the keratinization process of the cortical cells, possibly due to the degeneration of the cell nuclei or the incomplete fusion of the cells. The presence and distribution of cortical fusi can vary among different individuals and can be affected by factors such as age, hair type, and certain hair disorders. In forensic hair analysis, the examination of cortical fusi can provide information about the health and integrity of the hair, as well as assist in the comparison of hair samples from different sources.

Answer: B. Human hair

Explanation: In human biology and forensic hair analysis, hair is classified into different types based on its characteristics and developmental stages. Primordial hair is the first hair type to appear during fetal development, around the 9th week of gestation. It is fine, unpigmented, and covers the entire body of the fetus. Lanugo hair is the second type to develop, replacing the primordial hair around the 20th week of gestation. Lanugo hair is also fine, unpigmented, and usually shed before or shortly after birth. Vellus hair is the fine, short, and often unpigmented hair that covers most of the body after birth and throughout life. It is commonly referred to as “peach fuzz.” Terminal hair is the longer, thicker, and often pigmented hair that develops during puberty and is found on the scalp, beard, pubic region, and other androgen-dependent areas. The examination of these different hair types can be relevant in forensic investigations involving infants, children, or adults, as well as in cases where the developmental stage or body area of origin of a hair sample is in question.

Answer: C. (iii) (i) (iv) (ii)

Explanation: In forensic fiber analysis, it is essential to understand the sources and characteristics of different types of fibers:

(a) Sisal is a natural vegetable fiber extracted from the leaves of the sisal plant (Agave sisalana). It is often used in ropes, twines, and carpets.

(b) Mohair is a natural animal fiber obtained from the hair of the Angora goat. It is known for its softness, shine, and durability.

(c) Teflon is a synthetic fluorocarbon polymer known for its non-stick and heat-resistant properties. It is used in various applications, including cookware and industrial coatings.

(d) Rayon is a regenerated cellulose fiber made from purified cellulose, usually derived from wood pulp or cotton linters. It is a versatile man-made fiber used in clothing, upholstery, and other textiles.

Answer: B. Plaster of Paris

Explanation: In forensic investigations, the proper collection and preservation of fiber evidence from a crime scene is crucial for subsequent analysis and comparison. Several methods are commonly used for this purpose:

(a) Adhesive tape is a simple and effective method for collecting fiber evidence. The tape is pressed onto the surface containing the fibers, and then the tape is lifted, picking up the fibers in the process. The tape can then be sealed in a clear plastic bag for transport and analysis.

(c) Picking fibers by forceps is another method, especially useful when fibers are large or visible. The fibers are carefully grasped with the forceps and transferred to a suitable packaging material, such as a paper fold or an evidence bag.

(d) Vacuuming is a method used to collect fibers and other trace evidence from larger areas. A filtered vacuum cleaner is used to suction the fibers, which are then trapped in the filter for later analysis.

However, (b) Plaster of Paris is not a common method for collecting fiber evidence. Plaster of Paris is a calcium sulfate hemihydrate powder that hardens when mixed with water, and it is typically used for casting impressions of footprints, tire tracks, or tool marks. It is not suitable for collecting fibers as it would not effectively pick up or preserve the fibers.

Answer: C. Sodalime silica

Explanation: In forensic glass analysis, it is important to understand the different types of glass and their compositions, as this information can help in sourcing and comparing glass evidence. Flat window pane glass, the most common type of glass used in windows and doors, is typically made from soda-lime silica glass. Soda-lime silica glass is composed of silica (SiO2), soda ash (Na2CO3), and lime (CaO), along with small amounts of other additives such as magnesium oxide, aluminum oxide, and potassium oxide. The soda and lime act as fluxes, lowering the melting temperature of the silica and making the glass easier to shape. Soda-lime silica glass is relatively inexpensive, durable, and has good optical clarity, making it suitable for windows and other architectural applications. Pyrex and borosilicate glass are different types of glass with distinct compositions and properties. Pyrex is a brand name for a type of borosilicate glass that is known for its heat resistance and low thermal expansion, making it suitable for laboratory glassware and cookware. Borosilicate glass contains significant amounts of boron trioxide (B2O3) in addition to silica and other components.

