PMC Paid Practice Tests Series 2021 With Explanation - Test 31

[Shahid]

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: The sun _____ in the west
A. Rise
B. Rises
C. Rose
D. Risen
EXPLANATION
The movement of the sun is continuous hence motion should be described in a continuous tense. ‘Rise is grammatically incorrect when the sentence is said out loud and ‘rose’ and ‘risen are in the past tense. Hence ‘rises’ which is the continuous tense is correct.

QUESTION: Let me _____ the candle from the cake.
A. Switch off
B. Blow out
C. Extinguish
D. Eliminate
EXPLANATION
Switch-off means stopping the flow or operation of something by means of a tap, switch, or button. A candle does not operate via switch hence incorrect.  Blow out means being extinguished by an air current. This is correct as candles are unlightened by the strong passage of air.  Extinguish means putting an end to; destroying and, in this case, can be used in the context of a large flame, but not a candle.  Eliminate means completely remove or get rid of (something) which is incorrect in this case.

QUESTION: I had = _____
A. Id
B. Id
C. Id
D. lhd
EXPLANATION
Contractions are abbreviations of words blending together. Combining I and had, removing h and a, and using an apostrophe at where the letters are removed will form I’d.

QUESTION: Father must _____ left his briefcase at the office.
A. Of
B. Had
C. Have
D. Opt
EXPLANATION
Have is used to express possession, ownership, or acquisition which is required in this context hence correct.  ‘Of’ is used to show ownership or a distance from something or a result coming from something. As the sentence is not in a third person singular, ‘has’ is not used. ‘Are’ is used for plural nouns which is not the case in this sentence (Father is singular). Have is used with the pronouns I, you, we, and they, while ‘has is used with he, she, and it.  ‘Opt’ is used to make a choice, especially of one thing or possibility instead of others. In this case, the briefcase is an essential item and is necessary.

QUESTION: Father _____ me not to go out in the cold.
A. Adviced
B. Advice
C. Advise
D. Advised
EXPLANATION
‘Advised’ and ‘advice’ are nouns meaning, “an opinion or recommendation offered as a guide to action, conduct”, hence incorrect.  ‘Advise’, which is a verb that means, “to give counsel to and in this case advised, is more grammatically correct.

QUESTION: Choose the correct spelling of the word:
A. Disappeared
B. Disapeared
C. Disapared
D. Dissappeared
EXPLANATION
The other words are incorrect in terms of different meanings and spellings.

QUESTION: Choose the correct sentence:
A. I completed the homework for English, History, Math and Science only in the span of an hour.
B. I completed the homework for English History, Math, and Science only in the span of an hour!
C. I completed the homework for english, history, math, and science only in the span of an hour.
D. I completed the homework for English History Math and Science only in the span of an hour.
EXPLANATION
The sentence is not exclamatory hence cannot end with an exclamation mark and should end with a full stop. English, History, Maths and Science are proper nouns hence capitalised. Lastly, commas are used as a list of subjects are mentioned.

QUESTION: Which tense would you use for talking about your daily routine?
A. Present
B. Past
C. Future
D. None of these options are correct
EXPLANATION
Daily routine is an action which one does presently and continuously hence present tense should be used.

QUESTION: Choose the correct sentence:
A. Ariel is trying hard in school this semester, her father said.
EXPLANATION
Using accurate punctuation in quoting dialogues as well as the understanding type of sentences (declarative) is imperative. Understanding the commas position before ending quotation marks is essential.

QUESTION: Sara denied _____ the car window open.
A. Leave
B. Leaving
C. Left
D. To have left
EXPLANATION
‘Leaving’ is in a continuous tense which is accurate in this case.  Leave’ in this case is grammatically incorrect while ‘left and ‘to have left are in past tense and do not make grammatical sense when the sentence is said out loud.

QUESTION: He is very _____, he believes everything.
A. Fallible
B. Sensible
C. Credible
D. Gullible
EXPLANATION
Fallible means capable of making mistakes or being wrong. Sensible means have done or chosen in accordance with wisdom or prudence. Credible means able to be believed; convincing. Gullible means easily persuaded to believe something; credulous. In this case, as the sentence mentions that he believes everything, the adjective closely associated with its meaning is gullible.

QUESTION: We still havent come _____ with an interesting theme for the advertising campaign.
A. On
B. In
C. Up
D. Down
EXPLANATION
On is concerned with shorter, more specific periods of time. Down is used as a preposition (followed by a noun) and after the verb to be.  In is directly related to positions and longer periods of time, which in this case cannot be used.  Up, however is an adverb used to talk about moving towards a higher position, value, number or level hence it is correct.

QUESTION: Neither the professor nor his assistants _____ able to solve the mystery of the eerie glow in the laboratory.
A. Is
B. Was
C. Were
D. Be
EXPLANATION
‘Is is used when the noun is singular which is incorrect in this case as assistants is plural. ‘Was’ is a past tense indicative form of ‘be’, meaning “to exist or live,” and is used in the first person singular (I) and the third person singular (he/she/it). It is used as the past indicative when one is talking about reality and known facts. Be is commonly used in joining a subject to its complement. As a main verb, be is used to talk about feelings and states.  ‘Were’ is used in the second person singular and plural (you, your, yours) and first and third person plural (we, they). As the sentence is in third person plural (talking about the professor and assistant and as assistants” used) hence were is correct.

QUESTION: What did you want to do that _____?
A. Reason
B. For
C. Because
D. Thing
EXPLANATION
‘Reason’ is grammatically incorrect as it is used before a clause. ‘For’’ could be used for talking about vague periods of time and talking about the past, present, or future hence it is correct. ‘Because’ is used to express the reason or cause of something.  ‘Thing’ refers to physical objects but is also used to refer to ideas, actions, and events.

QUESTION: Which tense would you use for describing next years holiday?
A. Present
B. Past
C. Future
D. None of these options are correct
EXPLANATION
As next years holiday is an event that will take place in the future, future tense should be used.

QUESTION: He was dismissed from the service for his insistent _____.
A. Alertness
B. Nobility
C. Disobedience
D. Alliance
EXPLANATION
Alertness means the quality of being alert, vigilant. Nobility means the quality of being noble in character, virtue.  Disobedience means failure or refusal to obey rules or someone in authority. Alliance means a relationship based on similarity of interests, nature, or qualities. For one to be dismissed from a service negative characteristics are usually associated with the reason and behavior, hence disobedience is the most appropriate option.

QUESTION: Choose the correct sentence:
EXPLANATION
Using accurate punctuation in quoting dialogues as well as understanding the type of sentences (it is a declarative sentence) is imperative. Understanding the commas position before quotation marks is essential and the periods position inside.

QUESTION: Everything _____ fine when its done correctly.
A. Work
B. Worked
C. Will work
D. Works
EXPLANATION
‘Worked’ is past tense and ‘will work is future tense hence incorrect. ‘Work’ doesnt make grammatical sense. ‘Work’ implies all of it, and ‘works implies that one has some particular pieces in mind.

QUESTION: _____ man is mortal.
A. A
B. An
C. The
D. no article
EXPLANATION
The indefinite article ‘a is used before noun phrases when the noun or adjective that comes next begins with a consonant sound (incorrect in this case). ‘An is used when the noun or adjective that comes next begins with a vowel sound (incorrect).  In this sentence as a specific object/article is not concerned, “the” should not be used.

QUESTION: We missed our plane because we were late. What kind of sentence is this?
A. Complex
B. Simple
C. Compound
D. Compound-complex
EXPLANATION
As the sentence has at least two independent clauses and at least one dependent clause, it is a compound-complex sentence.  A sentence with one independent clause with no dependent clauses is a simple sentence.  A complex sentence has an independent clause and at least one dependent clause.  A compound sentence has at least two independent clauses.  Here, the two independent clauses are We missed our plane and we were late joined by the conjunction because

QUESTION: Population growth is checked by which of the following?
A. No competition
B. No polymorphism
C. Polymorphism
D. Competition
EXPLANATION
Competition among population makes organisms that are better adapted survive and reproduce, others die. As a result, there is a check and balance among the organisms .

QUESTION: In biennials and perennials, low temperature stimulus is not received by which of the following?
A. Shoot apex of mature stem
B. Embryo of the seed
C. Leaves of the plants
D. All of these
EXPLANATION
Whenever vernalization occurs in the mature plants, the receptor of stimulus is the stem apex. In other words, the meristematic cells in the bud respond to the cold treatment.

QUESTION: Which of the following cytoskeletal fibers contain tubulin protein?
A. One which forms the assembly of spindles during mitosis
B. One involved in internal cell motion
C. One involved in maintenance of cell shape
D. All of the above options are correct
EXPLANATION
Microtubules contain the protein tubulin. Option A is correct as during mitosis long protein fibers called microtubules extend from the centrioles in all possible directions, forming what is called a spindle. Option B and C are correct as microtubules are a part of the cytoskeleton of the cell. The cytoskeleton is a structure that helps cells maintain their shape and internal organization, and it also provides mechanical support that enables cells to carry out essential functions like division and movement. Therefore, Option D is the correct answer.

