Shahid Posted July 3 Share Posted July 3 Prepare the PMC Paid Practice Tests Series 2021 with our comprehensive past paper and explanation guide. Gain valuable insights into the exam format, question types, and essential topics covered. Our detailed explanations will help you understand the reasoning behind each answer, allowing you to strengthen your knowledge and improve your performance. Get a head start on your exam preparation and increase your chances of success with our PMC Paid Practice Tests Series 2021 past paper and explanation resource. QUESTION: Choose the correct spelling of the word:A. SomethingB. SomthingC. Sumthing D. Sumthin EXPLANATIONSomething is the correct spelling. QUESTION: Choose the correct sentence:A. Does your train leaves before eight oclock?B. Do your train leaves before eight oclock?C. Does your train leaves before eight oclock D. Does your train leaves before eight oclock? EXPLANATIONWe use do/does or is/are as question words when we want to ask yes/no questions. We use does and is with third-person singular pronouns (he, she, it) and with singular noun forms. We use do and are with other personal pronouns (you, we, they) and with plural noun forms. oclock is an abbreviation of of the clock. QUESTION: Did I say anything to make you angry?A. DeclarativeB. lmperative C. InterrogativeD. Exclamatory EXPLANATIONThe sentence is questioning. The question mark at the end of the sentence and the tone it is asked in indicates the person is inquiring about something. QUESTION: Thank you. Youve been very _______ through this time.A. IdealB. CruelC. KindD. Glad EXPLANATIONThe person would be thankful if they had received kind behaviour. QUESTION: Either my mother or my father _____________ coming to the meeting.A. IsB. AreC. Are beingD. Has EXPLANATIONWhen deciding whether to use is or are, look at whether the noun is plural or singular. If the noun is singular, use is. If it is plural or there is more than one noun, use are. QUESTION: I borrowed ________ pencil from your pile of pencils and pens.A. AB. AnC. TheD. No article is required EXPLANATIONA/an and the are articles. They are types of determiners and they go before a noun. Use βaβ before words that start with a consonant sound and βanβ before words that start with a vowel sound. QUESTION: Choose the correct sentence:A. He always loved sweets, chocolates, biscuits, and cakes.B. He always loved, sweets, chocolates, biscuits and cakes.C. He always loved sweets. chocolates, biscuits, and cakes.D. He always loved sweets, chocolates biscuits and cakes. EXPLANATIONWhen making a list, commas are the most common way to separate one list item from the next. The final two items in the list are usually separated by and or or, which is preceded by a comma. Option C is wrong because there is a full stop instead of a comma in the list. Option B is wrong because there should not be a comma after loved, as loved is not an item in the list. Option D is wrong because there is no comma between chocolates and biscuits. Thus Option A is correct. QUESTION: Select the nearest correct meaning of the word: Unburdened.A. HinderedB. ExtortC. FreeD. Encumbered EXPLANATIONUnburdened means to relieve (someone) of something that is causing them anxiety or distress. QUESTION: We still havent come __________ with an interesting theme for the advertising campaign.A. OnB. InC. UpD. Down EXPLANATIONCome up is an expression used to say: to produce, especially in dealing with a problem or challenge. QUESTION: _________ people know the town better than old Jake here. A. Only fewB. The fewC. Only the fewD. Few EXPLANATIONThere is no need for any preposition before few. Prepositions are always used to indicate the relationship of a noun or phrase to something else. When using a preposition, you must always have the subject and verb before it, and follow it with a noun. QUESTION: It ____________ (rain) since last night.A. RainingB. Has been rainingC. Rains D. Rained EXPLANATIONHas been indicates describing actions that will continue up until a point in the future. QUESTION: I have already got a ____________ at a hotel in Murree. We shall have no problems.A. PrescriptionB. PropertyC. Reserve D. Reservation EXPLANATIONReservations are an arrangement to have something (as seating in a restaurant) held for someones use and are usually made for events or dates at hotels and restaurants. QUESTION: Select words that describe the word: GlaredA. Frown or blazeB. Shine or sparkle C. Grin or extinguishD. Frown or eliminate EXPLANATIONA glare is a a fierce or angry stare. QUESTION: Choose the correct type of tense: We will visit the museum.A. PresentB. PastC. FutureD. None of these options is correct EXPLANATIONWhenever a sentence indicates that you will be doing something, that refers to an action being done in the future. Hence the correct answer is Option C. QUESTION: What are you doing here? I __________________ TV.A. Watching B. Am watching C. Is watching D. Watches EXPLANATION-ing indicates present continuous tense, hence we will go with Option B. QUESTION: Find the error in the following options:A. They talked through the entire movie.B. The plants in this garden does not require much water.C. She always brings turkey sandwiches for lunch.D. None of these options are incorrect EXPLANATIONPlants is a plural noun therefore do must be used. QUESTION: Either my father or my brothers __________ going to sell the car.A. IsB. AreC. WereD. Was EXPLANATIONIf a sentence has two subjects connected by or/nor, either/or, or neither/nor, the verb must agree with the second subject (the subject closer to the verb). In this case, the second subject is brothers which is plural hence we would use are not is. QUESTION: Mariam enjoys eating ___________ cheese.A. AB. AnC. TheD. No article is required in this scenario EXPLANATIONIn general, no article is used with proper nouns, mass nouns where the reference is indefinite, or plural count nouns where the reference is indefinite. QUESTION: The students were awaiting for the arrival of the chief guest.A. The students wereB. Awaiting forC. The arrival ofD. The chief guest. EXPLANATIONNote that await does not take the preposition for. For example, we are awaiting his call. (We will NOT say: We are awaiting for his call.) QUESTION: The sun ___________ (shine) brightly.A. ShineB. ShinedC. ShoneD. Shining EXPLANATIONThe past tense of shine is shone. QUESTION: In all plants, the major sites of photosynthesis are?A. LeavesB. StemsC. RootsD. Branches EXPLANATIONLeaves are the main sites for photosynthesis: the process by which plants synthesize food. Most leaves are usually green, due to the presence of chlorophyll in the leaf cells. It is the light energy absorbed by chlorophyll that drives the synthesis of food molecules in the chloroplast. QUESTION: The set of all genes in any population is termed as?A. Population poolB. Species poolC. Gene poolD. All of these options are correct EXPLANATIONThe gene pool is the set of all genes, or genetic information, in any population, usually of a particular species. This also proves to be the basic level at which evolution occurs. QUESTION: Assymetrical body is a feature of phylum _______________.A. AnnelidaB. ArthropodaC. PoriferaD. Cnidaria EXPLANATIONAsymmetrical animals are those with no pattern or symmetry, such as a sponge. QUESTION: A condition with abnormal amount of fats is called?A. AnorexiaB. BotulismC. PilesD. Obesity EXPLANATIONObesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health. QUESTION: The loss of water from the aerial parts of the plant is known as:A. PhotosynthesisB. TranspirationC. ReproductionD. Respiration EXPLANATIONPhotosynthesis is the process of synthesis of food from inorganic compounds like carbon dioxide and water and sunlight. Transpiration is the process of the release of water vapor from aerial parts, such as leaves, stems, and flowers. Reproduction is the process of producing an offspring for continuation of species. Respiration is the process of releasing energy by breaking down organic compounds like sugars. So, the correct answer is Transpiration. QUESTION: The uterus of the female reproductive system opens into the:A. PlacentaB. Birth canal C. CervixD. All of these options are correct EXPLANATIONThe body of the uterus is connected to the ovaries via the fallopian tubes, and opens into the vagina (birth canal) via the cervix. QUESTION: The thalamus and the hypothalamus are located in which region of the brain?A. Brain stemB. CerebrumC. Cerebellum D. Diencephalon EXPLANATIONThe thalamus is a paired gray matter structure of the diencephalon located near the center of the brain. It is above the midbrain, also called the mesencephalon, allowing for nerve fiber connections to the cerebral cortex in all directions β each thalamus connects to the other via the interthalamic adhesion. QUESTION: Which of the following structures provides greater pathogenicity to the bacteria? A. SlimeB. Cell wallC. Cell membraneD. Capsule EXPLANATIONThe function of the slime layer is to protect the bacterial cells from environmental dangers such as antibiotics and desiccation. The slime layer allows bacteria to adhere to smooth surfaces such as prosthetic implants and catheters, as well as other smooth surfaces like petri-dishes. QUESTION: This is a reduced compound:A. CO2B. O2C. NADHD. NAD+ EXPLANATIONNAD+ is the oxidized form of the molecule; NADH is the reduced form of the molecule after it has accepted two electrons and a proton (which together are the equivalent of a hydrogen atom with an extra electron). When electrons are added to a compound, they are reduced. QUESTION: Synaptic vesicles discharge which hormone at the neuromuscular junction?A. AcetylcholineB. AdrenalineC. EstradiolD. Testosterone EXPLANATIONAdrenaline is a hormone released from the adrenal glands. Estradiol is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of the estrous and menstrual female reproductive cycles. Testosterone is the primary sex hormone and an anabolic steroid (a synthetic steroid hormone that resembles testosterone in promoting the growth of muscle) in