Answer: B. Hydrogen Aluminium Silicate

Explanation: In forensic soil analysis, understanding the composition and characteristics of different soil types can help in comparing and sourcing soil evidence. Kaolinite is a common clay mineral found in many soils worldwide. It is the main constituent of kaolin clay, a white, soft, and earthy clay that is widely used in ceramics, paper making, and other industries. Kaolinite has the chemical formula Al2Si2O5(OH)4, which indicates that it is a hydrated aluminum silicate. The mineral is composed of alternating layers of aluminum oxide octahedra and silicon oxide tetrahedra, held together by hydrogen bonds. This layered structure gives kaolinite its characteristic softness and low plasticity. Other minerals mentioned in the choices, such as calcium carbonate (CaCO3), magnesium carbonate (MgCO3), and sodium carbonate (Na2CO3), are not the main constituents of kaolinite clay soil. These minerals can be found in other types of soils or sediments, such as limestone (CaCO3), dolomite (CaMg(CO3)2), and alkali soils (Na2CO3).

Answer: B. Striation tool marks

Explanation: In forensic tool mark analysis, a striagraph is an instrument used for the examination and comparison of striated tool marks. Striated tool marks are created when a tool with a rough surface, such as a file or a saw blade, is dragged across another surface, leaving behind a series of parallel lines or striations. These striations can be unique to the specific tool that created them, based on the microscopic irregularities and wear patterns on the tool’s surface. A striagraph is essentially a specialized microscope that allows for the detailed examination and comparison of striation patterns. It typically consists of a stage for holding the tool mark sample, an illumination system, and a camera or digital imaging system for capturing high-resolution images of the striations. By comparing the striation patterns from a questioned tool mark with those from a known tool, forensic examiners can determine if the marks were made by the same tool. Striagraphs are not typically used for examining punch marks, hackle marks on glass, or skid marks from vehicles, as these types of marks have different characteristics and require other analytical techniques.

Answer: C. Hackle marks

Explanation: In forensic tool mark analysis, tool marks are generally classified into three main types:

(a) Striation marks: These are a series of parallel lines or grooves created when a tool is dragged across a surface, such as when a screwdriver is used to pry open a door or a knife is used to cut through a material. The individual characteristics of the tool, such as its blade edge or tip, can leave unique striation patterns.

(b) Compression marks: These are indentations or impressions left on a surface when a tool is pressed into it, such as when a hammer strikes a surface or a punch is used to create a hole. The shape, size, and depth of the compression mark can be indicative of the specific tool used.

(d) Combination marks: These are tool marks that exhibit both striation and compression characteristics, often resulting from a tool being used in a complex motion or with varying force. An example could be a pair of pliers used to grip and twist a wire, leaving both compression marks from the jaws and striation marks from the twisting motion.

Hackle marks, however, are not a type of tool mark. Hackle marks are a feature commonly observed in fractured glass and other brittle materials. They appear as a series of curved lines or ridges that radiate outward from the point of impact or origin of the fracture. Hackle marks are caused by the rapid propagation of cracks through the material and can provide information about the direction of force and the sequence of fracture events. While hackle marks are important in forensic glass analysis, they are not considered tool marks, as they are not created by the direct action of a tool on a surface.

Answer: A. (a) and (b) are correct.

Explanation: In forensic tool mark analysis, casting is a technique used to create a three-dimensional replica of a tool mark for examination and comparison purposes. The choice of casting material depends on the type of tool mark, the substrate material, and the desired level of detail in the replica. Two of the most suitable materials for casting tool marks are:

(a) Wood’s metal: This is a low-melting-point alloy composed of bismuth, lead, tin, and cadmium. It has a melting point of approximately 70°C, which allows it to be easily melted and poured into the tool mark impression. Wood’s metal provides excellent detail reproduction and is suitable for casting tool marks on both metallic and non-metallic surfaces.

(b) Vinylite: This is a family of thermoplastic resins that includes polyvinyl chloride (PVC) and polyvinyl acetate (PVA). Vinylite casting materials are available in liquid or paste form and can be applied directly to the tool mark surface. They harden at room temperature and provide good detail reproduction, especially for tool marks on non-porous surfaces.

While plaster of Paris and wax can be used for casting in some situations, they have limitations compared to Wood’s metal and Vinylite. Plaster of Paris is porous and may not capture fine details, while wax may not be suitable for casting tool marks on surfaces with high temperatures or rough textures.

Answer: B. 10°

Explanation: In forensic tool mark analysis, the angle at which a tool is held when creating a mark can significantly influence the appearance and characteristics of the resulting mark. When comparing a questioned tool mark with a known standard mark made by the same tool, variations in the tool angle can complicate the matching process. Research has shown that a variation of around 10° in the tool angle can cause significant changes in the striation patterns and individual characteristics of the tool mark. When the angle difference exceeds 10°, the tool marks may appear sufficiently different that they could be mistakenly excluded as a match, even though they were made by the same tool. This is because the angle affects how the tool’s surface irregularities interact with the substrate material and how the striations are formed. To minimize the effect of tool angle variation, forensic examiners often create multiple test marks with the known tool at different angles and compare them with the questioned mark. They may also use advanced imaging techniques and statistical algorithms to quantify the similarity between marks while accounting for reasonable variations in angle. Nonetheless, the 10° threshold serves as a general guideline for the potential influence of tool angle on tool mark matching.

