PMC Paid Practice Tests Series 2021 With Explanation - Test 16

[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: Demonstrate correct use of writing conventions of spelling, capitalization and punctuation to clarify meaning. Choose the correct sentence.
A. Dr Hussain works at city hospital in gulberg.
B. Dr Hussain works at City Hospital in Gulberg?
C. Dr Hussain works at City Hospital in Gulberg.
D. Dr Hussain works at city hospital in Gulberg.
EXPLANATION
The above sentence is a statement, therefore, will end with a full stop and not any other type of punctuation like a question mark or so. “City Hospital” is the name of a specific hospital and “Gulberg” is the name of a place therefore they are both proper nouns and must be capitalized.

QUESTION: Demonstrate correct use of articles and prepositions.  I bought _______ new TV set yesterday.
A. a
B. an
C. the
D. no article
EXPLANATION
A/an and the are articles. They are a type of determiner and they go before a noun. Use “a” before words that start with a consonant sound and “an” before words that start with a vowel sound.

QUESTION: I ___ English since my childhood.
A. study
B. am studying
C. have been studying
D. studied
EXPLANATION
have been suggests an action that started in the past, but continues in the present. When we are talking about the present: If the subject of a sentence is I – You – We – They or a plural noun (cars, birds, children) we use have been.

QUESTION: Demonstrate control of tenses and sentence structure.  Have you ___ the examination?
A. take
B. took
C. taken
D. taking
EXPLANATION
the past participle (taken) is used to show a completed action before another, both occurring in the past.

QUESTION: Comprehend key vocabulary.  We are planning to get a big, ____ table for our dining-room
A. rough
B. empty
C. deep
D. round
EXPLANATION
Usually people have large, round tables to grandly dine on. Also round makes a better, more pleasant description of a table.

QUESTION: Comprehend key vocabulary.  Rainfall in the desert is not only extremely low, but also extremely ____
A. intense
B. erratic
C. meagre
D. undesirable
EXPLANATION
Erratic means not regular in pattern or movement; unpredictable. Therefore it makes sense to describe rain as erratic, especially in the desert.

QUESTION: Demonstrate control of tenses and sentence structure.  Choose the future indefinite tense form of the given sentence. The parcel has been delivered.
A. The parcel had been delivered.
B. The parcel will be delivered.
C. The parcel was delivered.
D. The parcel would have been delivered.
EXPLANATION
Will is used to indicate future tense and the future form of been is will be.

QUESTION: Demonstrate control of tenses and sentence structure.  Identify the tense used in the given sentence. Everyone shall be reaching by tomorrow.
A. Present
B. Past
C. Future
D. none
EXPLANATION
Shall refers to the future in all instances.

QUESTION: Choose the correct sentence.
A. Today was her sisters birthday so she took her out for dinner.
B. Today was her sisters birthday, so she took her out for dinner.
C. Today was her sisters birthday so she took her out for dinner.
D. Today was her Sisters birthday, so she took her out for dinner.
EXPLANATION
It is important to use commas to separate independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, for, or, nor, so, yet. An apostrophe must also be present to indicate possession (bday of sister)

QUESTION: Demonstrate correct use of writing conventions of spelling, capitalization, and punctuation to clarify meaning. Choose the correct spelling of the word
A. probaly
B. probably
C. probebly
D. probly
EXPLANATION
Probably means almost certainly; as far as one knows or can tell.

QUESTION: Demonstrate correct use of the subject-verb agreement. My friends _________ too much.
A. worries
B. worry
C. worried
D. worrying
EXPLANATION
Since the noun is plural (friends), the verb will singular: worry.

QUESTION: Comprehend key vocabulary.   nemesis
A. associate
B. antagonist
C. soul-mate
D. ally
EXPLANATION
Nemesis means an arch-enemy, thus antagonist is a suitable synonym.

QUESTION: Demonstrate correct use of articles and preposition. This is ___ good company to work with.
A. a
B. an
C. the
D. no article
EXPLANATION
A/an and the are articles. They are a type of determiner and they go before a noun. Use “a” before words that start with a consonant sound and “an” before words that start with a vowel sound.

QUESTION: Demonstrate correct use of articles and prepositions. I work as ______ only English teacher at this school.
A. a
B. an
C. the
D. no article
EXPLANATION
The is used to provide emphasis and specificity.