males. QUESTION: Photosystems are located in the ___________.A. StromaB. Chloroplast envelopeC. Thylakoid membranesD. The intergrana EXPLANATIONStroma contains most of the enzymes required to produce carbohydrate molecules. The chloroplast envelope encloses a dense fluid filled region stroma. QUESTION: In enzymatic mechanism, the substrate bind to the enzyme active site to produce?A. ReactantsB. EnzymesC. ProductsD. All of these EXPLANATIONAn enzyme attracts substrates to its active site, catalyzes the chemical reaction through which products are formed, and then allows the products to dissociate (separate from the enzyme surface). The combination formed by an enzyme and its substrates is called the enzymeβsubstrate complex. QUESTION: The frequency of an allele if it is evolutionary successful is?A. IncreasedB. DecreasedC. No changeD. None of these options is correct EXPLANATIONAllele frequency, or gene frequency, is the relative frequency of an allele (a variant of a gene) at a particular locus in a population, expressed as a fraction or percentage. Natural selection, genetic drift, and gene flow are the mechanisms that cause changes in allele frequencies over time. This variation is heritable (i.e., there is a genetic basis to the variation, such that offspring tend to resemble their parents in this trait). QUESTION: The protein coat of a virus enclosing nucleic acid is called the?A. VectorB. Capsid C. Plasmid D. Genome EXPLANATIONCapsid gives a definite shape to viruses. It is made up of protein subunits called capsomeres. QUESTION: Urethra and vagina have __________ openings to the exterior.A. CommonB. IndependentC. Both A and B options are correctD. None of these options are correct EXPLANATIONUrethra is the tube that allows the urine to pass through it whereas the vagina is the birth canal. Normally the two are not connected, although in rare cases, a birth defect causes the urethra and vagina to become one. This is known as the urogenital sinus. QUESTION: Which of the following changes length during sarcomere contraction? A. Thick filamentsB. Thin filamentsC. H zoneD. All of these options are correct EXPLANATIONThe H zoneβthe central region of the A zoneβcontains only thick filaments and is shortened during contraction. Remember that the actin and myosin filaments themselves do not change length, but instead slide past each other. QUESTION: A structural component that is found in all viruses is?A. EnvelopeB. DNAC. CapsidD. Tail Fibers EXPLANATIONCapsid is the protein coat that gives a definite shape to viruses. QUESTION: Which of these is not a reflex action?A. Secretion of sweatB. SalivationC. Flexion due to needle prickD. Blinking of eyes due to strong light EXPLANATIONAn automatic (involuntary) neuromuscular action excited by a defined stimulus is called reflex action. Sweating is not a reflex action. It is primarily a means of temperature regulation. QUESTION: Smooth endoplasmic reticulum is abundant in which types of cells?A. Lipid metabolismB. Protein metabolismC. Glucose metabolismD. Calcium metabolism EXPLANATIONThe smooth endoplamsic reticulum helps in the metabolism of many different types of molecules, especially lipids. Therefore, it is abundant in lipid-metabolising cells. QUESTION: Cytochromes are electron transport intermediates containing?A. MyoglobinB. HaemC. GlobulinD. Fibrin EXPLANATIONCytochromes are proteins that contain haem as their prosthetic group and whose principal biological function, in the cells of animals, plants, and microorganisms, is electron transport. QUESTION: When was the Tobacco mosaic virus successfully crystalized?A. 1935B. 1930C. 1932D. 1920 EXPLANATIONTwo scientists contributed to the discovery of the first virus, the Tobacco mosaic virus. Ivanoski reported in 1892 that extracts from infected leaves were still infectious after filtration through a Chamberland filter candle. Bacteria are retained by such filters. The filterable agents were purified in 1935 when Stanley was successful in crystalizing the TMV. QUESTION: Which of the following results from conjugation in paramecium?A. Cell deathB. Cell divisionC. BuddingD. Recombination EXPLANATIONConjugation is a method of sexual reproduction in paramecium. In this, two paramecia of opposite mating types come in contact with each other. They attach to their ventral surfaces and the exchange of genetic material takes place through the cytoplasmic bridge. The male pronucleus fuses with the female pronucleus to form the diploid zygote which undergoes a series of divisions to form the mature organism. Thus, the correct answer is option B. QUESTION: During inspiration, the diaphragm:A. ContractsB. RelaxesC. Contracts and relaxesD. None of these options is correct EXPLANATIONThe process of breathing, or respiration, is divided into two distinct phases. The first phase is called inspiration or inhaling. When the lungs inhale, the diaphragm contracts and pull downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs. QUESTION: Glycophorin is involved in which of the following diseases?A. Viral feverB. Common coldC. AsthmaD. Malaria EXPLANATIONGlycophorins are heavily glycosylated sialoglycoproteins of human and animal erythrocytes. In humans, there are four glycophorins: A, B, C, and D. Glycophorins play an important role in the invasion of red blood cells (RBCs) by malaria parasites, which involves several ligands binding to RBC receptors. QUESTION: Which of the following is an example of a marine annelid?A. NeriesB. StylariaC. EarthwormD. Leech EXPLANATIONThe most common marine worms belong to the phylum Annelida. They are distinguished by the little rings or segments that make up their bodies. The most common marine annelids are polychaetes. Neries belongs to the class polychaetes. QUESTION: Two pea plants are crossed. One plant is homozygous dominant for purple flowers, and the other is homozygous recessive for white flowers. What fraction of the F2 population will have white flowers?A. 1/4B. 1/2C. 1/8D. 1/16 EXPLANATIONThe F1 generation will consist of heterozygous purple flowers. When these heterozygous flowers are crossed with each other, the resulting F2 generation will consist of purple and white flowers in a ratio of 3:1. QUESTION: In the process of esterification, -OH is derived from?A. EtherB. AlcoholC. WaterD. Both Options A and B are correct EXPLANATIONThe question directly lifts from a statement in the Punjab book. According to the book, the carboxylic acid releases H, which combines with a hydroxyl (-OH) group released from alcohol to form a water molecule. The remaining carboxylic acid and alcohol join together by an ester linkage to form an ester. However, that is incorrect. Actually, the OH group is released by carboxylic acid and H by alcohol. But since the options do not even list carboxylic acid, alcohol is our only choice. QUESTION: The enzyme which plays an important role in HIV pathogenesis:A. RNA polymerase IB. DNA polymerase IIC. Reverse Transcriptase ID. Reverse Transcriptase EXPLANATIONHIV pathogenesis is thought of as a chronic infection involving slow degradation of immunity that ultimately leads to AIDS. When HIV RNA enters the cell it must be `reverse transcribed` into proviral DNA before it can be integrated into the DNA of the host cell. HIV uses its reverse transcriptase enzyme to convert RNA into proviral DNA inside the cell. QUESTION: A monohybrid cross yielded a 3:1 ratio in F2. What could be the mode of inheritance?A. SegregationB. Independent assortmentC. Both Options A and B are correctD. None of these options is correct EXPLANATIONThe law of segregation states that every individual possesses two alleles and only one allele is passed on to the offspring. In a monohybrid cross, both the alleles are expressed in the F2 generation without any blending. Thus, the law of segregation is based on the fact that each gamete contains only one allele. QUESTION: This group of animals has three bones in the ear:A. ReptilesB. MammalsC. Both reptiles and mammalsD. Birds and mammals EXPLANATIONModern mammals are unique among vertebrates for possessing three tiny bones in the middle ear. The malleus, incus, and stapes (commonly known as the hammer, anvil, and stirrup) work as part of a chain that transmits sound towards the skull. Birds and reptiles have only one bone to perform this function. QUESTION: What happens during muscle contraction to the length of each myosin and actin filament?A. The A-band becomes shortB. The I-band elongatesC. There is no change in the sarcomere lengthD. The Z-lines get closer EXPLANATIONWhen a sarcomere contracts, the Z lines move closer together and the I band gets smaller. The A band stays the same width and, at full contraction, the thin filaments overlap. QUESTION: Lymphocytes are found in the:A. Lymph capillaryB. Lymph vesselC. Lymph trunkD. Lymph node EXPLANATIONLymphocytes are a type of white blood cell. They play an important role in our immune system, helping our body fight off infection. Most lymphocytes reside within lymphoid organs (lymph nodes, thymus, spleen, and bone marrow). Only about 2% to 5% of lymphocytes circulate in blood. QUESTION: The presence of peptidoglycan in gram-positive bacteria is:A. 40% of dry weightB. 50% of dry weightC. 10% of dry weightD. 