Answer: C. 2.65

Explanation: Quartz is one of the most abundant minerals in the Earth’s crust and is commonly encountered in forensic soil and mineral analysis. The relative density, also known as specific gravity, is a key physical property that can help identify and characterize minerals. The relative density of a substance is the ratio of its density to the density of water at a specified temperature (usually 4°C). For quartz, the relative density is approximately 2.65. This means that quartz is about 2.65 times denser than water. This value is consistent across different varieties of quartz, such as rock crystal, amethyst, and smoky quartz. In forensic contexts, the relative density of quartz can be used to compare and identify soil samples, as well as to distinguish quartz from other minerals with similar appearances but different densities. For example, the relative density of calcite is about 2.71, while that of gypsum is about 2.32. Measuring the relative density, along with other properties such as hardness, cleavage, and optical characteristics, can provide valuable information for forensic soil and mineral analysis.

Answer: C. Common salt

Explanation: Plaster of Paris (calcium sulfate hemihydrate) is a commonly used material for casting footprints and other impression evidence in forensic investigations. When mixed with water, Plaster of Paris undergoes a chemical reaction, forming calcium sulfate dihydrate and hardening into a solid cast. The setting time of Plaster of Paris can be influenced by various factors, such as the water-to-plaster ratio, temperature, and the presence of additives. Common salt (sodium chloride) is known to accelerate the setting process of Plaster of Paris. When salt is added to the Plaster of Paris mixture, it dissolves in the water and dissociates into sodium and chloride ions. These ions interact with the calcium sulfate hemihydrate, promoting the formation of calcium sulfate dihydrate crystals and speeding up the hardening process. The accelerating effect of salt on Plaster of Paris setting can be beneficial in forensic situations where a quick cast is needed, such as when there is a risk of the impression being disturbed or degraded over time. However, the amount of salt added should be controlled, as excessive salt can lead to a weaker and more brittle cast.

Answer: A. Both (A) and (R) are correct.

Explanation: In forensic odontology, the eruption sequence and development of teeth are important factors in estimating the age of an individual, particularly in children and adolescents. However, the use of eruption sequence for age estimation becomes less reliable and applicable beyond the age of 25 years. This is because, by the age of 25, all the permanent teeth have usually erupted into the oral cavity. The typical eruption sequence of permanent teeth is completed by the age of 21 years, with the third molars (wisdom teeth) being the last to erupt, usually between the ages of 17 and 25 years. Once all the permanent teeth have erupted, the eruption sequence no longer provides useful information for age estimation. After the age of 25, forensic odontologists rely on other techniques for age estimation, such as the assessment of tooth wear, periodontal changes, secondary dentin deposition, root transparency, and cementum annulations. These methods, however, are less precise than the eruption sequence and provide age ranges rather than specific ages. Therefore, both the assertion and the reason given in the question are correct. The eruption sequence of teeth is not helpful for age estimation beyond 25 years because all the permanent teeth are expected to have erupted by that age.

Answer: B. Premolar

Explanation: The primary dentition, also known as deciduous or milk teeth, is the first set of teeth that humans develop. The primary dentition consists of 20 teeth in total, with 10 teeth in each jaw. The tooth types present in the primary dentition are:

1. Incisors: There are four incisors in each jaw, two central and two lateral incisors.

2. Canines: There are two canines in each jaw, one on each side.

3. Molars: There are four molars in each jaw, two on each side.

Notably absent from the primary dentition are premolars. Premolars are only present in the permanent dentition, which replaces the primary teeth. In the permanent dentition, there are four premolars in each jaw, two on each side, located between the canines and molars.

The transition from primary to permanent dentition starts around the age of 6 years and is usually completed by the age of 12-13 years, with the exception of the third molars (wisdom teeth). Understanding the differences between primary and permanent dentition is crucial in forensic odontology, as it helps in age estimation, identification of individuals, and distinguishing between adult and child remains in forensic cases.

Answer: B. (i) (ii) (iv) (iii)

Explanation: In forensic anthropology, various methods and techniques are used to estimate different aspects of an individual’s biological profile from skeletal remains:

(a) Stature estimation: Regression equations are commonly used to estimate stature (height) from the measurements of long bones, such as the femur, tibia, and humerus. These equations are based on the statistical relationship between bone lengths and stature in a reference population.