QUESTION: Choose the correct sentence.
A. Help help! Me Im drowning.
B. Help! Help me! Im drowning!
C. Help, help me. Im drowning.
D. Help help me! Im drowning!
EXPLANATION
Exclamation marks are used at the end of statements when a strong emotion is being expressed (good and bad – surprise, excitement or delight, but also anger, fear, or shock), and tell a reader to add emphasis to a sentence. They might also suggest that a speaker is shouting.

QUESTION: Choose the correct spelling of the word.
A. Shekspeare
B. Shakspare
C. Shakespare
D. Shakespeare
EXPLANATION
William Shakespeare was an English playwright, poet, and actor, widely regarded as the greatest writer in the English language and the worlds greatest dramatist.

QUESTION: Demonstrate correct use of writing conventions of spelling, capitalization, and punctuation to clarify meaning.  Choose the correct sentence.
A. Mrs Sajjad: who was sitting behind the desk, gave me a big smile.
B. Mrs Sajjad who was sitting behind the desk gave me a big smile.
EXPLANATION
Commas are used to separate independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, for, or, nor, so, yet. A question mark will not be used as this is not a question but a statement, so a full stop will be the appropriate choice.

QUESTION: Demonstrate control of tenses and sentence structure.  We _______ (eat) the popcorn and _______ (drink) the orange juice.
A. eat, drink
B. ate, drink
C. eat, drank
D. ate, drank
EXPLANATION
The entire sentence must be in the same tense (past).

QUESTION: Demonstrate correct use of the subject-verb agreement. None ____none under the sun.
A. is
B. are
C. were
D. was
EXPLANATION
When deciding whether to use is or are, look at whether the noun is plural or singular. If the noun is singular, use is.

QUESTION: Demonstrate correct use of articles and prepositions. There is _______ institution for _____ blind in this city.
A.  a ... an
B. a ... the
C. an … a
D. an … the
EXPLANATION
A/an and the are articles. They are a type of determiner and they go before a noun. Use “a” before words that start with a consonant sound and “an” before words that start with a vowel sound. The is used to indicate that the institution is specifically for the blind.

QUESTION: The fate of each blastomere is foretold. What will that cleavage be?
A. Spiral and indeterminate
B. Radial and indeterminate
C. Radial and determinate
D. Spiral and determinate
EXPLANATION
Explanation: Cleavage in protostomes is spiral and determinate. Spiral means that the planes of cell division are diagonal to the vertical axis of the embryo. Determinate means that the fate of each embryonic cell is fixed very early.  In deuterostomes, the cleavage is radial and indeterminate. Radial means the planes are either parallel or perpendicular to the vertical axis of the embryo. Indeterminate means that each cell produced by early cell divisions can develop into a complete embryo (its fate is not fixed).

QUESTION: The inherited instructions an organism carries within its genome is its?
A. phenotype
B. clone
C. recombination
D. genotype
EXPLANATION
The genotype is the genetic makeup, or set of alleles, of an organism. Phenotype is the observable physical and physiological traits of an organism, which are determined by its genetic makeup. Clones refer to genetically identical individuals or cells. Recombination is the process by which pieces of DNA are broken and recombined to produce new combinations of alleles.

QUESTION: Some bacteria ranging occasionally a size of 500 µm in length are which of the following?
A. Escherichia coli
B. Mycoplasma
C. Epulopiscium
D. Spirochetes
EXPLANATION
Some spirochetes occasionally reach 500 micrometres in length.

QUESTION: The chief cells at the base of the gastric glands secrete the zymogen which is called?
A. trypsinogen
B. pepsin
C. trypsin
D. pepsinogen
EXPLANATION
Chief cells within the gastric glands secrete inactive pepsinogen. Pepsinogen is packaged in zymogen granules which are released by exocytosis when the cells are stimulated to secrete pepsinogen.

QUESTION: Which two reactions occur during photophosphorylation.
A. ATP is hydrolysed and NADP is reduced.
B. ATP is hydrolysed and NADPH is oxidized.
C. ATP is synthesized and NADP is reduced.
D. ATP is synthesized and NADPH is oxidized.
EXPLANATION
During photophosphorylation, ATP is synthesised via chemiosmosis while NADP is reduced to NADPH.