80% of dry weight EXPLANATIONGram-positive bacteria have a thick peptidoglycan layer, which comprises 50% of the dry weight in some bacterial cells. (Punjab book) QUESTION: If the non-protien part is loosely attached to the protein part in the enzyme, it is known as ______.A. CoenzymeB. Prosthetic groupC. CofactorD. Apoenzyme EXPLANATIONProsthetic groups are compounds bound to enzymes by a covalent bond and their change from one form to another and back takes place in a single catalytic cycle. Coenzymes are organic molecules and quite often bind loosely to the active site of an enzyme. The term cofactors unite coenzymes and prosthetic groups. The meaning of apoenzyme is a protein that forms an active enzyme system by combination with a coenzyme. QUESTION: Enzymes for light-dependent reactions of photosynthesis would most likely be associated with:A. Outer membrane of the chloroplastB. Inner membrane of the chloroplastC. Stroma of the chloroplastD. Thylakoid membranes of the chloroplast EXPLANATIONEnzymes for the light-dependent reactions are associated with the thylakoid membranes of the chloroplasts. QUESTION: The electron transport chain in plants consists of an electron carrier called?A. PqB. PcC. PtD. Po EXPLANATIONFact. QUESTION: Muscle contraction depends on:A. Nerve impulseB. EnergyC. CalciumD. All of these options are correct EXPLANATIONMuscle contraction begins when the nervous system generates a signal. The signal, an impulse called an action potential, travels through a type of nerve cell called a motor neuron. The source of energy that is used to power the movement of contraction in working muscles is adenosine triphosphate (ATP). Ca2+ ions play an important role in muscle contraction by creating interactions between the proteins, myosin, and actin. The Ca2+ ions bind to the C component of the actin filament, which exposes the binding site for the myosin head to bind to in order to stimulate a muscle contraction. QUESTION: The cell organelles involved, in some cases, with extra-cellular digestion are _____________.A. Golgi complexB. LysosomesC. PeroxisomesD. Glyoxysomes EXPLANATIONLysosomes function as the digestive system of the cell, serving both to degrade material taken up from outside the cell and to digest obsolete components of the cell itself. A Golgi body, also known as a Golgi apparatus, is a cell organelle that helps process and package proteins and lipid molecules, especially proteins destined to be exported from the cell. Peroxisomes are organelles that sequester diverse oxidative reactions and play important roles in metabolism, reactive oxygen species detoxification, and signaling. The glyoxysome is a plant peroxisome, especially found in germinating seeds, involved in the breakdown and conversion of fatty acids to acetyl-CoA for the glyoxylate bypass. QUESTION: Which of the following genetic diseases is caused by mutations in a membrane protein?A. Alzheimers diseaseB. Parkinsons diseaseC. AnemiaD. Hemolytic anemia EXPLANATIONMutations probably include a combination of age-related changes in the brain, along with genetic, environmental, and lifestyle factors. Parkinsons disease is caused by a loss of nerve cells in the part of the brain called the substantia nigra. Dietary deficiency β lack of iron, vitamin B12, or folic acid in the diet causes anemia. QUESTION: Which of the following is true of both bacterial conjugation and meiosis?A. Both processes produce four haploid cellsB. Both processes are a form of asexual reproductionC. Both processes involve genetic recombinationD. None of these options is correct EXPLANATIONBacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells. Meiosis creates new combinations of genetic material in each of the four daughter cells. These new combinations result from the exchange of DNA between paired chromosomes. Such exchange means that the gametes produced through meiosis exhibit an amazing range of genetic variations. QUESTION: The period during which a girl sexually matures is called:A. Menstrual cycleB. PubertyC. ChildhoodD. Teens EXPLANATIONPuberty is when a childs body begins to develop and change as they become an adult. QUESTION: Antibodies play an important role against microorganisms and other pathogens. To which type of proteins do they belong?A. GlobularB. FunctionalC. FibrousD. Both Options A and B are correct EXPLANATIONAntibodies belong to a group of globular proteins of serum/plasma; they are therefore also known as immunoglobulins. Antibodies react specifically with antigens, which are responsible for the production or induction of those specific antibodies. QUESTION: The animals in which there are separate male and female individuals are called?A. UnisexualB. BisexualC. AsexualD. Hermaphrodite EXPLANATIONAnimals that have either male or female reproductive organs are known as unisexual organisms. These organisms exhibit the property of sexual dimorphism. Sexual dimorphism are the differences in appearance between males and females of the same species. Lizards are reptiles that are bisexual. There are no different sexes but both the sexes are present in the same organism. Humans are unisexual. Thus, the correct answer is option A. QUESTION: To produce ATP (adenosine triphosphate) in muscles, creatine phosphate (CP) transfers __________ to adenosine diphosphate (ADP).A. OxygenB. AdenosineC. CytosineD. Phosphate EXPLANATIONOne of the ways that ATP supply is regenerated in a muscle fiber is through the molecule creatine phosphate (or phosphocreatine). In the process of regeneration of ATP, creatine phosphate transfers a high-energy phosphate to ADP. The products of this reaction are ATP and creatine.Β QUESTION: Which was the first virus to be successfully crystalized?A. TMVB. SmallpoxC. PoliovirusD. Adenovirus EXPLANATIONTwo scientists contributed to the discovery of the first virus, the Tobacco mosaic virus. Ivanoski reported in 1892 that extracts from infected leaves were still infectious after filtration through a Chamberland filter candle. Bacteria are retained by such filters. The filterable agents were purified in 1935 when Stanley was successful in crystalizing the TMV. QUESTION: The path of electrons through the two photosystems is called?A. S schemeB. X schemeC. Z schemeD. Y scheme EXPLANATIONFact. QUESTION: The T-lymphocytes and B-lymphocytes are the major cells of the:A. ThymusB. Lymph nodesC. Adrenal glandsD. Lymphatic vessels EXPLANATIONLymph nodes contain lymphocytes, a type of white blood cell, and are primarily made up of B cells and T cells. B cells are mainly found in the outer cortex where they are clustered together as follicular B cells in lymphoid follicles, and T cells and dendritic cells are mainly found in the paracortex. QUESTION: In which class of phylum Mollusca, is the octopus included?A. GastropodaB. CephalopodaC. PelecypodaD. Scaphopoda EXPLANATIONOctopus is an organism that belongs to the group of molluscs. They belong to the class cephalopod. The organisms have a bilateral form of symmetry. It has two eyes and four pairs of arms and, like other cephalopods, it is bilaterally symmetric. There are pads on the arms. This helps to move under the water. Thus, the correct answer is option B. QUESTION: In reproduction, semen refers to which of the following?A. Fluid and spermsB. Blood and waterC. Blood and spermsD. Blood and fluid EXPLANATIONSemen, also called seminal fluid, is emitted from the male reproductive tract and contains sperm cells, which are capable of fertilizing the females eggs. Semen also contains liquids that combine to form seminal plasma, which helps keep the sperm cells viable. QUESTION: How does each photoexcited electron pass from PS2 to PS1?A. ETCB. ChemiosmosisC. PhotolysisD. Photosynthesis EXPLANATIONThe electron transport chain is a series of four protein complexes that couple redox reactions, creating an electrochemical gradient that leads to the creation of ATP in a complete system named oxidative phosphorylation. It occurs in mitochondria in both cellular respiration and photosynthesis. Electrons undergo an electron transport chain from PS2 to PS1. QUESTION: Which of the following is the respiratory surface in human beings?A. LungsB. AlveoliC. WindpipeD. Alveolar duct EXPLANATIONThe surface which participates in the exchange of O2 and CO2 is called the respiratory surface. The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out. Oxygen breathed in from the air passes through the alveoli and into the blood and travels to the tissues throughout the body. QUESTION: The patellar reflex and the Achilles reflex are examples of?A. Monosynaptic reflexB. Polysynaptic reflexC. Hemisynaptic reflexD. Both Options A and B are correct EXPLANATIONThe knee-jerk reflex, also called the patellar reflex, is the sudden kicking movement of the lower leg in response to a sharp tap on the patellar tendon, which lies just below the kneecap. In reaction, these muscles contract, and the contraction tends to straighten the leg in a kicking motion. The Achilles reflex is a monosynaptic stretch reflex similar to the patellar reflex. In the Achilles reflex, the hammer taps the Achilles tendon while the foot is dorsiflexed, and the foot, in response, should jerk toward the plantar surface. The Achilles reflex originates in the S1 and S2 nerve roots. QUESTION: __________ are among the smallest known virus.A. PicornavirusB. ParvovirusesC. Herpes virusD. Rota virus EXPLANATIONFact. QUESTION: Structures that were once functional in the past but no longer serve a purpose due to evolutionary adaptations and physiological changes are referred to as?A. Vestigial structuresB. Analogous structuresC. Homologous structuresD. None of these options is correct EXPLANATIONThe term, vestigial, is used in science to describe structures like animal organs, tissues, or bones that may have been used by an ancestor but arent anymore. For example, snakes have vestigial structures where limbs would have been when they walked on four legs. QUESTION: The complete breakdown of glucose molecule takes place in which of the following?A. Alcoholic fermentationB. Lactic acid fermentationC. Aerobic respirationD. None of these options is correct EXPLANATIONThe breakdown of glucose takes place in the mitochondria inside the cell in the presence of oxygen to release energy (aerobic respiration). Alcoholic fermentation begins with the breakdown of sugars by yeasts to form pyruvate molecules, which is also known as glycolysis. Lactic acid fermentation is a metabolic process by which glucose or other six-carbon sugars (also, disaccharides of six-carbon sugars, e.g. sucrose or lactose) are converted into cellular energy and the metabolite lactate. QUESTION: Which of the following movements are possible in a pivot joint?A. Flexion and extensionB. Adduction and abductionC. RotationD. Extension flexion and rotation EXPLANATIONA pivot joint allows rotation around an axis, e.g. between the first and second neck vertebrae. It is the movement of the pivot joint that allows one to move their head back and forth. QUESTION: Which of the following is paired correctly?A. Pisces - jellyfishB. Echinodermata - cuttlefishC. Mollusca - starfishD. Arthropoda - silver fish EXPLANATIONThe scientific name of the silver fish is Lepisma saccharina. They belong to the phylum Arthropoda and class Insecta. QUESTION: Which of the following is the most widely accepted theory for the ascent of sap?A. Water potentialB. Cohesion tensionC. Root pressureD. Imbibition EXPLANATIONThere are many theories explaining the ascent of sap, including: 1. Cohesion-Tension Theory: The theory states thatΒ transpiration pull or tension, cohesion property of water, and hydration of the cell walls (i.e., adhesion) are collectively responsible for the ascent of sap.