QUESTION: What is the size of Parvovirus?
A. 200nm
B. 20nm
C. 300nm
D. 350nm
EXPLANATION
Parvovirus is one of the smallest viruses, it causes disease in dogs.

QUESTION: Which theory tells about adaptation?
A. Darwins natural selection
B. Lamarcks theory
C. Weinbergs principle
D. Hardy
EXPLANATION
Darwin’s natural selection talks about the “survival of the fittest” theory saying organisms that are better adapted, survive and pass on their advantageous genes.

QUESTION: Which of the following structure primarily helps in attachment of bacteria on various surfaces?
A. Pilli
B. Flagella
C. Both A and B
D. None of these
EXPLANATION
Flagella help in locomotion whereas pilli help in attachment.

QUESTION: The shape of grey matter is _____.
A. Spherical
B. Butterfly
C. Mosquito
D. Rectangular
EXPLANATION
Spinal gray matter is butterfly-shaped.

QUESTION: The main target in the prevention of lung cancer is eliminating the _____.
A. Tobacco smoking
B. Chemicals
C. Pollutants
D. Mutagens
EXPLANATION
Smoking has carcinogens that cause mutations and alter cell death, causing uncontrolled mitotic divisions.

QUESTION: A chemical component that is NOT found in all viruses is _____.
A. Protein
B. Lipids
C. DNA
D. RNA
EXPLANATION
Lipid envelope is the chracteristic of only some viruses, who also gain it by their host cells after they cause it to burst. The only necessary features in all viruses are protien coat and nucleic acids.

QUESTION: The bond formed when two or more atoms complete their electron shells by sharing electrons is called _____.
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. None of these options are correct
EXPLANATION
Covalent bonding has a characteristic feature which involves the sharing of electrons between to two non-metal atoms.

QUESTION: The substrate concentration that produces exactly half of the maximum reaction rate can be described by?
A. Michaelis equation
B. Menten equation
C. Bernoulli equation
D. Michaelis-Menten equation
EXPLANATION
Michaelis-Menten equation or the Km value shows the concentration required for half of the Vmax.

QUESTION: The lighter, inner section of the brain is called:
A. White matter
B. Gray matter
C. Reflex arc
D. Medulla
EXPLANATION
Brain has inner section white, made of axons whereas the spinal cord has inner section gray made of cell bodies.

QUESTION: In non-competitive inhibition, the extent of inhibition depends only on the _____.
A. Concentration of enzyme
B. Concentration of substrate
C. Concentration of ES complex
D. Concentration of inhibitor
EXPLANATION
Non-competetive inhibition is when the inhibitor binds to the enzyme, so the extent of inhibition only depends on the concentration of inhibitor.

QUESTION: Higher turgor pressure in a plant cell is maintained by _____.
A. Higher ionic concentration inside vacuoles
B. Higher osmotic pressure of the cell vacuole
C. Large number of vacuoles in a plant cell
D. Both a and b
EXPLANATION
Higher ionic concentration means water does not leave the vacuole, and the higher osmotic pressure of vacuole means the vacuole will push the cell membrane, producing pressure and higher turgor of the plant cells that helps keep the plant steady.

QUESTION: Where the heterozygote is indistinguishable from one of the homozygotes the allele involved is said to be?
A. Recessive
B. Dominant
C. Both A and B
D. None of these
EXPLANATION
In the dominant allele, in both homozygous and heterozygous form the genotype cannot be known as the phenotype in both is same.

QUESTION: Rate of photosynthesis does not depend upon _____.
A. Quality of light
B. Intensity of Light
C. Duration of Light
D. Temperature
EXPLANATION
Rate of photosynthesis does not depend on time, as it is per unit time.

QUESTION: The loss of liquid via the hydathodes is called _____.
A. Ascent of sap
B. Plasmolysis
C. Imbibition
D. Guttation
EXPLANATION
In guttation the loss of water occurs in the form of the dilute solution which consists of salts and minerals through hydathodes.

QUESTION: Urethra and vagina have _____ openings to the exterior.
A. Common
B. Independent
C. Both A and B
D. None of these
EXPLANATION
The female reproductive and excretory system have different opening. However, in males the opening is the same.

QUESTION: The most common cause of cancer-related deaths is _____.
A. Prostate cancer
B. Kidney cancer
C. Lung cancer
D. Skin cancer
EXPLANATION
Lung cancer has the highest mortality.

QUESTION: What type of bonds exist between an enzyme and its prosthetic group?
A. Ionic
B. Covalent
C. Hydrogen
D. Metallic
EXPLANATION
If the cofactor is permanently bonded using covalent bonds, it is called prosthetic group.

QUESTION: Which of the statements correctly describes why ions are unable to cross the plasma membrane without channel proteins?
A. They are unable to cross the hydrophilic-phosphate heads of the lipid bilayer
B. They are unable to cross the hydrophobic tails of the lipid bilayer
C. They are unable to cross both the phosphate heads and fatty acid chains of the lipid bilayer
D. They are too big to cross the plasma membrane
EXPLANATION
Ions are charged and thus are repelled by the hydrophobic interior of membrane made by the phospholipid tails. Channel protein provide a hydrophilic channel for the hydrophilic ions to pass.

QUESTION: The phenomenon in which the effect of one allele in a heterozygous genotype completely masks the effect of the other is called _____.
A. Codominance
B. Dominance
C. Incomplete dominance
D. Complete dominance
EXPLANATION
When the phenotype represents only the effect of the dominant, no sign of recessive phenotype, then there is complete dominance of the dominant allele.

QUESTION: For every 3 molecules of carbon dioxide in Calvin cycle how much G3P is produced?
A. 6
B. 5
C. 3
D. 8
EXPLANATION
An enzyme, RuBisCO, catalyzes the fixation reaction, by combining CO2 with RuBP. The resulting six-carbon compound is broken down into two three-carbon compounds, and the energy in ATP and NADPH is used to convert these molecules into G3P.

QUESTION: The process of self-digestion of selective non functional organelle by cells through the actions of enzymes originating from the cell is called _____.
A. Pinocytosis
B. Endocytosis
C. Autophagy
D. Cytotoxicity
EXPLANATION
Autophagy is known as self-digestion, hydrolytic enzymes in lysosomes are responsible for it.

QUESTION: Primordial soup is a set of hypothetical conditions on ancient earth first proposed by?
A. Dmitri lvanovsky
B. Dmitry Anuchin
C. Nikolay Shatsky
D. Alexander Oparin
EXPLANATION
The primordial soup is a generic term that describes the aqueous solution of organic compounds that accumulated in primitive water bodies of the early Earth.

QUESTION: The follicle cells, after release of the egg, are modified to form a special structure called _____.
A. Corpus luteum
B. Endometrium
C. Perimetrium
D. None of these
EXPLANATION
The corpus luteum after ovulation releases hormones oestrogen and progesterone that help maintain lining of uterus for fertilization.

QUESTION: The oldest mineral discovered so far is which of the following, which dates back to 4.4 billion years:
A. Iron
B. Zircon
C. Diamond
D. Cadmium
EXPLANATION
Zircon is the oldest mineral discovered. It is used to make jewellery.

QUESTION: The bronchitis is of _____ types.
A. 3
B. 2
C. 5
D. 6
EXPLANATION
The two types of bronchitis are acute and chronic bronchitis.

QUESTION: Which of the following is not a viral disease?
A. Smallpox
B. Mumps
C. Tetanus
D. Cowpox
EXPLANATION
Tetanus is a bacterial disease caused by the bacteria, clostridium tetanus.

QUESTION: Viruses can bud from _____.
A. Rough endoplasmic reticulum
B. Golgi complex
C. Nuclear envelope
D. All of these options are correct
EXPLANATION
Viruses can bud at every stage in the ER-Golgi-cell membrane pathway.

QUESTION: The brain part that carries sensory information to the limbic system and cerebrum is the _____.
A. Medulla
B. Thalamus
C. Hypothalamus
D. Corpus callosum
EXPLANATION
The thalamus is a small structure within the brain located just above the brain stem between the cerebral cortex and the midbrain and has extensive nerve connections to both. The primary function of the thalamus is to relay motor and sensory signals to the cerebral cortex.

QUESTION: The canal system in sponges develop due to which of the following?
A. Porous walls
B. Gastrovascular system
C. Reproduction
D. Folding of inner walls
EXPLANATION
Canal system is also known as aquiferous system. The canal system of sponges helps in food acquisition, respiratory gas exchange and also in excretion. It occurs by folding of inner walls to provide maximum surface area, as seen in the image below.

QUESTION: Which molecule passes the mitochondrial membrane to begin the krebs cycle?
A. ATP
B. ADP
C. NADH
D. Acetyl-CoA
EXPLANATION
Acetyl-CoA is the product of link reaction and enters the Kreb’s cycle. Where it combines with oxaloacetate and continues in the process of respiration.

QUESTION: Which of the statement is not true for compounds like glycoprotein and glycolipids?
A. They are conjugated molecules of carbohydrates
B. Both have role in the extracellular matrix of animals and bacterial cell wall
C. They are components of biological membranes.
D. Both are produced and screted by endoplasmic reticulum
EXPLANATION
Addition of sugars to protiens and lipids occurs in the golgi body, not in the endoplasmic reticulum.