(b) Sex determination: The glabella, which is the prominent bony ridge above the nose and between the eyebrows, is one of the morphological features used in sex determination from the skull. The glabella tends to be more pronounced and robust in males compared to females.

(c) Race estimation: Prognathism, which refers to the forward projection of the jaws, is one of the morphological characteristics used in ancestry or race estimation from the skull. Different populations exhibit varying degrees of prognathism, with some populations having more pronounced prognathism than others.

(d) Age estimation: Gustafson’s method is a dental age estimation technique that assesses the degree of six age-related changes in teeth: attrition, periodontosis, secondary dentin deposition, cementum apposition, root resorption, and root transparency. The method assigns scores to each of these changes and uses a formula to estimate the age based on the total score.

Answer: A. Dental anomaly

Explanation: Microdontia is a dental anomaly characterized by teeth that are smaller than normal in size. It can affect a single tooth or multiple teeth and can occur in both primary and permanent dentition. Microdontia is usually a genetic condition and can be associated with certain syndromes, such as Down syndrome and ectodermal dysplasia. There are three main types of microdontia:

1. True generalized microdontia: All teeth in the dentition are smaller than normal.

2. Relative generalized microdontia: The teeth are normal in size but appear small due to a larger jaw size.

3. Localized microdontia: Only one or a few teeth are smaller than normal, with the most commonly affected tooth being the maxillary lateral incisor.

In forensic odontology, dental anomalies such as microdontia can be useful in the identification of individuals, as they can provide unique and distinctive characteristics that can help distinguish one individual from another. Dental anomalies can also be used to estimate age, as certain anomalies are more prevalent in specific age groups or developmental stages.

Answer: A. Sex

Explanation: The sciatic notch and sub-pubic angle are two morphological features of the pelvis that are commonly used in sex determination from skeletal remains in forensic anthropology.

The sciatic notch is a large notch located on the posterior border of the hip bone, below the posterior inferior iliac spine. In females, the sciatic notch tends to be wider and more shallow, forming a greater angle, while in males, it is usually narrower and deeper, forming a smaller angle. This difference is attributed to the adaptation of the female pelvis for childbirth.

The sub-pubic angle is the angle formed by the two inferior pubic rami at the point where they meet at the pubic symphysis. In females, the sub-pubic angle is generally wider, typically greater than 90 degrees, due to the broader and more circular pelvic outlet. In males, the sub-pubic angle is usually narrower and more acute, typically less than 90 degrees, resulting from a taller and narrower pelvis.

While the sciatic notch and sub-pubic angle are primarily used for sex determination, they are not reliable indicators of age or stature. Age-related changes in the pelvis, such as the fusion of the sacral vertebrae and the development of the pubic symphysis, are used for age estimation. Stature estimation is typically based on the measurements of long bones, such as the femur and tibia, using regression equations specific to different populations.

Answer: A. Portrait Parle

Explanation: Portrait Parle, also known as the “spoken picture” or “verbal portrait,” was a method of criminal identification developed by Alphonse Bertillon, a French police officer and biometrics researcher, in the late 19th century. Bertillon is considered one of the pioneers of anthropometry and the use of physical measurements for human identification.

The Portrait Parle method involved a systematic and standardized description of an individual’s physical characteristics, such as height, build, eye color, hair color, scars, and tattoos. The description also included measurements of various body parts, such as the length and width of the head, the length of the left foot, and the length of the left middle finger. These measurements and descriptions were recorded on a standardized card, known as the Bertillon card, which could be used for identification and comparison purposes.

The Portrait Parle system was one of the first attempts to establish a scientific method of criminal identification based on physical characteristics. It was widely used by law enforcement agencies in Europe and the United States in the late 19th and early 20th centuries, before the adoption of fingerprinting as a more reliable and unique means of identification.

The other options mentioned – Photo-fit, Identity kit, and Skull photo superimposition – are more recent techniques used in forensic identification and were not developed by Bertillon.

Answer: B. Bone

Explanation: Haversian canals, also known as osteonic canals, are microscopic channels found in compact bone tissue. They are a key component of the Haversian system, or osteon, which is the basic structural unit of compact bone. Haversian canals are named after Clopton Havers, an English physician who first described them in the 17th century.

Haversian canals run parallel to the long axis of the bone and contain blood vessels, nerves, and loose connective tissue. They are surrounded by concentric layers of bone matrix, called lamellae, which are formed by osteoblasts. The Haversian canals interconnect with each other and with the outer surface of the bone through transverse or oblique channels called Volkmann’s canals.