Β 2. Root pressure theory: The theory states that the phenomenon of root pressure is responsible for the ascent of sap.Β 3. Imbibition: According to this theory, water rises by imbibition through the thick walls of the xylem cells, as well as those of the sclerenchyma of the phloem. The forces of imbibition range from 100 to 1000 atm and this would seem adequate for carrying water to any required distance. Out of all these, the cohesion-tension theory is most widely accepted. QUESTION: Which of the following is not an evidence of evolution?A. Fossil recordB. Common ancestor organismsC. Vestigial structuresD. None of these options is correct EXPLANATIONFossils provide solid evidence that organisms from the past are not the same as those found today; fossils show a progression of evolution. Fossils, along with the comparative anatomy of present-day organisms, constitute the morphological, or anatomical, record. By comparing the anatomies of both modern and extinct species, paleontologists can infer the lineages of those species. Structures that have lost their use through evolution are called vestigial structures. They provide evidence of evolution because they suggest that an organism changed from using the structure to not using the structure, or using it for a different purpose from a common ancestor. QUESTION: The part of the spinal cord where interneurons are present is called:A. White matterB. Gray matterC. Lumbar enlargementD. Cervical enlargement EXPLANATIONGray matter in the spinal cord is neural tissue that is dominated by the cell bodies of neurons, neuroglia, and unmyelinated axons, and it surrounds the narrow central canal. It is neural tissue that contains large numbers of myelinated and unmyelinated axons. QUESTION: These are the properties of lipids:A. Insoluble in water and soluble in fatB. High energy contentC. Structural component of cell membraneD. All of these options are correct EXPLANATIONFact. QUESTION: The animals that have features of both mammals and reptiles are?A. Duckbill platypusB. Spiny anteaterC. WolvesD. Both Options A and B are correct EXPLANATIONPlatypus, also called the duck-billed platypus, is a mammal, and echnida, also called the spiny anteater, is also an egg-laying mammal. They both have characteristics of reptiles & mammals which are as follows: Warm-blooded Possess sweat-producing gland Possess milk-producing gland Lay eggs QUESTION: What event occurs in the menstrual cycle when the level of progesterone declines?A. OvulationB. MenstruationC. MenopauseD. Fertilization EXPLANATIONWhen the follicular phase begins, levels of estrogen and progesterone are low. As a result, the top layers of the thickened lining of the uterus (endometrium) break down and are shed, and menstrual bleeding occurs. QUESTION: Which of the following conditions is not required to be true for a population in the Hardy-Weinberg equilibrium?A. Random mutationsB. Large populationC. No natural selectionD. Random mating EXPLANATIONIn order for equilibrium to occur, there must be a large, randomly mating population with no selection, genetic drift, migration, or mutation.Β A small populationΒ cannot be in the Hardy-Weinberg equilibrium. Random mutations should not be present thus the correct answer is A. QUESTION: Which of the following statements about the systemic effect of bacterial cells is true?A. Gram-negative bacteria are more likely to cause systemic effects because they lack an outer membrane which means they can more quickly to infect host cellsB. Gram-negative bacteria are more likely to cause systemic effects because their outer membrane protects them from antibioticsC. Both Options A and B are correctD. None of these options is correct EXPLANATIONSystemic effect is an adverse effect of an exposure that affects the body as a whole, rather than one part. Gram-negative bacteria have an outer capsule that provides resistance against antibiotics and makes the bacterium more pathogenic. Gram-positive bacteria lack this outer capsule. Therefore, gram-negative bacteria are more likely to cause infections (systemic effects). QUESTION: Which one of the following is a non-protein group covalently bonded to a few respiratory enzymes among others?A. Nicotine adenine dinucleotideB. Flavin adenine dinucleotideC. Nicotinamide adenine dinucleotide phosphateD. All of the above options are correct EXPLANATIONIn biochemistry, flavin adenine dinucleotide is a redox-active coenzyme associated with various proteins, which is involved with several enzymatic reactions in metabolism. QUESTION: What is the property of the part of a cell membrane which is in contact with the external and internal environment?A. HydrophobicB. HydrophilicC. NeutralD. Both Options A and B are correct EXPLANATIONThe plasma membrane consists of a lipid bilayer associated with proteins. The polar phospholipid heads are hydrophilic and are directed outwards, while the non-polar tails are hydrophobic and are directed inwards, facing each other. Therefore, the hydrophilic ends are in contact with both the external extracellular environment and the internal environment of the cell. QUESTION: The spinal cord consist of which type of cell bodies?A. Sensory neuronB. Motor neuronC. Connector neuronD. All of these options are correct EXPLANATIONFact. QUESTION: Standard electrode potential is denoted by:A. EB. E1C. E0D. a EXPLANATIONUnder standard conditions (temperature = 298K, pressure = 1 atm, concentration = 1 mol per dm3), the standard electrode potential occurs in an electrochemical cell. The symbol βE0 cellβ represents the standard electrode potential of a cell. QUESTION: What is the coordination number of Pt in [PtCl(NO2)(NH3)4]?A. 2B. 4C. 6D. 7 EXPLANATIONThere are 6 ligands around the Pt metal. 1 Cl Atom, 1 NO2, and 4 NH3. Hence, the coordination number is 6. QUESTION: Limiting reactant controls the amount of ________.A. Reactant B. ProductsC. Both Options A and B are correctD. None of these options is correct EXPLANATIONThe limiting reactant is the one which gets consumed first in a chemical reaction. Hence, the concentration of product formed depends on it. QUESTION: Which of the following element is not usually present in all proteins?A. CarbonB. HydrogenC. NitrogenD. Sulphur EXPLANATIONProteins are made from amino acids and out of the 20 available amino acids, only 2 contain sulphur. QUESTION: The biochemical process used in the synthesis of alcohol in the presence of yeast is called as ___________.A. RespirationB. PhotosynthesisC. FermentationD. Aerobic respiration EXPLANATIONFermentation is the process whereby molecules such as glucose are broken down anaerobically producing alcohol. QUESTION: First member of alkynes is called ___________.A. EthyleneB. AcetyleneC. AcetoneD. Ethene EXPLANATIONThe first member is called Ethyne or Acetylene. QUESTION: BH3 has H-B-H bond angles of 120Λ with geometry as:A. LinearB. Trigonal planarC. TetrahedronD. Bent EXPLANATIONBH3 has a trigonal planar shape with 120Β° bond angles and has 3 bonded electron pairs and no lone electron pairs. QUESTION: Cyclic compounds consist of all of the following except?A. AlicyclicB. AromaticC. Acyclic compoundsD. Carbocyclic compounds EXPLANATIONHere are the definitions of each of the above terms: Alicyclic: contains one or more all-carbon rings which may be either saturated or unsaturated, but do not have aromatic character Aromatic: organic compounds also known as mono- and polycyclic aromatic hydrocarbons. The parent member is benzene (cyclic in nature). Acyclic: an open-chain compound or acyclic compound is a compound with a linear structure, rather than a cyclic one. Carbocyclic: A cyclic organic compound containing all carbon atoms in ring formation is designated as a carbocyclic compound, QUESTION: Metals look shiny as light falling on metal surface collide with mobile electrons and make them ______. These electrons then give out light when they are _________.A. Neutral, excitedB. Excited, de-excitedC. De-excited, excitedD. None of these options is correct EXPLANATIONWhen a light photon arrives at the metal surface, it is absorbed. This process promotes the electrons to a higher energy level. However, when the electrons come back to lower energy, the photon of light is re-emitted. Hence, the metal appears shiny. QUESTION: Why is phenol more acidic than Alcohol?A. Due to the presence of resonance in phenolB. Due to the absence of resonance in alcoholC. Both Options A and B are correctD. Because in phenol, hydrogen is attach to oxygen EXPLANATIONThe acidity of any compound generally depends on its tendency to release hydrogen ions. So in the case of ethanol, it is very tough to remove hydrogen ions from it so we can say that ethanol is less acidic than phenol, while on the other side, phenol is more acidic than ethanol because it can lose the hydrogen ion very easily because delocalization of electrons takes place in phenols by resonance. QUESTION: If pressure and volume of a gas are variable while the temperature remains constant, this belongs to:A. Charless lawB. Boyles lawC. Avogadros lawD. Pascals law EXPLANATIONThis question has been repeated in multiple other papers, hence indicating that this is a high-yield concept. Boyleβs law states that the pressure (p) of a given quantity of gas varies