QUESTION: Water vapor exits and CO2 enters a leaf through the _____.
A. Stomata
B. Grana
C. Porphyrin ring
D. Photons
EXPLANATION
Stomatal opening is the place where gaseous exchange occurs in the plant. Ater vapor from transpiration leaves the plant and CO2 for photsynthesis enters the plant through it.

QUESTION: Which viruses can convert normal cells into cancer cells?
A. Retrovirus
B. Adenovirus
C. Poliovirus
D. All of these
EXPLANATION
Retorvirus insert their DNA into the host DNA and several times they can insert the DNA in a way that the proto-oncogenes are converted into oncogenes and cancer occurs.

QUESTION: What are the most physiologically significant disaccharides?
EXPLANATION
Maltose is the immediate product of digestion of starch. Sucrose is the tranport sugar in plants. Lactose is the sugar present in milk. All are significant.

QUESTION: What is the correct sequence of steps in cell fractionation?
A. Homogenization, centrifugation, sepration
B. Separation, homogenization, centrifugation
C. Centrifugation, homogenization, separation
D. Homogenization, separation, centrifugation
EXPLANATION
First, the cells are homogenized, then they are spun at high speeds so that fractionation according to size can occur - this is called centrifugation, and then separation of the separated organelles by mass occurs.

QUESTION: Nephridia are the excretory organs of members of which phylum?
A. Arthropoda
B. Cnidaria
C. Annelida
D. Mollusca
EXPLANATION
Nephridia are the excretory organs present in annelids such as earthworm. Flatworms, cephalochordate, rotifers contain protonephridia or flame cells for osmoregulation.

QUESTION: The optimum pH for enzyme arginase is _____.
A. 9.3
B. 9.7
C. 10
D. 9
EXPLANATION
Arginse has maximum activity at pH9.7. It is a pancreatic enzyme and thus, works best in alkaline conditions.

QUESTION: What is the chemical characteristic of auxins?
A. lndole propionic acid
B. lndole carboxylic acid
C. lndole acetaldehyde
D. lndole acetic acid
EXPLANATION
Auxins plant growth hormones that are composed of indole acetic acid.

QUESTION: Which disease is represented by excess MSH secretion?
A. Addisons
B. Alzheimers
C. Parkinsons
D. Crohns
EXPLANATION
In Addisons disease, the adrenal glands do not produce enough hormones (including cortisol). As a consequence, the hypothalamus stimulates the pituitary gland to release more adrenocorticotropic hormone to try and stimulate the adrenal glands to produce more cortisol. The ADTH hormone can cause the excess secretion of MSH.

QUESTION: During the menstrual cycle, which of the following events happens if a released egg does not become fertilised?
A. The lining of the womb wall stays built up.
B. The lining of the womb wall builds up again.
C. Another egg is immediately released.
D. The lining of the womb wall breaks down.
EXPLANATION
If fertilization does not occur, the uterus wall breaks down, menstraution occurs and the body prepares for the next cycle.

QUESTION: What affect do enzymes have on the activation energy of a reaction?
A. Increases
B. Decreases
C. No affect
D. Increases or decreases depending upon individual enzyme
EXPLANATION
Enzymes decrease the activation energy and thus, increase the rate of a reaction.

QUESTION: The amount of oxygen in exhaled air is _____.
A. 21%
B. 16%
C. 79%
D. 4%
EXPLANATION
The amount of oxygen in exhaled air is 16% whereas in inhaled air it is 21% as the body absorbs oxygen for aerobic respiration to occur.

QUESTION: The fibrous connective tissue which attaches bone to bone is called _____.
A. Tendon
B. Ligament
C. Reticular tissue
D. Cartilage
EXPLANATION
Ligament attaches a bone with bone, whereas tendons attach bone with muscle; both are made of cartilage.

QUESTION: Lamarcks ideas on biological evolution contained correct and incorrect notions. Which of his ideas is correct?
A. Acquired traits can be passed on to offspring
B. Living forms become perfect with time
C. Nervous fluids are passed on from generation to generation
D. Evolution is related to changes in adaptation to the environment
EXPLANATION
Evolution occurs by passing down of advantageous traits that are more adapted to the environment of an area over many years.

QUESTION: How is the HIV virus transmitted?
A. Sexual contact
B. Blood
C. Breast feeding
D. All of the above
EXPLANATION
HIV virus is transmitted through body fluids, whether it is by sexual contact, blood or breastfeeding.

QUESTION: How is pyruvate produced in anaerobic conditions?
A. Alcoholic fermentation
B. Lactic acid fermentation
C. Respiration
D. Both A and B
EXPLANATION
Pyruvate is produced in both of the processes as glycolysis continues to occur even in the absence of oxygen.

QUESTION: The ETC in plants consists of an electron carrier called _____.
A. Pq
B. Pc
C. Pt
D. Po
EXPLANATION
Plastoquinone is an electron carrier abbreviated as Pq in plants respiratory system.

QUESTION: What was the source of hydrogen for first photosynthetic organisms?
A. Water
B. Hydrogen present in soil
C. Hydrogen sulphate
D. Hydrogen sulphide
EXPLANATION
Cyanobacteria are the first photosynthetic organisms. They used hydrogen sulfide as source of hydrogen.

QUESTION: Approximately how many species of bacteria are known to cause diseases in humans?
A. 100
B. 150
C. 200
D. 250
EXPLANATION
200 species of bacteria are pathogenic, i.e can cause disease like cholera and tuberculosis in humans.

QUESTION: Loss of lung tissue is caused by _____.
A. Emphysema
B. Asthma
C. Pneumonia
D. Bronchitis
EXPLANATION
Emphysema causes the alveoli to burst as a result lung tissue is lost.

QUESTION: Compared to gram negative bacteria, how many more membrane-bound organelles do gram positive bacteria contain?
A. 0
B. 1
C. 3
D. 2
EXPLANATION
Gram negative and gram positive bacteria contain the same number of membrane bound organelles.

QUESTION: What is a vestigial trait?
A. A trait that makes an organism better suited to a habitat
B. A structure that has origins in a common ancestor, but has evolved to perform different functions
C. A change to a cells genome
D. A structure that has lost its function but has been retained
EXPLANATION
Examples of vestigial structures include the human appendix, the pelvic bone of a snake, and the wings of flightless birds. They are present but have no apparent function.

QUESTION: Which one of the following animals is not a tetrapod?
A. Snake
B. Cow
C. Mantis shrimp
D. Human
EXPLANATION
Mantis shrimp is an arthropod not a tetrapod.

QUESTION: _____ is a common causative agent of genital herpes.
A. HSV-1
B. HSV-2
C. Both A and B
D. None of these
EXPLANATION
Genital herpes is a common sexually transmitted infection caused by the herpes simplex virus (HSV). Sexual contact is the primary way that the virus spreads. After the initial infection, the virus lies dormant in your body and can reactivate several times a year.

QUESTION: The difference in photosynthesis spectrum and actin spectrum occurs due to _____.
A. Carbon dioxide
B. Oxygen
C. Carotenoid
D. Wavelength
EXPLANATION
Carotenoids absorb wavelengths of light which are not used in photosynthesis, thus there is difference in absorption and action spectrum of photosynthesis.

QUESTION: Homozygous chromosomes include which of the following?
A. Diploid cells
B. Polyploid cells
C. Both A and B
D. None of these
EXPLANATION
In diploid and polyploid cells, more than one complete cells of chromosomes are present so homologous chromosomes can be formed.

QUESTION: Enzymes for light-dependent reactions of photosynthesis would most likely be associated with _____.
A. Outer membrane of the chloroplast
B. Inner membrane of the chloroplast
C. Strama of the chloroplast
D. Thylakoid membranes of the chloroplast
EXPLANATION
Thylakoid membranes contain pigments in light harvesting clusters that help in the light-dependent reactions, where the enzymes are also present.

QUESTION: Which combination of class and its description is correct?
A. Osteichthyes; a bony endoskeleton and gills covered by operculum
B. Reptilia; left aortic arch & internal fertilization
C. Nematoda; triploblastic & acoelomates
D. Cephalopods; dorsal nerve cord & bilateral symmetry
EXPLANATION
Osteichthyes is a class of fish with the following characteristics.

QUESTION: Which among the following defines GPI anchored proteins?
A. Integral proteins of the plasma membrane
B. Proteins that bind to ion-gated channels in the plasma membrane
C. Proteins which randomly bind to lipids of the plasma membrane
D. Peripheral proteins of plasma membrane
EXPLANATION
Glycosyl phosphatidylinositol (GPI)-anchored proteins are peripheral membrane proteins tethered to the cell through a lipid anchor. GPI-anchored proteins serve many functions in cellular physiology and cell signaling.

QUESTION: Phenotype represents which of the following?
A. Morphology
B. Physiology
C. Genetics
D. All of these
EXPLANATION
Phenotypes refers to the observable features of organisms which is the morphology, the structure of the organism.

QUESTION: Medulla, pons and cerebellum are found in which brain part?
A. Corpus callosum
B. Hindbrain
C. Forebrain
D. Midbrain
EXPLANATION
Hindbrain is composed of the medulla oblongata, the pons, and the cerebellum. The hindbrain coordinates functions that are fundamental to survival, including respiratory rhythm, motor activity, sleep, and wakefulness.