The Haversian system is responsible for the blood supply, innervation, and metabolism of compact bone tissue. It allows for the exchange of nutrients and waste products between the blood vessels and the bone cells (osteocytes) embedded in the mineralized matrix. The presence of Haversian canals and the organization of the osteons contribute to the strength and mechanical properties of compact bone.

In forensic contexts, the analysis of Haversian canals and osteons can provide valuable information about the microstructure and remodeling of bone. The density and organization of Haversian systems can vary with age, health status, and mechanical stress, and can be used to estimate the age of skeletal remains or to identify pathological conditions affecting the bone.

Answer: B. Sphenoid

Explanation: The sphenoid bone, one of the eight bones that form the cranium, is also known as the “winged bone” due to its unique shape. It is located at the base of the skull, wedged between the frontal, temporal, and occipital bones. The sphenoid bone is a complex and irregularly shaped bone that plays a crucial role in the anatomy of the skull and the cranial cavity.

The most distinctive feature of the sphenoid bone is its greater wings, which extend laterally from the central body of the bone. These wings form a significant portion of the middle cranial fossa and the lateral walls of the orbit. The lesser wings of the sphenoid bone extend anteriorly and form part of the roof of the orbit.

The sphenoid bone also contains several important foramina and fissures that allow for the passage of nerves and blood vessels. These include the optic foramen, which transmits the optic nerve and ophthalmic artery; the superior orbital fissure, which transmits cranial nerves III, IV, and VI, and the ophthalmic division of cranial nerve V; and the foramen rotundum, which transmits the maxillary division of cranial nerve V.

In forensic anthropology, the sphenoid bone can be useful in the estimation of age and sex from skeletal remains. The development and fusion of the various parts of the sphenoid bone occur at different stages of growth and can provide information about the age of the individual. Additionally, certain features of the sphenoid bone, such as the size and shape of the sella turcica (a saddle-shaped depression that houses the pituitary gland), can exhibit sexual dimorphism and aid in sex determination.

Answer: C. A loop formation completely filled with ink

Explanation: In the field of forensic handwriting analysis, a blind loop refers to a specific characteristic of loop formations in handwriting where the loop is completely filled with ink, making it appear solid and dark. This feature is often observed in the lowercase letters ‘e,’ ‘l,’ and ‘b,’ as well as in some uppercase letters like ‘L’ and ‘E.’

A blind loop is formed when the writer’s pen or writing instrument does not leave the paper while forming the loop, resulting in a continuous flow of ink that fills the entire loop space. This is in contrast to an open loop, where the pen leaves the paper, creating a hollow space within the loop.

The presence or absence of blind loops in handwriting can be a useful characteristic for handwriting comparison and identification. Handwriting experts consider the consistency, shape, and size of blind loops when analyzing questioned documents and comparing them with known writing samples.

Blind loops can be a habitual feature of an individual’s handwriting, reflecting their writing style, speed, and pen pressure. However, the presence or absence of blind loops alone is not sufficient for a conclusive identification, as handwriting analysis involves the examination of multiple features and characteristics in combination.

It is important to note that while blind loops are a complete loop formation filled with ink, they are not the same as an incomplete loop formation (option A) or a partially filled loop formation (option D).

Answer: B. Non Flammable Ninhydrin

Explanation: In the context of fingerprint detection and enhancement, NFN stands for “Non Flammable Ninhydrin.” Ninhydrin is a chemical compound widely used in forensic science for the visualization of latent fingerprints on porous surfaces such as paper, cardboard, and untreated wood.

Traditionally, ninhydrin solutions used for fingerprint development were prepared using highly flammable solvents such as acetone or petroleum ether. These solvents posed safety risks due to their flammability and potential for ignition. To address this issue, non-flammable ninhydrin (NFN) formulations were developed.

NFN solutions typically use less flammable or non-flammable solvents, such as HFE-7100 (hydrofluoroether) or HCFC-141b (hydrochlorofluorocarbon), as the carrier for ninhydrin. These solvents have a higher flash point and lower volatility compared to traditional solvents, making them safer to use and store in forensic laboratories.

When a porous surface containing latent fingerprints is treated with an NFN solution, the ninhydrin reacts with the amino acids present in the fingerprint residue. This reaction produces a dark purple color known as Ruhemann’s purple, which makes the fingerprint visible and suitable for further analysis and comparison.

The use of non-flammable ninhydrin has become a standard practice in many forensic laboratories worldwide, as it provides a safer alternative to traditional ninhydrin formulations without compromising the effectiveness of fingerprint development.