inversely with its volume (v) at constant temperature; i.e., in equation form, pv = k, a constant. QUESTION: SN1 reactions are favored by which of the following reactions?A. WaterB. BenzeneC. Carbon TetrachlorideD. Carbon disulphide EXPLANATIONSN1 reactions are favoured by Polar Protic Solvents. These are polar solvents which are able to show hydrogen bonding. QUESTION: During the course of a SN1 reaction, the intermediate species formed is:A. A carbocationB. A free radicalC. A carbanionD. An intermediate complex EXPLANATIONWhen nucleophilic substitution takes place, the bond between C and X dissociates. Now there are only 3 bonds on carbon and carbon bears a positive charge. This is called a carbocation. Hence, the correct option is A. QUESTION: Instantaneous rate of reaction is the rate at any?A. At equilibriumB. One instantC. Given temperatureD. Given pressure EXPLANATIONThe rate of reaction at a particular point or instant is called instantaneous rate. QUESTION: Redox reactions actually transfer:A. ElectronsB. ChargesC. EnergyD. Hydrogen ions EXPLANATIONRedox reactions are those in which oxidation & reduction both take place. They are defined by gain or loss in electrons, i.e. reduction is gain in electrons and vice versa. QUESTION: Which of the following acid solutions is used for the seasoning of food?A. Butyric acidB. Phthalic acidC. Lactic acidD. Acetic acid EXPLANATIONAcetic acid lowers the pH of food giving it an acidic taste, for example salt and vinegar chips. QUESTION: Cholesteryl Benzoate turns milky at?A. 123Β°CB. 135Β°CC. 145Β°CD. 179Β°C EXPLANATIONWhen heated, the Cholesteryl Benzoate melts at 145Β°C to form a milky liquid, and at 179Β°C the milky liquid suddenly becomes clear. QUESTION: In the production of wrought iron Mg, Si, and P are removed in the form of:A. OxidesB. SilicatesC. SlagD. Carbonates EXPLANATIONSlag is the name given to stony waste matter separated from metals during the smelting or refining of ore. QUESTION: Which one of the following structures does the benzene molecule have?A. Two double bondsB. Delocalized pi-electron chargeC. Three double bondsD. One sigma bond EXPLANATIONBenzene is a cyclic molecule in which all of the ring atoms are sp2-hybridized that allows the Ο electrons to be delocalized in molecular orbitals that extend all the way around the ring, above and below the plane of the ring. QUESTION: Carboxylic acids form dimers due to _________.A. Small sizesB. Polarity of C-O bondC. H-bondingD. Dipole-Dipole interactions EXPLANATIONCarboxylic acids exist as dimers due to intermolecular hydrogen bonding which is not broken completely even in the vapour phase. QUESTION: Activator of phosphatase enzyme is _________.A. Mn2+B. Mg2+C. Zn2+D. None of these options is correct EXPLANATIONMagnesium ions act as cofactors necessary for enzyme activity. QUESTION: A liquid crystalline state exists between two temperatures (melting temperature and ______ temperature).A. BoilingB. FreezingC. ClearingD. All of these options are correct EXPLANATIONA liquid crystalline state exists between two temperatures i.e. melting temperature and clearing temperature. (PTB I, p. 94) QUESTION: Plasma the fourth state of matter was identified by?A. BerzeliusB. William CrooksC. DaltonD. Rutherford EXPLANATIONThe existence of the fourth state of matter was first identified by Sir William Crookes in 1879. QUESTION: Acetaldehyde undergoes polymerization with concentrated H2SO4 to form _______.A. AcetylidesB. ParaldehydeC. BakeliteD. Meta Acetaldehyde EXPLANATIONUnder the presence of concentrated H2SO4, Acetaldehyde is polymerised to Paraldehyde. QUESTION: There are just only a few stable compounds, formed by noble gases like:A. XeF2B. XeOF2C. XeO3D. All of these options are correct EXPLANATIONXenon, being a noble gas and having an octet valence electron configuration, is an inert gas. However, it is capable of reacting with elements of high electronegativity, such as Fluorine, Chlorine, and Oxygen; with Fluorine, forming the most stable compounds. QUESTION: Who attributed the deviation of real gases from ideal behavior?A. Boyles lawB. Charless lawC. Avogadros lawD. Van der Waals EXPLANATIONVan Der Waals modified the ideal gas law to describe the behavior of real gases by explicitly including the effects of molecular size and intermolecular forces. QUESTION: An electron in an atom is completely described by its?A. 2 quantum numbersB. Only one quantum numberC. Four quantum numbersD. 3 quantum numbers EXPLANATIONTo completely describe an electron in an atom, four quantum numbers are needed: energy (n), angular momentum (β), magnetic moment (mβ), and spin (ms). QUESTION: Enzymes are __________ in nature.A. ProteinsB. CarbohydratesC. LipidsD. Nucleic acid EXPLANATIONEnzymes are proteins that help speed up metabolism, or the chemical reactions in our bodies. QUESTION: The properties of liquid crystals are intermediate between crystals and:A. Anisotropic liquidsB. Nematic liquidsC. Isotropic liquids D. Liquids EXPLANATIONLiquid crystals are a state of matter intermediate between that of a crystalline solid and an isotropic liquid. They possess many of the mechanical properties of a liquid, e.g. - high fluidity, inability to support shear, formation, and coalescence of droplets. QUESTION: Fractions of crude petroleum can be obtained by using ___________.A. Destructive distillationB. Fractional distillationC. Vacuum distillationD. Distillation EXPLANATIONCrude oil is separated by fractional distillation. Crude oil is heated to vaporize the different hydrocarbons in a tank which is cool at the top and hot at the bottom. The vapors then rise and the different hydrocarbons condense at their specific boiling points, allowing them to be separated. QUESTION: In proteins, the hydrogen-bonding is present between ________.A. C-HB. N-HC. O-HD. Cl-H EXPLANATIONFor this case, both Option B and C would stand correct; however, the intensity of hydrogen bonding in O-H would be less, since it is hindered by the presence of the C=O linked with the O-H. The delocalization of electrons, spreading throughout the -COOH group, makes Hydrogen Bonding relatively less effective than what is seen with N-H. QUESTION: Which of the following centers are present in the carbonyl compounds?A. ElectrophilicB. NucleophilicC. Electron deficientD. All of these options are correct EXPLANATIONThe carbon-oxygen double bond is polarised due to higher electronegativity of oxygen relative to carbon. Hence, the carbonyl carbon is an electrophilic/electron defecient (lewis acid) and carbonyl oxygen is, a nucleophilic (lewis base) centre. QUESTION: Shifting the position of equilibrium can be used to increase:A. TemperatureB. PressureC. Yield of reactionD. All of these options are correct EXPLANATIONChanging the position of equilibrium will cause the yield to increase towards the side which counters the change. For example, if the equilibrium position is changed towards the reactant side, more products will be formed to counter the change. QUESTION: Reduction of alkyl halides in the presence of Zn and mineral acid produces ________.A. AlkenesB. Alkanes C. AlkynesD. Alcohols EXPLANATIONAlkyl halides (except fluorides) on reduction with zinc dilute hydrochloric acid give alkanes. Zn +H2 β ZnH2 ZnH2 + 2CH3Cl β ZnCl2 +2CH4 QUESTION: An aromatic compound that cannot be obtained from coal tar is:A. BenzeneB. TolueneC. PhenolD. Diphenylmethane EXPLANATIONDiphenylmethane is a synthetic compound, manufactured by The Friedel-Craft Reaction of benzyl chloride with benzene, in the presence of aluminum chloride. QUESTION: Polymerization of ethene produces which of the following polymers?A. PolyvinylB. PolethylC. PolyethyleneD. Polyethoxy EXPLANATIONEthene is polymerised to form polyethene which is also called polyethylene. QUESTION: In an exothermic reaction (reversible), which of the following has a positive value?A. EnthalpyB. EntropyC. Gibbs free energyD. None of these options is correct EXPLANATIONExothermic reaction needs more activation energy as it is a non-spontaneous reaction. So, for this reaction, Gibbs free energy becomes positive. Hence, Option C is correct. QUESTION: If the concentration of reactants in a chemical reaction is unity, then the rate is called:A. Unit rate constantB. Specific rate constantC. Relative rate constantD. Average rate constant EXPLANATIONSpecific rate constant at a given temperature may be defined as the rate of reaction when the molar concentration of each reactant is unity. QUESTION: Which reaction will need maximum energy to remove its one electron?A. Na β Na++ e-B. Ca β Ca++ e-C. K β K++ e-D. C2+β C3+ + e- EXPLANATIONIn Option D, an electron is being removed from an already positively charged ion, not a neutral atom like the others. The nuclear attraction experienced by the outer electrons would be stronger due to the positive charge thus more energy would be required to remove an electron. QUESTION: The reaction of vinyl acetylene with HCl produces?A. Polyvinyl polymerB. Polyvinyl AcetyleneC. NeopreneD. Chloroprene EXPLANATIONCH2=CH-Cβ‘CH + HCl β CH2=CH-C(Cl)=CH2 QUESTION: Carboxylic acids are formed by the hydrolysis of ________.A. Ester & NitrilesB. Nitriles & AminesC. Alkenes & AlkynesD. Esters & Alcohols EXPLANATIONEster hydrolysis is a reaction that breaks an ester bond with a molecule of water or a hydroxide ion to form a carboxylic acid and an alcohol. Nitriles can be hydrolyzed to carboxylic acids in acidic aqueous solutions. QUESTION: Which of the species has a permanent dipole moment?A. SF4 B. SiF4C. BF3D. XeF4 EXPLANATIONSince sulfur has 6 valence electrons, two of them get bonded (4 electrons) while other 2 electrons remain as a lone pair. Due to the presence of lone pairs and F ligands, it becomes a permanent dipole moment. QUESTION: The number of charges present on a cation depends on the number of electrons __________ by the atom.A. GainB. LostC. AcceptD. Produced EXPLANATIONA cation is positively charged and hence, it loses electrons. QUESTION: In aldol condensation, the nucleophile is ________.A. Hydroxyl ionB. CarbocationC. CarbanionD. Water