QUESTION: Which step causes activation of catalytic site of an enzyme?
A. Change in pH of the surroundings
B. Change in the charge of the active site
C. Change in temperature
D. Formation of Enzyme Substrate complex
EXPLANATION
When enzyme has substrate in its binding site, then the catalytic site is activated by the induced fit model. This also ensures that the product can be easily released.

QUESTION: The rigidity of leaves and younger parts of the plants is contributed by _____.
A. Microtubules
B. Mitochondria
C. Actin
D. Glyoxysomes
EXPLANATION
Glyoxysomes are specialized peroxisomes found in plants and mold, which help to convert stored lipids into carbohydrates so they can be used for plant growth.

QUESTION: Which is not a necessary condition for the Hardy-Weinberg equation to be true?
A. No natural selection
B. No net migration of individuals into or out of the population
C. Random mating
D. Small population
EXPLANATION
The population needs to be large for the Hardy-Weinberg equation to be true.

QUESTION: The period during which a girl sexually matures is called _____.
A. Menstrual cycle
B. Puberty
C. Childhood
D. Teens
EXPLANATION
Puberty is the stage of adolescence where hormones for secondary sex characters are released and a girl sexually matures.

QUESTION: In the rate equation R=k[A]a [B]b, a and b as exponents decide ________.
A. Direction of reaction
B. Extent of reaction
C. Order of reaction
D. Temperature of reaction
EXPLANATION
Option C “Order of Reaction “ is the correct answer.  Order of reaction may be defined as the number of molecules or reactants participating in rate determining step , in R=k[A]^a[B]^b , the exponent a is the order of reaction w.r.t specie A and b is the exponent of the order of reaction w.r.t specie B, the sum a+b is the overall order of reaction or simply order of reaction.

QUESTION: lodine has greater heat of sublimation then its family members due to presence of stronger _______.
A. H-bonding
B. London dispersion forces
C. Dipole-dipole forces
D. Chemical bonding
EXPLANATION
Option B “LONDON DISPERSION FORCES “ is the correct option.  London dispersion forces are forces of attraction between nonpolar molecules which become polar for an instant . These forces are often found in halogens (e.g,F2 and I2), Noble gasses(e.g, Ne and Ar) and other nonpolar molecules. The polarizability of molecules increases with increase in atomic and molecular size , thus IODINE is easily polarizable and due to having strong dispersion forces the heat of sublimation is greater i.e, +62.42 kj/mole.

QUESTION: The conversion of nitrogen to ammonia or nitrogenous compounds is called _______.
A. Nitrification
B. Nitrogen fixation
C. Denitrification
D. Assimilation
EXPLANATION
Option B “NITROGEN FIXATION ‘ is the right answer. The process of conversion of molecular nitrogen into ammonia or nitrogenous compounds is called NITROGEN FIXATION.

QUESTION: Which of the following is a weaker acid?
A. HCl
B. H2SO4
C. CH3COOH
D. H3PO4
EXPLANATION
Option C “CH3COOH” is the right option. Organic compounds are universally weaker acids . Thus, among strong mineral acids , Acetic acid (ch3cooh) is the weaker one.

QUESTION: Which of the following are products of the following reaction in the presence of sunlight? CH4 + Cl2 → _____
A. CHCl3
B. CCl4
C. CH2Cl2, CH3Cl
D. All of these
EXPLANATION
Option D is the right answer. This is a radical substitution reaction, also called halogenation (if chlorine is involved then chlorination , if bromine is involved then bromination) it is a photochemical reaction since it is taking place in the presence of sunlight. This reaction comprises of 3 steps:  1:- Initiation  2:-Propagation 3:-Termination

QUESTION: Nyholm & Gillespie explains the shapes of molecules for _________.
A. Transition elements
B. Non-transition elements
C. Only alkali metals
D. Alkaline earth metals
EXPLANATION
Option B NON TRANSITION ELEMENTS is the right option.  In 1957, Nylholm and Gillespie proposed VSEPR theory. The VSEPR theory does not shed any light on the compounds of transition metals, it deals with non-transition elements.

QUESTION: Downs Cell is used for the electrolysis of ________.
A. Aqueous NaCl
EXPLANATION
Option C “Fused NaCl” is the correct answer because Down Cells are commercially used to produce sodium metal which can be extracted electrolytically from Molten (fused) NaCl.

QUESTION: Structure of a crystal is changed due to ________.
A. Cooling
B. Heating
C. Impurity
D. None of these
EXPLANATION
Option C “IMPURITY” is the right option . If an impurity is present then the solid material changes its structure because new faces are produced in addition to the original one.

QUESTION: lonization energy depends on which of the following factors?
A. Size of atoms
B. Nuclear charge
C. Number of shells
D. All of these
EXPLANATION
Ionization energy depends on: *atomic size* *nuclear charge* *shielding/screening effect* *nature of orbital*

QUESTION: Lanthanides and actinides are also called as _________.
A. Rare earth elements
B. Outer transition elements
C. Non-typical elements
EXPLANATION
Lanthanides and actinides because of their geometrical properties are typically dispersed on earths surface and that is why they are called rare earth elements.

QUESTION: The value of Plancks constant h is _______.
A. 6.626x10-34 KJs
EXPLANATION
The value of planck constant is 6.626 x 10^-34Js.

QUESTION: Which of the following is not aromatic?
A. Anthracene
B. Naphthalene
C. Phenol
D. None of these
EXPLANATION
Phenols are molecules that have a hydroxyl group attached to the carbon atom of an aromatic ring.

QUESTION:  In thermodynamic terms boundary separates _________.
A. Surrounding from the environment
B. Reactants from contamination
C. System from surrounding
EXPLANATION
The real or imaginary surface separating the system from the surrounding is called the boundary.

QUESTION: Alkanes mostly give ___________.
A. Addition reactions
EXPLANATION
Under ordinary conditions, alkanes or paraffins are inert towards acids, alkalies, oxidizing and reducing agents. Under suitable conditions, alkanes undergo two types of reactions:  1:-substitution reaction 2:-thermal & catalytic reactions

QUESTION: The first ionization potential of alkaline earth metal is greater than alkali metals because _________.
A. They are more reactive
B. They have greater atomic radii
C. They have smaller atomic sizes
D. All of the above
EXPLANATION
In general, as we move from left to right in a period, the ionization energy of the elements increases due to successive increase in the nuclear charge and decrease in atomic size.

QUESTION: Calcium carbide on reaction with water gives __________.
A. Methane
B. Ethane
C. Propane
D. Acetylene
EXPLANATION
Carbide of alkaline earth metals are decomposed by water to form acetylene (C2H2). E.g: CaC2+ 2H2O —----- Ca(OH)2+ C2H2

QUESTION: Which one of the following is not the property of a system?
A. Enthalpy
B. Internal energy
C. Thermal energy
D. Temperature
EXPLANATION
Heat is an energy that is either entering or leaving a system by thermal means, it doesn’t thereby become a property of the system.

QUESTION: Which of the following is true about the kinetics of bimolecular elimination reactions?
A. 1st order reaction
EXPLANATION
According to kinetic evidence , the rate of reaction is directly proportional to substrate and base. It is second order kinetics and depends on the concentration of substrate and base.

QUESTION: The SI unit for work is _________.
A. Newtons
B. Joule
C. Newton/metre
D. All of these
EXPLANATION
The S.I unit of work is joule, work is also a form in which energy is transferred from one system to another. It is defined as the product of force and distance i.e. W = F x S

QUESTION: Near the completion of a chemical reaction, the average rate is __________.
A. Lower than the instantaneous rate
B. Higher than the instantaneous rate
C. Equal to the instantaneous rate
D. None of these options is correct
EXPLANATION
In the beginning, the instantaneous rate is higher than the average rate. At the end of the interval, the instantaneous rate is lower than the average rate.

QUESTION: Ice is an example of _________.
A. Polar molecular solid
EXPLANATION
Solids in which atoms and molecules are held together by intermolecular forces are called molecular solids. Hydrogen bonded molecular solids contain polar covalent bonds this ice is a familiar example of polar molecular solid.

QUESTION: There are just only a few stable compounds, formed by noble gases like _________.
A. XeF2
B. XeOF2
C. XeO3
D. All of these
EXPLANATION
There are just a few stable compounds formed by noble gasses like XeF2, XeF4, XeOF2, XeO3 etc.

QUESTION: Which of the following is an example of a good leaving group?
EXPLANATION
Compared to OH-, OR-, NH2- which are poor leaving groups , Cl- is a fairly good leaving group.

QUESTION: The rate of reaction _________.
A. Increases as reaction proceeds
EXPLANATION
As the reaction proceeds, the rate of reaction is slowing down with time because at the start, the rate of reaction is fast due to abundant reactants.

QUESTION: Which of the following acid is used a coagulant for latex in the rubber industry?
A. Acetic acid
B. Butyric acid
C. Propanoic acid
D. All of these
EXPLANATION
Acetic acid is used as a coagulant for latex in rubber industry.