It is important to note that NFN does not stand for “Non Fluorescent Ninhydrin” (option A), “Non Fuming Ninhydrin” (option C), or “Non Fading Ninhydrin” (option D), as these terms do not accurately describe the primary characteristic of the NFN formulation.

Answer: A. Sulphur analog of Ninhydrin

Explanation: 5-MTN Hemiketal, also known as 5-methylthioninhydrin hemiketal, is a chemical compound used for the development of latent fingerprints on porous surfaces. It is a sulfur analog of ninhydrin, meaning that it has a similar structure to ninhydrin but with a sulfur atom replacing an oxygen atom.

Ninhydrin is a widely used reagent in forensic science for detecting latent fingerprints. It reacts with the amino acids present in fingerprint residue, producing a dark purple color known as Ruhemann’s purple. However, ninhydrin has some limitations, such as the need for heat and humidity for optimal development and the lack of fluorescence for enhanced visualization.

5-MTN Hemiketal was developed as an alternative to ninhydrin, offering several advantages. When 5-MTN Hemiketal reacts with the amino acids in fingerprint residue, it produces a product that is highly fluorescent under certain lighting conditions. This fluorescence allows for better visualization and contrast of the developed fingerprints, especially on dark or multicolored surfaces.

Moreover, 5-MTN Hemiketal does not require additional heat or humidity for optimal development, making it more convenient and faster to use compared to ninhydrin. It can develop latent fingerprints at room temperature, which is particularly useful in field settings or when processing a large number of samples.

The fact that 5-MTN Hemiketal is a sulfur analog of ninhydrin, rather than an alkyl (option B), aryl (option C), or alkoxy (option D) analog, is significant because the presence of the sulfur atom contributes to its unique properties and advantages in fingerprint development.

Answer: A. A ball as the writing tip

Explanation: Ball point pens and gel pens are two common types of writing instruments used in daily life and often encountered in forensic document examination. While these pens have some differences in their ink composition and writing characteristics, they share a key similarity in their design: the presence of a ball as the writing tip.

Both ball point pens and gel pens use a small, spherical ball, usually made of brass, steel, or tungsten carbide, as the writing tip. This ball is housed in a socket at the tip of the pen and is free to rotate. As the pen is moved across the paper, the ball rolls and picks up ink from the ink reservoir inside the pen barrel. The ink is then deposited onto the paper through the motion of the ball, creating the written line.

The ball tip design allows for a smooth and consistent flow of ink, as the ball constantly rotates and maintains contact with both the ink reservoir and the paper surface. This mechanism is essential for the proper functioning of both ball point pens and gel pens.

However, there are notable differences between the two pen types. Ball point pens typically use a thick, oil-based ink that dries quickly and is less likely to smudge. Gel pens, on the other hand, use a water-based gel ink that is thicker and more pigmented than traditional liquid inks. Gel ink tends to produce smoother, more vibrant lines and is available in a wide range of colors.

In forensic document examination, understanding the similarities and differences between ball point pens and gel pens can be important for ink analysis, dating of documents, and the identification of alterations or forgeries.

Answer: B. Graphite

Explanation: Despite their name, modern lead pencils do not actually contain lead. The writing core of a lead pencil is primarily composed of graphite, a form of carbon known for its softness and ability to leave a dark mark on paper.

Graphite has been used as a writing material since the 16th century, when a large deposit of pure graphite was discovered in Borrowdale, England. Initially, it was thought to be a form of lead, hence the misnomer “lead pencil.” However, it was later identified as a distinct substance, and the name “graphite” was coined in 1789 by German mineralogist Abraham Gottlob Werner, derived from the Greek word “graphein,” meaning “to write.”

In a modern lead pencil, the graphite core is typically mixed with clay and wax, which help to bind the graphite particles and control the hardness and darkness of the pencil’s mark. The proportion of graphite to clay determines the pencil’s grade, with higher graphite content resulting in a softer, darker line (e.g., “B” grades) and higher clay content producing a harder, lighter line (e.g., “H” grades).

The graphite-clay mixture is then encased in a protective wooden sheath, usually made from cedar, which makes the pencil easy to hold and sharpen. Some pencils may also have an eraser attached to one end for correcting errors.

In forensic document examination, understanding the composition and characteristics of lead pencils can be important for analyzing and comparing handwritten entries, as well as for detecting alterations or erasures made with pencils.

Answer: B. Temporary nature

Explanation: In the field of forensic document examination, typewritten documents often contain various defects or peculiarities that can be used to identify or individualize a specific typewriter. These defects can be classified into two main categories: permanent defects and transitory defects.