EXPLANATIONThe reaction mechanism below shows that the carbanion is the nucelophile of the reaction: QUESTION: The oxidation number of Nickel in [Ni(CO)4] is:A. 2B. 8C. 6D. 4 EXPLANATION Let x be the oxidation number of Ni in Ni(CO)4. Since the overall charge on the complex is 0, the sum of oxidation states of all elements in it should be equal to 0. Therefore, x+4(0)=0; 0, because CO has no oxidation charge. Hence, x=0. Thus, the oxidation number of Ni in Ni(CO)4 is 0. QUESTION: Which of the following is not a mixture of hydrocarbons?A. Candle waxB. Kerosine oilC. Paraffin oilD. Vegetable ghee EXPLANATIONVegetable ghee may also contain fatty acids and triglycerides which are not hydrocarbons since they contain oxygen as well. QUESTION: Which type of carboxylic acid is produced from the hydrolysis of nitriles?A. Beta-hydroxy carboxylic acidsB. Acids, having one carbon more than the starting materialC. Acids having one carbon less than the starting materialD. Alpha-hydroxy acids EXPLANATIONDuring the conversion of nitriles (compounds, having a cyanide group, Cβ‘N), the cyanide group loses the Nitrogen, and -OOH is added, as a substitute. There is no addition of carbon; however, what happens is, while naming the nitrile, we do not count the carbon of the cyanide group, as part of the alkyl chain. This isnt the case with carboxylic acid, where all the carbons, including that of the acidic group, are included. QUESTION: Dipole forces has a direct relation with the ________.A. Chemical properties of a substanceB. Kinetic properties of a substanceC. Thermodynamic properties of a substanceD. Nature of a substance EXPLANATIONDipole-Dipole interactions result when two dipolar molecules interact with each other through space. This type of interaction between molecules accounts for many physically and biologically significant phenomena such as the elevated boiling point of water (thermodynamic property). QUESTION: The critical temperature of ammonia is _____oC.A. 31.14B. 13.24C. 132.44D. 1.11 EXPLANATIONCritical temperature is the highest temperature at which it is possible to separate substances into two fluid phases. This is 132ΛC for ammonia. QUESTION: The alcohols which are resistant to oxidation reactions are:A. Primary alcoholsB. Secondary alcoholC. Tertiary alcoholD. All of above options are correct EXPLANATIONTertiary alcohols because the carbon atom that carries the OH group does not have a hydrogen atom attached but is instead bonded to other carbon atoms, so 2 hydrogen atoms cannot be lost which is necessary for oxidation. QUESTION: A compound has an empirical (simple) formula, C2H2O. If the experimental molecular weight is found to be in the range of 160-170, the molecular formula of this compound is: (Atomic weight: C = 12.1, H = 1, O = 16) A. C3H6O3 B. C4H4O2C. C8H8O4D. C6H6O3 EXPLANATION The molecularmass of the given empirical formula = 2(12.1) + 1 (1) + 16= 42.2 Let wholenumber ratio of molecular formula = n 160< n x42.2 < 170 160/42.2< n < 170/42.2 3.79 < n< 4.02 Wholenumber n =4 Molecular formula=C2x4H2x4O4 = C8H8O4 QUESTION: The quantum number values for 2p orbitals are:A. n = 2, l = 1B. n = 1, l = 2C. n = 1, l = 0D. n = 2, l = 2 EXPLANATIONn would be 2, as it is in the second shell. l would be 1 as it is for p subshells. QUESTION: Fluorine has the highest electronegativity value which is:A. 3.4B. 4.0C. 1.2D. 2.6 EXPLANATIONOf the main group elements, fluorine has the highest electronegativity (EN = 4.0) and cesium has the lowest electronegativity (EN = 0.79). This indicates that fluorine has a high tendency to gain electrons from other elements with lower electronegativities. We can use these values to predict what happens when certain elements combine. QUESTION: S-S bond is present in which of the ion pairsA. Option A EXPLANATIONS-S bond is present in the pair given in Option D. QUESTION: Which of the following statements is incorrect about amorphous solids?A. They are anisotropicB. They are rigid and incompressibleC. They melt over a wide range of temperatureD. There is no orderly arrangement of particles EXPLANATIONIn amorphous solids, the arrangement of particles is irregular in all directions hence the value of any physical property is the same along any direction. Hence, they are isotropic in nature. Therefore, Option A is the answer. QUESTION: Enzymes speed up the reaction upto:A. 1010B. 2010C. 1030 D. 1510 EXPLANATIONA reaction might be sped up by an enzyme upto 1030 times the original rate. QUESTION: The oscillating object overshoots the rest position due to:A. Restoring forceB. InertiaC. Gravitational potential energyD. Elastic potential energy EXPLANATIONTo get oscillations, a body is pulled away from its rest or equilibrium position and then released. The body oscillates due to a restoring force. Under the action of this restoring force, the body accelerates and it overshoots the rest position due to inertia. QUESTION: _________ relationship exists between current and voltage in terms of Ohms law.A. Non-linearB. VaryingC. LinearD. None of these options is correct EXPLANATIONOhms law defines the relationship between the voltage, current, and resistance in an electric circuit: I = V/R. Hence, the current is directly proportional to the voltage. QUESTION: Which of the following is made up of more neutrons than protons?A. HB. OC. UD. None of these options is correct EXPLANATIONThe nucleus of Hydrogen is made up of 1 proton and 0 neutrons.The nucleus of Oxygen is made up of 8 protons and 8 neutrons.The nucleus of Uranium is made up of 92 protons and 146 neutrons. Therefore, the Uranium nucleus is made up of more neutrons than protons. QUESTION: The black body always _______ radiations.A. EmitsB. AbsorbsC. Both Option A and B are correctD. Reflects EXPLANATIONA black body is an idealized object that absorbs all electromagnetic radiation it comes in contact with. It then emits thermal radiation in a continuous spectrum according to its temperature. Black bodies do not reflect light - reflection and emission are two different concepts. Emission refers to the generation of photons from the same source that absorbs them, while Reflection refers to the scattering of photons that come from some other source. QUESTION: An electrical instrument which is used to measure the potential difference between two points is called the:A. BarometerB. ManometerC. GalvanometerD. Voltmeter EXPLANATIONA voltmeter is an instrument used for measuring the electrical potential difference between two points in an electric circuit. The voltmeter has a very high resistance and is connected in parallel to the electrical component whose potential difference is to be measured. QUESTION: The frequency of applied AC is 2 kHz. Its time period will be:A. 0.5 x 10-3 secB. 0.5 secondC. 5 secD. 2 sec EXPLANATIONFormula: Frequency = 1/t t = 1/2000 = 0.5 x 10-3 sec QUESTION: Velocity is a: A. TensorB. VectorC. ScalarD. None of these options is correct EXPLANATIONVelocity is a vector quantity β it is the speed of an object in a particular direction. A quantity that has magnitude and acts in a particular direction is described as a vector. QUESTION: The effect of work done is equal to?A. Change in total energyB. Change in kinetic energyC. Change in powerD. None of these options is correct EXPLANATIONThe work-energy theorem states that the net work done by the forces on an object equals the change in its kinetic energy. The net work done on a particle equals the change in the particles kinetic energy: QUESTION: The electron volt is the unit of __________.A. Electric currentB. Electric potentialC. Electric energyD. Electric flux EXPLANATIONAn electron volt is a unit of electric energy equal to the work done on an electron in accelerating it through a potential difference of one volt. Other units of electric energy are erg and Joules. QUESTION: Which of the following frequency of sound wave is audible?A. 5 HzB. 5000 HzC. 2500 kHzD. 50 kHz EXPLANATIONHumans can detect sounds in a frequency range from about 20 Hz to 20 kHz. (Human infants can actually hear frequencies slightly higher than 20 kHz, but lose some high-frequency sensitivity as they mature; the upper limit in average adults is often closer to 15β17 kHz.) QUESTION: The rectifier is a device which converts?A. AC to DCB. DC to ACC. AC to triangular currentD. DC to triangular current EXPLANATIONA rectifier is a device that converts an oscillating two-directional alternating current (AC) into a single-directional direct current (DC). Rectifiers can take a wide variety of physical forms, from vacuum tube diodes and crystal radio receivers to modern silicon-based designs. QUESTION: The value of the universal gas constant, R, is __________?A. 8.314 J/mol x KB. 1.38 x 10-23 J/KC. 6.63 x 10-11 Nm2/kg2D. 1.6 x 10-19 C EXPLANATIONThe dimensions of the universal gas constant R are energy per degree per mole. In the meter-kilogram-second system, the value of R is 8.3144598 joules per kelvin (K) per mole. QUESTION: Which of the following is different for isotopes?A. NeutronsB. ProtonsC. ElectronsD. All of these options are correct EXPLANATIONAll isotopes have the same number of protons and the same number of electrons. The difference in the ratio between the number of protons (the number of protons stays the same) and the number of neutrons creates a difference in the nuclear reactions of the isotopes. QUESTION: What is the maximum electron energy in a neutron beta-decay?A. 783 eVB. 783 keVC. 783 GeVD. 783 Tev EXPLANATIONBeta-decay occurs when, in a nucleus with too many protons or too many neutrons, one of the protons or neutrons is transformed into the other. In beta-minus decay, a neutron decays into a proton, an electron, and an antineutrino. The maximum electron energy in neutron beta-decay hence is 783kev. QUESTION: Protons and neutrons are composed of smaller particles called:A. QuarksB. BaryonsC. BosonsD. Photons EXPLANATIONQuarks make up protons and neutrons, which, in turn, make up an atoms nucleus. Each proton and each neutron contains three quarks. A quark is a fast-moving point of energy. QUESTION: A loop of radius 1 m is placed on an incline of 60Λ with a magnetic field of 100 T. The corresponding flux will be:A. 314 WbB. 107 WbC. 157 WbD. 435 Wb EXPLANATIONMagnetic flux formula: flux = BACos(ΞΈ) B = Magnetic Field A = area Angle = angle between a perpendicular vector to the area and the magnetic field Ξ¦ = 100ΓΟΓ 1Β²Γ cos(60Β°) = 100Γ3.14Γ1Γ0.5 = 157 QUESTION: An air pipe is open at one end. A stationary wave is produced in second harmonic mode. What is the phase difference between the motion of the particles at the closed end of the pipe and at the centre of the pipe.A. 0Β°B. 90Β°C. 180Β°D. 270Β° EXPLANATIONPhase difference between moving particles at the end and center of the pipe will be 180 degree. QUESTION: Activity of a radioactive substance changes from 8000Bq to 1000Bq in 12 days. What is the half-life of the radioactive substance?A. 4 daysB. 