QUESTION: In IUPAC nomenclature, ketones are named as _________.
A. Alkanol
B. Alkanal
C. Alkanone
D. Alkyl halides
EXPLANATION
The IUPAC name of ketones are derived from the names of alkanes having the same number of carbon atoms. The letter e in the name of alkanes is replaced with suffix -one making it alkanone.

QUESTION: Which of the following conditions must be possessed by a compound to have geometrical isomerism?
A. Double bond
B. Different groups attached to the carbon of double bond and a double bond
C. Terminal double bond
D. Same groups attached to the carbon atoms of the double bond
EXPLANATION
As each double bonded carbon atom is attached to two different groups, this compound shows geometrical isomerism.

QUESTION: In proteins, the H bonding is present between ___________.
A. C-H
B. N-H
C. O-H
D. Cl-H
EXPLANATION
Proteins are made of long chains of amino acids .The long chains of amino acids are coiled around each other into a spiral called helix, helix may either be right handed or left handed. In the right handed helix, the -NH groups of one spiral form hydrogen bonds with C=O of the other.

QUESTION: Due to less polarizability of fluorine, it boils at ________.
A. -188.1
EXPLANATION
Polarizability increases with increase in atomic and molecular size, among halogens fluorine has less polarizability so it boils at -188.1oC.

QUESTION: According to modern theory of chemical bonding, atoms forms bond to ________.
A. Increase energy
B. Decrease energy
C. Higher energy
D. None of these
EXPLANATION
According to modern theory of chemical bonding, (VBT,MOT) when atoms come together to form compounds, they attain lower energies then they possess as individual atoms thus becoming stable.

QUESTION: Metals are __________.
A. Reducing agents
EXPLANATION
All metals have low ionization energies and are relatively electropositive and so they lose electrons fairly easily, therefore, metals are good reducing agents.

QUESTION: Which type of forces are present between acetone and chloroform?
A. H-bonding
B. Dipole-dipole forces
C. London dispersion forces
D. Debye forces
EXPLANATION
Electronegative atoms responsible for hydrogen bonding include N, O, F and rarely Cl. According to the Punjab book (pg. 85), hydrogen bonds are present between molecules of chloroform (CHCl3) and acetone, as shown below.

QUESTION: In stoichiometry, we follow law of ________ while doing calculations.
A. Conservation of mass
B. Definite proportion
C. Both A and B
D. None of these
EXPLANATION
In stoichiometry , the law of conservation of mass and law of definite proportions are obeyed.

QUESTION: Vapor pressure is measured by calculating difference in liquid pressure and __________.
A. Mercury pressure
B. Glass pressure
C. Atmospheric pressure
D. Container pressure
EXPLANATION
Vapor pressure is measured by taking the difference in liquid pressure and atmospheric pressure. Note: Total pressure (also called liquid pressure) is the sum of the atmospheric pressure and vapor pressure.

QUESTION: Calculations regarding ionic character tells us that there is no bond when ionic character is _________.
A. 72%
B. 1%
C. 92%
D. 9%
EXPLANATION
Electronegativity is used to predict the nature of bonds or bond polarity. When the E.N in a bond is 1.8 r greater than the bond will be ionic , when E.N is below 0.5, the bond is normally classified as covalent bond. Ionic character refers to the percentage of difference between the electronegativity of two covalently bonded atoms. So, the bigger the difference between the electronegativity of two atoms, the more likely it is to be ionic.

QUESTION: 27 g of Al will react with how much mass of O2 to produce Al2O3?
A. 8g of oxygen
EXPLANATION
Option D is the right answer Solution   number of moles of Al = given mass/molar mass =27/27 = 1 mole The  balance equation for such reaction is 4Al + 3O2—------ 2Al2O3 Al : O2 4  :  3 1   : ¾ x1 = 0.75 0.75 moles of oxygen is used  Thus, mass of oxygen = 0.75 x 32  Answer = 24g

QUESTION: Protein component of enzyme is called ________.
A. Coenzyme
B. Cofactor
C. Apoenzyme
D. Prosthetic group
EXPLANATION
Apoenzyme is a protein part that binds to a non-protein cofactor to form an active conjugated enzyme known as the holoenzyme.

QUESTION: In a reaction having both alkyl halide and base, the base will attack on _________.
A. Electrophilic carbon
B. Nucleophilic carbon
C. Beta-hydrogen
D. None of these
EXPLANATION
This is the elimination reaction. In step 2 , which is the removal of β-hydrogen, base attacks β-hydrogen to form alkene.

QUESTION:  When a molten salt is electrolyzed the products are ________.
A. Complex
B. Predictable
EXPLANATION
When a molten salt is electrolyzed the products are predictable because when an aqueous solution of a salt is electrolyzed, hydrogen and oxygen appear at cathode and anode.

QUESTION: Nucleoprotein are ________ proteins which transfer heredity information from one generation to the other.
A. Transport protein
EXPLANATION
Nucleoproteins which are complexes of protein with nucleic acids serve as carriers of heredity from one generation to another and thus are referred to as genetic protein.

QUESTION: How many hydrogen atoms are attached to tertiary carbon in tertiary butyl alcohol?
A. 3
B. 2
C. 1
D. 0
EXPLANATION
A tertiary carbon atom is a carbon atom bound to three other carbon atoms. Here in tertiary-butyl alcohol , no hydrogen atom is attached to tertiary-carbon thus, option D is the right answer.

QUESTION:  Spectrometry is used when reactants and products absorb ___________.
A. Ultraviolet radiations
EXPLANATION
This method is applicable if a reactant or a product absorbs ultraviolet, visible or infrared radiations. The rate of reaction can be measured by measuring the amount of radiation absorbed.

QUESTION: How many unhybridized orbitals are there in ethyne molecule?
A. 1
B. 2
C. 3
D. 4
EXPLANATION
In the formation of ethyne molecules, both the carbon atoms undergo sp-hybridization having two unhybridized orbital i.e. 2py and 2px.

QUESTION: Grignard reagent is produced by the reaction of Alkyl halides with ________.
A. Ca in anhydrous ether
B. Mg in dry ether
C. Mg in hydrous ether
D. Ca in dry ether
EXPLANATION
When alkyl halide reacts with magnesium in the presence of dry ether grignards reagent is formed.

QUESTION: Electrolysis is a _________.
A. Spontaneous reaction
EXPLANATION
Electrolysis is a redox reaction brought by the application of direct current.

QUESTION: Glucose (C6H12O6) is the most important nutrient in a cell for generating chemical potential energy, what is the mass percent of carbon in 1.5g of sample?
A. 33%
B. 40%
C. 53.3%
D. 6.67%
EXPLANATION
Option B is the right answer, no matter how much the sample of glucose given , the mass percent of carbon will always be the same i.e, 40% Solution:- Mass percent= mass of the element/molar mass of the substance x 100 =72/180 x 100 = 40% ans

QUESTION: At equilibrium if the concentration of product is increased reaction will proceed to __________.
A. Forward direction
B. Backward direction
C. Remain undisturbed
D. None of these
EXPLANATION
If we increase the concentration of any one of the product C or D or both, then the reaction moves from right to to left in backward direction to increase the amount of reactant at time of equilibrium.

QUESTION:  For aldol condensation, carbonyl system must have __________.
A. Beta hydrogen
B. Beta carbon
C. Alpha carbon
D. Alpha hydrogen
EXPLANATION
Aldehyde and ketone possessing α-hydrogen atoms react with a cold dilute solution of alkali to form additional products known as ALDOOLS.

QUESTION: An orbital can accommodate at the most _________ electrons.
A. 2
B. 14
C. 1
D. 6
EXPLANATION
An orbital is an area where the electrons live. There can be two electrons in one orbital maximum.

QUESTION: The least value of Van der Waals constant is of ________.
A. H2
B. N2
C. CO2
D. Cl
EXPLANATION
The least value of van der waal cont is of H2 because of its small size and non polar character  i.e, 0.245 atm dm3/mol.

QUESTION: Organic compounds obtained from _____.
A. Living things
B. Non-living things
C. Fossils
D. Sea water
EXPLANATION
Organic compounds typically consist of groups of carbon atoms covalently bonded to hydrogen, usually oxygen, and often other elements as well. Created by living things, thus option A is the answer.

QUESTION: Which of the following family is linked with plant ashes?
A. Nitrogen family
B. Alkali metals
C. Rare earth metals
D. Oxygen family
EXPLANATION
Alkali came from the Arabic word which means the Ashes. Arabs used this term for these metals because they found that ashes of plants were chiefly composed of sodium and potassium.

QUESTION: The bond between the two atoms is non polar , if the E.N difference is ____.
A. 1.7
B. Zero
C. 1
D. 2
EXPLANATION
The difference in the electronegative values of the bonded atoms is an index to the polar nature of the covalent bond. When the difference is zero , the bond between the two atoms is nn polar.

QUESTION: The lattice energy of KBr is ____ KJ/mol.
A. -833
B. -665
C. -895
D. -728
EXPLANATION
The lattice energy of KBr is -665KJ/mol

QUESTION: Representing reaction in Voltaic cell symbol used for salt bridge is ____.
EXPLANATION
The salt bridge is represented by double line i.e, ‖

QUESTION: The efficiency of chemical reactions can be checked by calculating its _______ yield.
A. Percentage
B. Actual
C. Theoretical
D. Combination of all of these
EXPLANATION
The actual yield is obtained from the reaction. Theoretical yield is calculated from a balanced chemical equation. And the efficiency of a reaction is determined by percentage yield which is the ratio of actual yield to theoretical yield multiplied by 100.