Transitory defects, also known as temporary defects, are irregularities in the typewritten text that are not consistent throughout the document and may appear or disappear over time. These defects are typically caused by temporary conditions or issues with the typewriter mechanism, ribbon, or typing elements.

Examples of transitory defects in typewritten documents include:

1. Fading or light impressions: This can occur when the typewriter ribbon is near the end of its life or not properly inked, resulting in inconsistent or faint text.

2. Misalignment or shifting of characters: If the typewriter’s alignment mechanisms are loose or worn, the typed characters may appear slightly misaligned or shifted, but this may not be consistent throughout the document.

3. Ink smears or blobs: These can be caused by overinking, dirt, or debris on the typewriter elements, and may appear intermittently in the text.

4. Incorrect or missing characters: If the typewriter keys are sticking or not functioning properly, some characters may be printed incorrectly or omitted, but this may not occur consistently.

Transitory defects are considered temporary because they can change or disappear over time as the typewriter’s condition changes, such as when the ribbon is replaced, the machine is cleaned, or the alignment is adjusted. In contrast, permanent defects, such as damaged type faces or bent type bars, will appear consistently throughout the document and are more reliable for individualizing a specific typewriter.

In forensic document examination, both permanent and transitory defects are analyzed to help determine the source of a typed document, to compare questioned documents with known exemplars, or to establish the sequence or timing of document creation.

Answer: B. Guided signature

Explanation: In forensic handwriting analysis, a guided signature refers to a signature that is written with the physical assistance or guidance of another person. This type of signature is often encountered in cases involving elderly individuals, people with physical disabilities, or those who are illiterate and require help in signing documents.

In a guided signature, the person providing the assistance typically holds the hand or arm of the signer and helps them move the writing instrument to form the signature. The degree of guidance can vary, from gentle support to more substantial control over the writing motion.

Guided signatures can be problematic in forensic handwriting analysis because they may not accurately represent the signer’s natural handwriting characteristics. The influence of the guiding person can affect the speed, pressure, and overall appearance of the signature, making it difficult to compare with the signer’s genuine signatures.

When examining a questioned signature that is suspected to be guided, forensic handwriting experts look for signs of hesitation, tremors, or unusual pen pressure that may indicate the involvement of another person. They may also compare the questioned signature with known samples of the signer’s unguided writing to assess the degree of deviation.

It is important to distinguish guided signatures from other types of non-genuine signatures:

1. Copied signatures (option A) are those that are written by someone else attempting to imitate the genuine signature, usually freehand and from memory.

2. Traced signatures (option C) are created by directly tracing over a genuine signature, either on a transparent overlay or by using a light box.

3. Simulated signatures (option D) are freehand imitations of a genuine signature, often produced by someone familiar with the signer’s handwriting style.

In legal contexts, guided signatures may raise questions about the signer’s intent, capacity, and the validity of the signed document. Forensic handwriting experts can provide valuable insights into the nature and extent of the guidance provided and its potential implications for the authenticity of the signature.

Answer: A. A will written by the signatory himself

Explanation: A holographic will, also known as a handwritten will or olographic will, is a testamentary document that is written entirely in the handwriting of the person making the will (the testator). This type of will is distinct from other forms of wills, such as typed wills or wills prepared by an attorney.

The key characteristics of a holographic will are:

1. Handwritten: The will must be written by hand by the testator. It cannot be typed, printed, or written by someone else on behalf of the testator.

2. Entirely in the testator’s handwriting: The material provisions of the will, including the distribution of assets and the appointment of an executor, must be in the testator’s own handwriting. The will may not contain any preprinted or typed language.

3. Signed by the testator: The will must be signed by the testator, typically at the end of the document, to indicate their intent to make the will legally binding.

4. Dated: Although not always required, it is generally recommended that a holographic will include the date on which it was written and signed.

Holographic wills are recognized as valid in some jurisdictions, provided they meet the necessary legal requirements. However, the specific rules governing holographic wills can vary between countries and states.

In forensic document examination, holographic wills may be scrutinized to determine their authenticity and to verify that they were indeed written and signed by the purported testator. Handwriting analysis techniques can be used to compare the handwriting in the will with known samples of the testator’s writing to establish authorship.

It is important to note that options B and C, which describe wills written by someone other than the signatory or wills that are neither written nor signed by the same person, do not fit the definition of a holographic will. These scenarios would typically involve other types of wills, such as typed wills or wills executed with the assistance of witnesses or legal professionals.