6 daysC. 2 daysD. 3 days EXPLANATIONFollowing is the explanation to this solution. QUESTION: Coherent source of light means?A. Multiple wavelengthsB. Double wavelengthC. Single wavelengthD. Coherent photons EXPLANATIONCoherent sources of light are those sources which emit a light wave having the same frequency, wavelength and in the same phase or they have a constant phase difference. A coherent source forms sustained interference patterns when superimposition of waves occur and the positions of maxima and minima are fixed. QUESTION: In a spectrometer, the circular scale, graduated in half degree, is attached with:A. TelescopeB. TurntableC. Cross wire of telescopeD. None of these options is correct EXPLANATIONThe turntable is the major part of the instrument. It is mounted with a robust bearing, and it can be rotated around a vertical axis. It is provided with a circular scale marked from 0 to 360Λ at 0.5Λ intervals. QUESTION: The maximum efficiency of a half-wave rectifier is:A. 80.6 %B. 40.6 %C. 70 %D. 50 % EXPLANATIONThe maximum efficiency of a half-wave rectifier is about 40.6 %, and the maximum efficiency of a full-wave rectifier is twice that. QUESTION: Two identical gasses expand: i) Isothermally ii) Adiabatically Work done is more in the:A. Isothermal processB. Adiabatic processC. Neither of these casesD. Equal in both cases EXPLANATIONIn an isothermal process, ΞW = ΞQ - ΞU In an adiabatic process ΞW = ΞQ - ΞU As ΞQ = 0 ΞW = -ΞU Therefore, more work is done in the isothermal process. QUESTION: The source of gamma radiation is?A. Outside the nucleusB. Inside the nucleusC. Electron transitionD. None of these options is correct EXPLANATIONGamma rays are produced in the disintegration of radioactive atomic nuclei and in the decay of certain subatomic particles. QUESTION: If a proton, alpha particle, and photon moving with the same velocity enter a uniform magnetic field, then which particle will deflect more?A. ProtonB. Alpha particleC. PhotonD. All of these options are correct EXPLANATIONThe photon is electrically neutral and thus will not deflect in a magnetic field. Between the proton and alpha particle, the alpha particle has a greater mass so its acceleration, and therefore the radius of the path that it traces, will be less than that of the proton. A smaller radius means a smaller deflection. QUESTION: A cubic vessel of height 1 m is full of water. The minimum work done in taking the water out is:A. 5000 JB. 10000 JC. 5 JD. 10 J EXPLANATIONTotal water volume = 1m Γ 1m Γ 1m = 1m3So massΒ = 1m3 Γ m31000Β kg β= 1000Β kgheightΒ =1mSo centre of mass will be at aΒ distance of 1/2=0.5Β mΒ from groundSo potential energyΒ =mgΓ0.5=1000Γ10Γ0.5=5000Β J QUESTION: Woolen clothes keep the body warm because of:A. Bad conductivityB. Good conductivityC. Low temperatureD. None of these options is correct EXPLANATIONSince air is a bad conductor of heat, it prevents the loss of heat from the body, thus keeping it warm. The wool in itself is a bad conductor of heat and does not allow heat generated by the body to leave and insulates the body well. QUESTION: The open-circuit test in a transformer is used to measure?A. Copper lossB. Winding lossC. Total lossD. Core loss EXPLANATIONThe open-circuit test is done to find the core loss of the transformer. It is done by keeping one of the windings open (without load, usually the high voltage winding is open) and applying rated voltage to the other winding (usually the low voltage winding because it is easier to apply rated voltage). QUESTION: Frequency of a travelling wave is 2000 Hz. Its speed is 300m/s. What is its wavelength?A. 20/3 mB. 20x3 mC. 3/20 mD. 2/3 m EXPLANATIONWavelength formula = v/f Wavelength= 300/2000 = 3/2 QUESTION: Which statement is incorrect?A. In an isobaric process β³P = 0 B. In an isochoric process β³W = 0C. In an isothermal process β³T = 0D. In an isothermal process β³Q = 0 EXPLANATIONA is correct because in an isobaric process, the pressure of the system remains constant. B is correct because in an isochoric process, the volume remains constant, therefore no work is done by the system.C is correct because in an isothermal process, the temperature of the system remains constant. The transfer of heat into or out of the system happens so slowly that thermal equilibrium is maintained and ΞT = 0. D is incorrect because the net heat flow into the system (ΞQ) is not zero in an isothermal process. In an adiabatic process, there is no transfer of heat into or out of the system. (ΞQ = 0) QUESTION: The engine is supposed to work between 727Β°C and 227Β°C, then the maximum possible efficiency is:A. 1/2B. 1/4C. 3/4D. 1 EXPLANATIONT1 = 727 + 273 = 1000 K T2 = 227 + 273 = 500 K Efficiency of engine = Ξ· = 1 β (T2 / T1) β΄ Ξ· = 1 β {(500) / (1000)} Ξ· = Β½ QUESTION: The correct form of ohms law is:A. I = VRB. V β IC. V = IRD. Both Options B and C are correct EXPLANATIONOhms law may be expressed mathematically as V/I = R. That the resistance, or the ratio of voltage to current, for all or part of an electric circuit at a fixed temperature is generally constant. QUESTION: If the instantaneous current in a circuit is given by I = A sin (wt) ampere, the RMS value of the current is:A. 2AB. A/β2C. 2β2AD. Zero EXPLANATIONWe know that RMS = I(peak)/β2Ipeak is basically the amplitude of the graph represented by the equation l = Asin(wt). Here A is the amplitude of the graph and also the peak current value. Therefore: I(rms) = A/β2 QUESTION: If we are moving with a constant velocity frame, then the inertial state is same as the:A. Rest frameB. Accelerating frameC. Non-inertial frameD. All of these options are correct EXPLANATIONAn object moves at constant velocity unless acted upon by an external force. In such a frame, an object is observed to have no acceleration when no forces are acting on it. If a reference frame moves with constant velocity relative to an inertial reference frame, it also is an inertial reference frame. QUESTION: An object is moving at constant speed, which of the following is always true:A. Distance is greater than the displacementB. Distance is lesser than the displacementC. Distance is equal to the displacementD. There is not enough information available EXPLANATIONFor a moving object, the distance covered by it is always greater than or equal to the displacement of the object in a given time interval. QUESTION: When a spring is stretched, the work done by the stretching force is?A. PositiveB. Negative C. ZeroD. None of these options is correct EXPLANATIONIf a spring is stretched, then the direction of the applied force and the direction of displacement are the same. And the angle between the force and the displacement is zero, which results inΒ positive workΒ done by the stretching force. QUESTION: You have three capacitors, each of 2 Β΅C. In which of the following combinations of the three capacitors, is the resultant capacitance 6Β΅C?A. All three capacitors in seriesB. Two capacitors are in series, one in parallelC. Two capacitors are in parallel, one in seriesD. All three capacitors in parallel EXPLANATIONWhen capacitors are connected in parallel, the equivalent capacitance is the sum of the individual capacitances. QUESTION: The use of a capacitor filter in a rectifier circuit gives satisfactory performance only when the load:A. Current is highB. Current is lowC. Voltage is highD. Voltage is low EXPLANATIONCapacitor filter in rectifier circuit gives satisfactory performance only when the load resistance value is large. If the load resistance is large, then the discharge time is large and the rectifier circuit gives satisfactory performance. As the load is large, the load current is low. QUESTION: An object is displaced from point A (0, 1, 1) m to point B (1, 4, 3) m under a constant force F = (i + 2j +3k). Find the work done by this force in this process:A. 13 JB. 15 JC. 0 JD. 14 J EXPLANATIONF= i + 2j + 3k Displacement =D= (i + 4j + 3k) - (j + k) = i + 3j + 2k Work = F x D = (i +2j + 3k) x (i + 3j + 2k) = 1 + 6 + 6 = 13 QUESTION: When the bulb is turned on, ohms law is applicable:A. YesB. NoC. PartlyD. None of these options is correct EXPLANATIONThe resistance of a filament lamp or bulb changes with the temperature of the filament as the potential across it increasesΒ and this means it is non-Ohmic. QUESTION: A wave passes through a medium; each particle of the medium performs 100 complete vibrations in 5 seconds. What is the frequency of the wave?A. 2 HzB. 20 HzC. 4 HzD. 40 Hz EXPLANATIONFrequency is the number of vibrations per second. 