QUESTION: In stationary waves:
A. Strain is maximum at antinodes
B. Strain is minimum at nodes
C. Strain is maximum at node
D. Amplitude is same at all points
EXPLANATION
In a stationary wave, the node is the point of minimum amplitude. Minimum amplitude means maximum strain, therefore strain is maximum at the nodes.

QUESTION: The distance between two consecutive crests of a travelling wave is 10 cm. If the speed of the wave is 50 cm/s, then its frequency would be:
A. 40 Hz
B. 1/5 Hz
C. 5 Hz
D. 500 Hz
EXPLANATION
The equation is given by: v = f \λ On rearranging the equation for frequency, we get, f = v/λ Putting values: f = (50 cm/s)/10 cm f = 5 Hz

QUESTION: The study of electric charges at rest in electric field is known as
A. electromagnetism
B. electrostatics
C. quantum physics
D. magnetism
EXPLANATION
B.Electrostatics is a combination of two words; Electro, referring to electricity (which is the flow of charges), and Statics, referring to the state of rest. Hence, it is the study of charges at rest. A. In Electromagnetism, we study the interaction of electric and magnetic fields. C. In Quantum Physics, we study the discrete packets of energy known as quanta. D. Magnetism is the study of magnetic fields and forces.

QUESTION: For step down transformer Ns ___ Np
A. equal to(=)
B. less than(<)
C. greater than(>)
D. not equal
EXPLANATION
A step down transformer produces a smaller output voltage than the input voltage provided to it. In order to achieve less output voltage, Vs, in the secondary coil, the number of turns on the secondary coil, Ns, should be less than the number of turns on the primary coil, Np.

QUESTION: The black body always __ radiations
A. emit
B. absorb
C. both a and b
D. reflects
EXPLANATION
Black Bodies are ideal entities that have the ability to absorb all forms of radiation that they come across. They can then emit those radiations in a spectrum, Eg; our sun emits radiation in the yellow or green portion of the spectrum.

QUESTION: The rate of change of angular velocity is called _____.
A. Angular displacement
B. Angular acceleration
C. Angular velocity
D. Acceleration
EXPLANATION
B. Angular acceleration is the rotational analogue of linear acceleration. The rate of change of linear velocity is known as linear acceleration, and the rate of change of angular velocity is known as angular acceleration. A. Angular displacement is the angle formed when a body revolves in a circle about an axis. C. Angular velocity is the rate of change of angular displacement in rotational motion. D. Acceleration is the rate of change of velocity (linear).

QUESTION: A 250V bulb passes a current of 0.3A. Calculate the power in the lamp.
A. 50W
B. 75W
C. 100W
D. 90W
EXPLANATION
The equation for power is given by, P = V I Putting values, P = 250 V × 0.3 A P = 75 W

QUESTION: Work is a _____.
A. Vector quantity
B. Scalar quantity
C. Sometime scalar some time vector
D. None of these
EXPLANATION
Work is given as; W = F × d Work is the product of Force, and displacement, both of which are vectors. The product of two vectors is a scalar quantity.

QUESTION: Magnetic field along the axis of solenoid with n turns per unit length carrying current I is given by _____.
A. B = μonl
B. B = μoN/L
C. B = μoIN
D. B = μoINL
EXPLANATION
B = μonl is the formula for magnetic field across a solenoid.

QUESTION: A succession of events which bring the system back to its initial condition is called _____.
A. Oscillation
B. Vibration
C. Cycle
D. Circle
EXPLANATION
A cycle is a successive array of small thermodynamic processes that help the system return to its initial state.

QUESTION: The negative sign in F = -k.x indicates that _____.
A. F is directed opposite to x
B. F is directed along x
C. F is always equal to x
D. none of these
EXPLANATION
The negative sign in the equation indicates the opposite direction of the force, as the cos of 180° is -1.

QUESTION: What will be the product after alpha decay of U-238?
A. Th-234
B. Po-234
C. Rn-234
D. None of these
EXPLANATION
The decay equation of Uranium-238 is as follows; U-238→He-4+Th-234

QUESTION: Which is not radioactive?
A. Ozone
B. Hydrogen
C. Sodium
D. All of these
EXPLANATION
D. Radioactive elements have unstable nuclei that lose energy in the form of radiation. And none of them are radioactive A. Ozone is given by the formula O₃, and is a stable molecule. B. Atomic hydrogen is neutral, thus stable. However the isotope of hydrogen, tritium shows spontaneous decay. C. Sodium belongs to the 3rd period and 1st group of the periodic table. It is a stable metal with a Z number of 11. The only element in group 1 that shows decay is Francium.

QUESTION: Half wave rectifier uses _____.
A. One diode
B. Two diodes
C. Three diodes
D. Four diodes
EXPLANATION
Half wave rectifier uses one diode to limit the flow of current in one direction only. This will allow only one half of the AC wave to pass through it.

QUESTION: Under which conditions does a real gas approximate to an ideal gas?
A. Pressure = high density = high
B. Pressure = low density = high
C. Pressure = high density = low
D. Pressure= low density= low
EXPLANATION
Under extremely low pressure, the gas particles will have less intermolecular forces, as a result of which, they will be scattered more freely, thus behaving as ideal gases.

QUESTION: If a car moves with a uniform speed of 2 ms^-1 in a circle of radius 0.4, its angular speed is _____.
A. 4 rads^-1
B. 5 rads^-1
C. 1.6 rads^-1
D. 2.8 rads^-1
EXPLANATION
The given data is; Speed, v = 2m/s  Radius, r = 0.4m Angular speed, w, is required. The relation between linear and angular velocities is given by; v = r w Or w = v/r w = 2ms^-1 / 0.4 m w = 5 rad/s

QUESTION: If the length of a potentiometer wire is doubled, the accuracy in determining the null point _____.
A. Is increased
B. Is decreased
C. Remains constant
D. May increase or decrease
EXPLANATION
The accuracy of a potentiometer is inversely dependent upon the potential gradient. A smaller potential gradient means a higher accuracy. As the potential gradient is inversely dependent upon the length of the potentiometer wire, we can decrease the potential gradient by increasing the wire. This in turn, increases the accuracy of the potentiometer.

QUESTION: If the velocity varies linearly with time then acceleration is called _____.
A. Non-uniform
B. Discrete
C. Instantaneous
D. Uniform
EXPLANATION
If a bodys speed increases equally in equal intervals of time, the time rate of change of speed is known as uniform acceleration.

QUESTION: You have three capacitors, each of 2 μC. In which of the following combinations of the three capacitors, the resultant capacitance is 6μC?
A. All three capacitors in series
B. Two capacitors are in series, one in parallel
C. Two capacitors are in parallel, one in series
D. All three capacitors in parallel
EXPLANATION
For capacitors in parallel, the total capacitance is calculated through; Ct = C1 + C2 + C3 Ct = 6μC This gives the highest net capacitance among the given options.  A. For capacitors in series, the total capacitance is calculated through; Ct = 1/C1 + 1/C2 + 1/C3 Ct = 1/2μC + 1/2μC + 1/2μC Ct = 9/6μC = 1.5μC The net capacitance is lower than the individual capacitances. B. For two capacitances in series; Ct = 1/C1 + 1/C2 —[1] For one capacitor in parallel; Ct = C3 —[2] Adding [1] and [2], Ct = 1/C1 + 1/C2 + C3 Ct = 1/2μC + 1/2μC + 2μC Ct= 3μC C. For two capacitors in parallel; Ct = C1 + C2 —[1] For one capacitor in series; Ct = 1/C3 —[2] Adding [1] and [2], Ct = C1 + C2 + 1/C3 Ct = 2μC + 2μC + 1/2μC Ct = 4μC + 1/2μC Ct = 9/2μC Ct = 4.5μC

QUESTION: Light of wavelength 450 nm is incident on a diffraction grating on which 5000 lines/cm have been ruled. How many orders of spectra can be observed on either side of the direct beam?
A. 1
B. 2
C. 3
D. 4
EXPLANATION
Wavelength of light, λ = 450 nm = 4.5×10^-5cm Number of lines per cm, N = 5000 Required: The orders of spectra that can be observed, n=? Solution: n = 1/λN n=1/4.5× 10^-5 cm × 5000 n = 4.44 ~ 4

QUESTION: One kcal is equal to _____.
A. 4.18 J
B. 4180 J
C. 2.09 J
D. 2090 J
EXPLANATION
One Kcal = 4.18 KJ or 4180 J

QUESTION: We can calculate velocity of an object from displacement-time graph by _____.
A. Calculating area under the graph
B. Finding gradient of displacement-time graph
C. Calculating area above the graph
D. Finding the length of the graph
EXPLANATION
The slope or gradient of a displacement-time graph gives us the velocity.  We know that; Slope = y/x For a displacement-time graph, the independent x-axis is time, t, while the dependent y-axis is displacement, d; Slope = d/t  d/t = v

QUESTION: If a charged particle moves through a magnetic field perpendicular to it, _____.
A. Both momentum and energy of particle change
B. Momentum as well as energy are constant
C. Energy is constant but momentum changes
D. Momentum is constant but energy changes
EXPLANATION
If a charged particle moves through a magnetic field perpendicular to it, it acquires circular motion. During circular motion, the velocity of the body changes at each point. As momentum depends upon the velocity, by the equation, P = mv, the momentum also changes with the velocity. Only the direction of the velocity is changing, whereas its magnitude remains constant. From the equation of Kinetic energy, K.E = ½ mv², it is evident that the square of the velocity means no change in magnitude.