Answer: B. No Carbon Required

Explanation: In the context of document examination, NCR stands for “No Carbon Required.” It refers to a type of paper used for creating multiple copies of a document simultaneously without the need for carbon paper.

NCR paper, also known as carbonless copy paper or pressure-sensitive paper, consists of two or more sheets of paper that are coated with special chemicals. The back of the top sheet is coated with microcapsules containing colorless dye precursors, while the front of the bottom sheet is coated with a reactive clay layer.

When pressure is applied to the top sheet, such as by writing or typing, the microcapsules on the back of the top sheet rupture and release the colorless dye precursors. These precursors react with the clay layer on the front of the bottom sheet, producing a colored copy of the written or typed content. This process is repeated for each subsequent sheet in the NCR set, allowing for the creation of multiple copies without the need for carbon paper.

NCR paper is commonly used in various business and legal contexts, such as contracts, invoices, receipts, and forms, where multiple copies of a document are required for record-keeping or distribution purposes.

Answer: C. Sebaceous glands

Explanation: Sebaceous glands are absent on the palmar (palm) and plantar (sole) surfaces of the hands and feet. These glands are typically found associated with hair follicles and are responsible for producing sebum, an oily substance that helps lubricate and waterproof the skin and hair. The palms and soles lack hair follicles and, consequently, do not have sebaceous glands. However, these areas do have eccrine (sweat) glands and apocrine glands (which secrete a different type of sweat). The presence of eccrine glands on the palms and soles contributes to the formation of friction ridge patterns on these surfaces, which are essential in the study of fingerprints and palmprints.

Answer: B. Respiration, blood pressure, pulse rate, galvanic skin response

Explanation: In lie detection instrument tests, commonly known as polygraph tests, the following physiological observations are typically taken into consideration: respiration (breathing rate and patterns), blood pressure, pulse rate (heart rate), and galvanic skin response (changes in skin conductivity due to sweating). These measurements are recorded and analyzed by the polygraph instrument while the subject is asked a series of questions. Changes in these physiological responses are believed to be indicators of stress or deception, although the accuracy and reliability of polygraph tests have been debated.

Answer: A. Trauma

Explanation: Artificial bruises, also known as self-inflicted or simulated bruises, are intentionally created by individuals for various reasons, such as seeking attention or falsely accusing someone of abuse. True bruises, on the other hand, are caused by trauma or injury, such as blunt force or compression. Therefore, the presence of trauma is a characteristic that is shared by both true and artificial bruises, and it cannot be used as a distinguishing factor. Other characteristics that can help differentiate artificial bruises from true bruises include the presence of itching (artificial bruises may cause itching due to the method used to create them), irregular shapes (true bruises often have more natural and irregular shapes), and color (artificial bruises may appear darker or more uniform in color compared to true bruises).

Answer: D. All of the above

Explanation: Forensic entomology, the study of insects and their interactions with the legal system, has various applications in crime investigations. It can help in cases of suspected death by analyzing the insect activity on the deceased, providing valuable information about the time of death and potential movement of the body. Forensic entomologists can also assist in cases involving the disturbance of crime scenes by examining insect evidence and determining if and when the scene was disturbed. Additionally, forensic entomology can contribute to drug analysis by detecting the presence of drugs or toxins in insect specimens collected from the crime scene or the body. Therefore, forensic entomology can aid in all the mentioned scenarios: suspected death, disturbance of crime scene, and drug analysis.

Answer: D. Psychopath

Explanation: Idiot, imbecile, and moron are outdated and offensive terms that were previously used to classify different levels of intellectual disability or mental deficiency. These terms are no longer used in clinical or professional settings due to their stigmatizing nature. However, psychopathy is not a type of mental deficiency; it is a personality disorder characterized by a lack of empathy, remorse, and antisocial behavior. Psychopaths typically have average or above-average intelligence and do not necessarily have intellectual disabilities. Therefore, the term “psychopath” does not fit into the category of mental deficiency types, making it the correct answer for this question.

Answer: A. Both (A) and (R) are correct.

Explanation: Forensic taphonomy is the study of the processes and environmental factors that affect the decomposition and preservation of human remains after death. It involves the examination of the history and circumstances surrounding the body from the time of death until its discovery. The reason (R) correctly states that forensic taphonomy includes the study of weathering of bones, scavenging and disarticulation (separation of body parts), and the transportation of dead bodies. By analyzing these factors, forensic taphonomists can gain insights into the circumstances surrounding the death, such as the approximate time since death, potential cause of death, and any disturbances or movements of the body. Therefore, both the assertion (A) and the reason (R) are correct statements about forensic taphonomy.