100/5 = 20 QUESTION: Identify the factor on which mutual inductance does not depend:A. Relative orientationB. Relative separation of two coilsC. ReciprocityD. Permeability of the core material EXPLANATIONThe mutual inductance of two coils is the property of their combination. It does not matter which one of them functions as the primary or the secondary coil. Hence, mutual inductance does not depend on reciprocity. QUESTION: What force provides the centripetal force to planets moving around the sun?A. Coulombs forceB. Gravitational forceC. Magnetic forceD. None of these options is correct EXPLANATIONIn the case of an orbiting planet, the force is gravity. The gravitational attraction of the Sun is an inward (centripetal) force acting on Earth. This force produces the centripetal acceleration of the orbital motion. QUESTION: Electrostatic force is?A. Non-conservativeB. ConservativeC. Depends on the shape of the chargeD. None of these options is correct EXPLANATIONThe electrostatic or Coulombs force is conservative, which means that the work done on q is independent of the path taken. This is exactly analogous to the gravitational force. When a force is conservative, it is possible to define potential energy associated with the force. QUESTION: A beam of electrons can:A. ReflectB. RefractC. Both Options A and B are correctD. None of these options is correct EXPLANATIONA beam of electron can both reflect and refract from surfaces. QUESTION: A stationary wave is set up on a string of length 10 cm. Four loops are formed. What is the distance between two consecutive crests?A. 4.5 cmB. 5 cmC. 2.5 cmD. 1.25 cm EXPLANATIONThe distance between the two successive nodes or two successive antinodes in a specific stationary wave is half of the wavelength. So the distance between 4 loops is 0.5 + 0.5 + 0.5 + 0.5 + 0.5 = 2.5. QUESTION: A galvanometer acting as a voltmeter will have a coil with?A. A high resistance in parallelB. A high resistance in seriesC. A low resistance in parallelD. A low resistance in series EXPLANATIONThe resistance of the coil of the galvanometer of its own is low, hence to convert a galvanometer into a voltmeter, its resistance is to be increased. For this, an appropriate high resistance is joined in series with the galvanometer. QUESTION: The centripetal force is zero when the centrifugal force is:A. EqualB. ZeroC. MaximumD. None of these options is correct EXPLANATIONCentrifugal force is felt only when there is a centripetal force, so the centripetal force is zero when the centrifugal force is zero. QUESTION: A cyclist comes to a skidding stop in 10 m. During this process, the force on the cycle due to the road is 200 N and is directly opposed to the motion. How much work does the road do on the cycle? How much work does the cycle do on the road?A. -2000 J, 2000 JB. -2000 J, 1000 JC. 0 J, 2000 JD. -2000 J, 0 J EXPLANATIONWork done by the road = -200 x 10 = -2000J As the road does not move at all, (displacement=0), the work done by the cycle on the road is 0. QUESTION: A 100 W heater is used for 5 minutes to heat some water from 20ΛC to 50Β°C. What is the mass of water which is heated? The specific heat capacity of water is 4.2 J/gΒ°CA. 4 gB. 40 gC. 240 gD. 24 g EXPLANATIONExplanation for this question is given below: QUESTION: If the clouds of the Earth behave like a black body, what will happen: A. No light will reach the surfaceB. Extra light will reach the surfaceC. Nothing will happenD. Some light will reflect, some will be absorbed EXPLANATIONIf Earths clouds were perfect black bodies, then they would absorb the sunlight falling on them and radiate that energy as heat. The heat would reach the surface of Earth and the oceans, causing more clouds to form by the process of evaporation, followed by condensation. More clouds would eventually result in no light reaching the Earths surface. QUESTION: The negative of the potential gradient is equal to:A. Electric field intensityB. Electric fluxC. Magnetic intensityD. Magnetic flux EXPLANATIONW = Fd F = qE W = qEd W/q = V = Ed V/d = E While the magnitude of the electric field is equal to the gradient of the electric potential, the electric field points in the opposite direction of the gradient of the electric potential, hence the negative sign. QUESTION: Mass m1 has a velocity of 0m/s and mass m2 has a velocity of 5 m/s; m1>m2. Which one has a larger interior?A. m2 B. m1C. Both m1 and m2D. Not enough information is available EXPLANATIONInterior means volume. Speed and mass alone dont give us enough data to determine the volume. QUESTION: A pendulum undergoes simple harmonic motion. The phase difference between the displacement and the acceleration of the particle is: A. 0B. Ο/2C. ΟD. 3Ο/2 EXPLANATIONAcceleration and displacement are always opposite to each other and hence completely out of phase. Therefore, the answer is Ο. QUESTION: As the mass number increases, which of the following does not change?A. MassB. DensityC. VolumeD. Binding energy EXPLANATIONAs the mass number A increases, this causes increase in the volume of nucleus, hence density remains constant. QUESTION: What is the power of a bulb if it is operated at 220V and the current in the circuit is 1.5 Amp?A. 330 WattB. 430 WattC. 530 WattD. 500 Watt EXPLANATIONPower = VI = 220 x 1.5 = 330 QUESTION: Motional EMF can be produced with:A. Changing magnetic field in spaceB. Changing magnetic field in timeC. Changing flux with spaceD. Constant magnetic field EXPLANATIONA motional EMF is the EMF induced in a conductor moving through a constant magnetic field. QUESTION: Statements:I. The literacy rate in the district has been increasing for the last four years.II. The district administration has conducted extensive training programme for the workers involved in the literacy drive.A. Statement I is the cause and statement II is its effectB. Statement II is the cause and statement I is its effectC. Both statements I and II are independent causesD. Both statements I and II are effects of some common cause EXPLANATIONAs the district administration has conducted an extensive training programme for the workers involved in the literacy drive, therefore, the literacy in the district has been increasing for the last four years. QUESTION: Look at this series 14, 28, 20, 40, 32, 64. What number should come next?A. 52B. 56C. 96D. 128 EXPLANATIONThis is the alternating multiplication and subtracting series: First, multiply by 2 and then subtract 8. For example 14 Γ 2 = 28 and then 28 β 8 = 20. QUESTION: CMM, EOO, GQQ, _____, KUUA. GRRB. GSSC. ISSD. ITT EXPLANATIONThe first letters are in alphabetical order with a letter skipped in between each segment: C, E, G, I, K. The second and third letters are repeated; they are also in order with a skipped letter; M, O, Q, S, U. QUESTION: Statement:The availability of imported fruits has increased in the indigenous market and so the demand for indigenous fruits has been decreased.Courses of Action:I. To help the indigenous producers of fruits, the Government should impose high import duty on these fruits, even if these are not of good quality.II. The fruit vendors should stop selling imported fruits. So that the demand for indigenous fruits would be increased.A. Both the courses of actions followB. None of the courses of actions followC. Only course of action I followsD. Only course of action II follows EXPLANATIONThe ideas suggested in both course of actions I and II represent unfair means to cut competition. The correct way would be to devise methods and techniques such that the indigenous producers could produce better quality fruits and make them available in the market at prices comparable with those of the imported ones. Hence, neither I nor II follows. QUESTION: Statement The availability of imported fruits has increased in the indigenous market and so the demand for indigenous fruits has been decreased.I. To help the indigenous producers of fruits, the Government should impose high import duty on these fruits, even if these are not of good quality.II. The fruit vendors should stop selling imported fruits. So that the demand for indigenous fruits would be increased.A. Both of them followsB. None of them followsC. Only I followD. Only II follows EXPLANATIONThe ideas suggested in both I and II represent unfair means to cut competition. The correct way would be to devise methods and techniques such that the indigenous producers could produce better quality fruits and make them available in the market at prices comparable with those of the imported ones. Hence, neither I nor II follows. QUESTION: How many such pairs of letters are there in the word HISTORICAL which have as many letters between them in the word as they have between them in the English alphabet?A. FourB. SevenC. FiveD. Eight EXPLANATION1- s & t (1) 2-h & i (1) 3-t & r (2) 4- i & i (2) 5- a & i (7) 6- s & i (6) 7- h & i (6) QUESTION: Statement:I. Police resorted to lathi-charge to disperse the unlawful gathering of large number of people.II. The citizens forum called a general strike in protest against the police atrocities.A. Statement I is the cause and statement II is its effectB. Statement II is the cause and statement I is its effectC. Both statements I and II are independent causesD. Both statements I and II are effects of independent causes EXPLANATIONThe peoples mass protest against the police might have instigated the latter to indulge in lathi-charge to disperse the mob. QUESTION: A book cannot exist without?A. EducationB. PicturesC. PagesD. Qualification EXPLANATIONA book can still exist if it doesnβt have pictures, it can be a reading book without pictures, it might be a book to read for leisure and not for education and it might not have any qualifications but it will still be a book. However, without pages, a book can physically not exist. QUESTION: Statement:I. There has been a decline in the prices of personal computers.II. School going kids are expressing interests in learning how the computer operates.A. Statement I is the cause and statement II is its effectB. Statement II is the cause and statement I is its effectC. Both statements I and II are independent causesD. Both statements I and II are the effects of independent cause EXPLANATIONBecause the use of computers for personal use has died over the years, and maybe due to that there has been a decline in their prices. The second statement states that students are interested in the operation of computers due to XYZ reasons and it is in no way linked to the first statement. The first statement is talking about the change in the price of computers. QUESTION: Discernible and Palpable have _________ letters in common. A. 2B. 3C. 5D. 4 EXPLANATIONBoth words have b, l, and e in common. Quote Link to comment Share on other sites More sharing options...
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