QUESTION: When a man walks on a surface horizontally with constant velocity, work done by _____.
A. Friction is zero
B. Contact force is zero
C. Gravity is zero
D. All of these
EXPLANATION
Since mg and N are perpendicular to velocity   v and s, work done by these force is zero. Since no relative sliding occurs during walking, static friction comes into play. Hence the point of application of static frictional force does not move. Therefore no work is done by frictional force. The man has to lose his bodys (internal) energy E, hence performs work because W=ΔE

QUESTION: The direction of induced current is always so as to oppose the change which causes the current is _____.
A. Faradays Law
B. Lenzs Law
C. Ohms Law
D. Kirchoffs Law
EXPLANATION
Lenz law states that, The direction of induced current is always so as to oppose the change which causes the current. ε = -N dΦB/dt Where, ε = Induced emf  dΦB = change in magnetic flux  N = No of turns in coil

QUESTION: An object is moving at constant speed, which of the following is always true?
A. Distance is greater than displacement
B. Distance is lesser than displacement
C. Distance is equal to displacement
D. We cannot answer
EXPLANATION
Distance can either be greater than displacement, or equal to it. However, even if both distance and displacement are not equal, distance is always going to be greater than displacement, therefore this situation is the one that prevails.

QUESTION: A transverse wave on a string has an amplitude A. A tiny spot on the string is colored red. As 1.5 cycle of the wave passes by, what is the total distance traveled by the red spot?
A. A
B. 2A
C. 4A
D. 6A
EXPLANATION
The particles in a transverse wave oscillate periodically in a direction perpendicular to the propagation of the wave. This means that the string is undergoing SHM. For simple harmonic motion, one complete cycle is equal to 4 times the amplitude. One cycle goes as follows; Upward movement, Downward movement, then again Upward in the opposite direction, and finally back to its mean position, completing a total distance of 4A.  If, 1 cycle = 4A Then, 1.5 cycle = x x = 1.4 × 4A x = 56/10 A x = 5.6A ~ 6A

QUESTION: Reciprocal of resistivity is called _____.
A. Resistance
B. Inductance
C. Conductivity
D. Flexibility
EXPLANATION
Conductivity is inversely proportional to resistivity, such that σ = 1/ρ = L/RA

QUESTION: The sensitivity of a potentiometer can be increased by _____.
A. Increasing the e.m.f. of the primary cell
B. Increasing the potential gradient
C. Increasing the length of the potentiometer wire
D. Decreasing the length of the potentiometer wire
EXPLANATION
A potentiometers accuracy (sensitivity) is inversely dependent upon the potential gradient. The smaller the gradient, the higher the sensitivity. The potential gradient can be reduced by increasing the length of the potentiometer wire. Thus a longer potentiometer wire, means a more sensitive potentiometer.

QUESTION: If the velocity of a charged particle and magnetic field are at a fixed angle (not 90⁰), then the path will be _____.
A. Circular
B. A straight line
C. Spherical
D. Helical
EXPLANATION
The force in a magnetic field is given by, F=qVBsinθ, where if θ is smaller than 90° and greater than 0°, it moves in a helical path, while sin90° gives the maximum circular motion.

QUESTION: You have two identical capacitors. They can be connected in series or in parallel. If you want the smallest equivalent capacitance for the combination, how should you connect them?
A. In parallel
B. In series
C. Either way because both combinations have the same capacitance
D. We can not determine, because presence of resistance in the circuit determines capacitance
EXPLANATION
In series, the net capacitance of the capacitors is less than the individual capacitances.   Ct = 1/C1 + 1/C2 + 1/C3 Thus any values for C1, C2, and C3 will become less than the original as they are each divided by 1.

QUESTION: Which is the following is not a unit of angular displacement?
A. Degree
B. Revolution
C. Meters
D. Radian
EXPLANATION
Radians, degrees, and revolutions are the units of angular displacement. Angular displacement is defined as the angle through which an object moves on a circular path. It is the angle between the initial and final positions measured in radians.

QUESTION: Half wave rectifier passes only _____.
A. Lower half cycle
B. Upper half cycle
C. Both cycles
D. None of them
EXPLANATION
The single-phase half-wave rectifier configuration above passes the positive half of the AC supply waveform with the negative half being eliminated.

QUESTION: If the number of flux passing through a coil per unit time is doubled then the motion emf _____.
A. Halves
B. Triples
C. Doubles
D. Remains unchanged
EXPLANATION
Faradays law of induction states that the EMF induced by a change in magnetic flux is EMF=−NΔΦΔt EMF = − N Δ Φ Δ t , when flux changes by Δ in a time Δt. So doubling the flux, doubles the motion emf.

QUESTION: An ideal reversible heat engine is 1 efficient only if _____.
A. Hot reservoir is at 0K
B. Hot reservoir is at 0C
C. Cold reservoir is at 0C
D. Cold reservoir is at 0K
EXPLANATION
Efficiency of carnot engine= (1-T2/T1)*100 T2=cold reservoir temp. T1=hot reservoir temp. If = (1-0/T2)*100 =(1-0)*100 =1*100 Efficiency = 100%

QUESTION: Whenever a transverse wave travelling in a denser medium is reflected from the boundary of the rarer medium, _____.
A. An incident crest on reflection disappears
B. An incident trough on reflection becomes double
C. An incident crest on reflection becomes a trough
D. An incident crest on reflection remains crest
EXPLANATION
If a crest of a transverse wave, in a denser medium, is incident at a point of a rarer medium, as the particles of rarer medium are free to vibrate, it will displace the particle at the point of incidence in the upward direction and after reflection from the rarer medium, a crest returns as a crest or a trough returns as a trough.

QUESTION: Mass and energy are related to each other by _____.
A. Newtons law
B. Einstein law
C. Coulomb law
D. All of these
EXPLANATION
Energy and Mass Are Relative The equation E = mc^2 states that the amount of energy possessed by an object is equal to its mass multiplied by the square of the speed of light. This is the Einsteins Law.

QUESTION: The spectrum of white light lies _____.
A. Above 300 nm
B. Below 300 nm
C. In between UV to IR
D. None of these
EXPLANATION
The spectrum of white light consists of six basic colours arranged in a specific order: red, orange, yellow, green, blue and violet. i.e between Infrared and Ultraviolet.

QUESTION: A travelling transverse wave has amplitude a and wavelength λ. What is the minimum distance between a crest and a trough in the direction of propagation of wave?
A. 2a
B. a/2
C. 2λ
D. λ/2
EXPLANATION
The distance between a crest and a consecutive trough is half of the wavelength. The highest surface part of a wave is called the crest, and the lowest part is the trough

QUESTION: Which of the following is not an assumption of the kinetic model of an ideal gas?
A. Collisions between molecules and walls of container are elastic
B. The duration of collision between molecules is very short
C. All particles of gas has same speed
D. All particles of gas have same mass
EXPLANATION
Postulates of Kinetic Theory of Gases are as follows 1.The molecules in a gas are small and very far apart. Most of the volume which a gas occupies is empty space. Gas molecules are in constant random motion. Just as many molecules are moving in one direction as in any other. Molecules can collide with each other and with the walls of the container. Collisions with the walls account for the pressure of the gas. When collisions occur, the molecules lose no kinetic energy; that is, the collisions are said to be perfectly elastic. The total kinetic energy of all the molecules remains constant unless there is some outside interference with the The molecules exert no attractive or repulsive forces on one another except during the process of collision. Between collisions, they move in straight lines.

QUESTION: The bridge rectifier is preferred to an ordinary two diode full wave rectifier because _____.
A. It needs much smaller transformer for the same output
B. No center tap required
C. Less PIV rating per diode
D. All of the above
EXPLANATION
For a bridge rectifier, the Peak inverse voltage is less per diode and the rectifier uses a smaller transformer that does not require a tap. The ordinary two wave full rectifier, in comparison, produces the same output but with larger transformers and have higher PIV values per diode.

QUESTION: A radioactive element emits 200 particles per second. After three hours 25 particles per second are emitted. The half life period of element will be _____.
A. 80 minutes
B. 70 minutes
C. 60 minutes
D. 50 minutes
EXPLANATION
.

QUESTION: Which light photon has the least momentum?
A. Red
B. Green
C. Yellow
D. Blue
EXPLANATION
The momentum of a photon depends upon its wavelength. Red light has the shortest wavelength in the visible spectrum therefore its momentum is the least among the options.

QUESTION: The energy input to an engine is 60 J, and the work it performs is 15 J. What fraction of the energy input is expelled to the cold reservoir?
A. 0.25
B. 75%
C. 1
D. Impossible to determine
EXPLANATION
.

QUESTION: A 220 V main supply is connected to a resistance of 100 k ohms. The effective current is _____.
A. 2.2mA
B. 2.2/v2 mA
C. 2.2 x v2 mA
D. None of the above
EXPLANATION
We know that, V = IR I = VR I = 220V/100k.ohm I = 2.2 mA

QUESTION: The photoelectric effect is not possible with _____ photons.
A. X-rays
B. Beta rays
C. Gamma rays
D. All of these options are correct
EXPLANATION
It will depend on the photoelectric material in question, but generally, the wavelength of the light will have to be short enough so that the photons can interact with the photoelectric material, and long enough that they won’t pass through the photoelectric material. To release electrons from typical metals requires photons with at least a few electron-volts. This corresponds to short-wavelength visible or ultraviolet light. The above-given options have very short wavelength which is not long enough to stay within the metals whereas it bypasses the metal creating no photoelectric effect.

QUESTION:  The charge on gamma rays is _____.
A. 1+
B. 1-
C. 0
D. None of these
EXPLANATION
The high penetrating power and long range of gamma rays are both a product of the lack of a charge on them. There is no charge on gamma rays because of their net neutrality.

QUESTION: The half-life of radium is about 1600 years. Of 100 g of radium existing now, 25 g will remain unchanged after _____.
A. 2400 years
B. 3200 years
C. 6400 years
D. 4800 years
EXPLANATION
Two half lives later, 100g of gamma rays will be reduced to 25g.  100/2² = 25  The half life of Radium = 1600 years Time taken = 2×1600                     = 3200 years

QUESTION: A stationary wave is formed in a pipe which is open at one end. If length of pipe is L, then what is the maximum possible wavelength of the wave?
A. L2 L
B. 2 L
C. 3 L
D. 4 L
EXPLANATION
In a tube with one open end and one closed end f1 = v/4L, λ = v/f = 4L

QUESTION: What is the power of a bulb if it is operated at 220V and the current in the circuit is 1.5A?
A. 330W
B. 430W
C. 530W
D. 500W
EXPLANATION
Power = current x voltage           = 1.5 x 220           P=330 watt

QUESTION: In a rectifier, the larger the value of the shunt capacitor filter, _____.
A. Larger the peak-to-peak value of the ripple voltage
B. Larger the peak current in the rectifying diode
C. Longer the time the current pulse flows through the diode
D. Smaller the voltage across the load
EXPLANATION
C= ΔQ/ΔV = I x t/ΔV If C increases, t increases for constant input power and voltage. Hence the time t for which current flows through the diode increases.

QUESTION: A stationary wave is formed in a pipe which is open at both ends. If length of pipe is 10 cm, then what is the maximum possible wavelength of the wave?
A. 20 cm
B. 5 cm
C. 10 cm
D. 30 cm
EXPLANATION
Let the wavelength of the wave be λ and the length of the open pipe be l. So, length of pipe = λ/4 + λ/4 ⇒ l = λ/2; As the diagram shows. ⇒ λ = 2l Since the length of the pipe is 10 cm; therefore, the maximum wavelength of the pipe is; 2 × 10 = 20cm.

QUESTION: If the potential difference across the two plates of a parallel plate capacitor is doubled, then energy stored in the capacitor would _____.
A. Remain the same
B. Be two times
C. Be four times
D. Be three times
EXPLANATION
.

QUESTION: P-V diagram of a diatomic gas is a straight line passing through origin. What is the molar heat capacity of the gas in the process?
A. R
B. 1.5R
C. 3R
D. 4R/3
EXPLANATION
.

QUESTION: When a stone is thrown horizontally with 2 m/s from a building of height 5 m then just before hitting ground its acceleration is _____.
A. 12 m/s^2
B. 13 m/s^2
C. 9.8 m/s^2
D. 7.6 m/s^2
EXPLANATION
When the stone is falling down, it falls in the category of projectile motion and in projectile motion we consider a=g=9.8 m/s^2.

QUESTION: The angular acceleration is equal to linear acceleration when _____.
A. r=maximum
B. r=0
C. r=1
D. None of these
EXPLANATION
Linear acceleration (a) and angular acceleration (α) are related by the equation:  a = α x r Hence if r = 1, a= α.

QUESTION: Statements and Actions: Statement: as stated in the recent census report the female to male ratio is alarmingly low.  I. The government should conduct another census to verify the results.  II. The government should immediately issue orders to all the departments to encourage people to improve the ratio.
A. Both of them follows
B. None of them follows
C. Only I follows
D. Only II follows
EXPLANATION
A census is always conducted with the utmost precision, leaving chances of only negligible differences. So, I does not follow. Further, the ratio can be improved by creating awareness among the masses and abolishing female foeticide. Thus, only course II follows.

QUESTION: Dependent causes/ Independent causes: Statement: There is an unprecedented increase in the number of young unemployed in comparison to the previous year. A large number of candidates submitted applications against an advertisement for the post of manager issued by a bank.
A. Statement I is the cause and statement II is its effects
B. Statement II is the cause and statement I is its effect
C. Both the statements I and II are independent causes
D. Both the statements I and II are effects of independent causes
EXPLANATION
An increase in the number of unemployed youth is bound to draw in huge crowds for a single vacancy.

QUESTION: Verbal Classification: Find the odd one out: 24, 36, 52, 72, 96
A. 72
B. 52
C. 36
D. Both A and B
EXPLANATION
all but 52 are multiples of 12

QUESTION: Verbal Classification: At what time between 4 and 5 oclock will the hands of a watch point in opposite directions?
A. {54 + 6/11) past 4
B. {54 + 8/11) past 4
C. {53 + 7 /11) past
D. Both A and B
EXPLANATION
At 4 o’clock the hands of watches are 20 minutes spaces apart. To be in opposite directions, they must be in 30 minutes spaces apart. So, the minute hand will have to gain 50-minute spaces. 55-minute spaces are gained in 60 minutes. 50 minute spaces are gained in = (60 ÷ 55) × 50 = 54 (6/11) So, required time = 54 (6/11) minutes past 4 Hence, the correct answer is (54 + 6/11)minutes past 4.

QUESTION: Statement and Argument: Statement: Should children be prevented completely from watching television?  Arguments  (I) No. We get vital information regarding education through television.  (II) Yes. It hampers the study of children.  (Ill) Yes. Young children are misguided by certain programs featuring violence.
A. Only I, II, and Ill are strong
B. Only I is strong
C. Only I and II are strong
D. Only I and III are strong
EXPLANATION
Clearly, television offers various educational programs which are of great practical value to the students. So, it serves as a means (but it is not the only means) to educate the masses. Thus, I holds strong.  Besides, the demerits of watching television, mentioned in II and III, may be done away with by allowing children to watch selected programs on television, according to a set schedule. So, neither II nor III hold strong.

QUESTION: Complete the series: CMM, EOO, GQQ, __ , KUU
A. GRR
B. GSS
C. ISS
D. ITT
EXPLANATION
The first letters are in alphabetical order with a letter skipped in between C d E f G h.. so the first letter will be I. The second and third letters are repeated; they are also in order with a skipped letter: M n O p Q r.. so the next two letters will be S giving us the answer ISS.

QUESTION: Statement and Argument: Statements: Should admission to the professional degrees in Pakistan be given only on merit without any concession to any particular group of students?  Arguments: (I) Yes. This will improve the quality of the professional institutes and degrees as they will be able to complete the degree successfully.  (II) No. This will keep a large number of socially and economically backward students out of the reach of professional institutes and degrees.
A. If argument I is strong.
B. If only argument II is strong
C. If both I and II are strong.
D. If neither I nor II is strong
EXPLANATION
Our country seeks to support educationally and economically backward classes for their overall growth and development.

QUESTION: Complete the series A25, B625, C15625, __
A. D390625
B. D364748
C. D390524
D. D390525
EXPLANATION
each number is multiplied by 25. 15625x25 is 390,625 hence The answer is D 390,625.

QUESTION: Directions to solve: In each of the following questions a statement is given, followed by two conclusions. Give answer:  Statement: Please do not wait for me, I may be late, start taking lunch as soon as the guests arrive. - A message from a Director of a Company to his office managers.  Assumptions: I. Keeping guests waiting is not desirable. II. Lunch may not be ready in time.
A. Only assumption I is implicit
B. Only assumption II is implicit
C. Either I or II is implicit
D. Both A and B
EXPLANATION
Clearly, the Director instructs his managers not to keep the guests waiting because of him and to proceed with lunch soon after their arrival. This implies that lunch would be ready in time. So, only I is implicit.

QUESTION: Logical games: If - means+, + means -, * means ÷ and ÷ means * then which of the following will be the correct equation?
A. 30 + 5 + 14 - 10 * 15 = 122
B. 10 + 5 - 14 + 10 * 15 = 158
C. 30 - 5 + 14 + 10 * 15 = 162
D. 30 * 5 - 4 + 10 + 15 = 31
EXPLANATION
According to this only the last equation 30*5-4+10+15 is giving us the correct answer. 30 ÷ 5 +4-10-15 gives us 31.