QUESTION: Choose the organ that filters the lymph.
A. heart
B. liver
C. spleen
D. pancreas
EXPLANATION
Just as the lymph nodes filter lymph, the spleen filters blood, exposing it to macrophages and lymphocytes that destroy foreign particles and aged red blood cells.

QUESTION: Paramyxoviruses cause which disease?
A. influenza
B. smallpox
C. mumps and measles
D. AIDS
EXPLANATION
Mumps and measles are caused by paramyxoviruses.

QUESTION: Secondary cell wall of sclerenchyma cells is impregnated with?
A. cellulose
B. lignin
C. murein
D. pectin
EXPLANATION
Sclerenchyma cells have thick secondary cell walls usually impregnated with lignin, an organic substance that makes the walls tough and hard.

QUESTION: In sexual reproduction, plants have diplohaplontic life cycle with alternating?
A. Haploid sporophyte and diploid gametophyte generations.
B. Diploid sporophyte and diploid gametophyte generations.
C. Haploid sporophyte and haploid gametophyte generations.
EXPLANATION
The gametophyte is the haploid generation which reproduces sexually by forming haploid gametes. The sporophyte is the diploid generation which reproduces asexually by forming haploid spores.

QUESTION: The human naked eye can differentiate between two points which are how much apart?
A. 1 mm
B. 0.1 mm
C. 2 nm
D. 1 dm
EXPLANATION
The minimum capacity of a lens to distinguish between two adjacent points is called its resolving power. The resolution of the human naked eye is 0.1 mm according to the Federal Text Book.

QUESTION: Aschelminthes is also known as which of the following?
A. Protozoans
B. Eumetazoa
C. Proctoctist ancestors
D. Nematodes
EXPLANATION
Aschelminthes are also called nematodes.

QUESTION: The severe reduction in population size is due to which of the following?
A. genetic drift
B. outbreeding
C. inbreeding
D. bottleneck
EXPLANATION
The reduction of population size with some specific allele and genotype due to a natural disaster is called the bottleneck effect.

QUESTION: What is the function of the fluid secreted by the sertoli cells?
A. provides liquid medium
B. provides protection to sperms
C. provides nourishment to sperms
D. All A,B and C are correct
EXPLANATION
The fluid secreted by Sertoli cells provides liquid medium, protection and nourishment to sperms while they are in the tubules.

QUESTION: The membrane of vacuole is called:
A. Tonoplast
B. Plasma membrane
C. Epidermis
D. Both B and C
EXPLANATION
Tonoplast is the membrane of a vacuole

QUESTION: What type of molecule is Chlorophyll?
A. Inorganic
B. Cationic
C. Anionic
D. Organic
EXPLANATION
Chlorophyll is an organic molecule.

QUESTION: Intercostal muscles are found in:
A. Ribs
B. Pharynx
C. Lungs
D. Both B and C
EXPLANATION
The ribs are supported by intercostal muscles which form the walls of the thoracic cavity and also move the ribs during breathing.

QUESTION: Coenzyme Q is oxidized by which coenzyme in the ETC?
A. Coenzyme C
B. Coenzyme Q
C. Cytochrome B
D. Cytochrome A
EXPLANATION
NADH is oxidised by coenzyme Q, which is oxidised by cytochrome B.

QUESTION: What are the different stages of the calvin cycle?
A. Carbon fixation
B. RUBP
C. Reduction
D. A and C
EXPLANATION
The three stages of the Calvin Cycle are: carbon fixation, reduction and regeneration.

QUESTION: Which statement is incorrect?
A. Homologous organs are functionally different but structurally alike.
B. Examples of homologous structures are arms of man, forelimb of cat, flipper of whale.
C. Examples of analogous structures are wings of bats, birds and insects.
D. Analogous organs are functionally different but structurally alike.
EXPLANATION
Analogous organs are similar in function but different in structure. For example, the wings of a bird and a butterfly are analogous organs.

QUESTION: A scientist has discovered a new species of flower in which purple colouration is dominant to white. He wishes to know the genotype of a specific purple flower. Which of the following crosses would give him a definitive answer for the purple flower genotype?
A. Unknown purple X Homozygous purple
B. Unknown purple X Unknown Purple
C. Unknown purple X White
D. None of these
EXPLANATION
Option A will result in all purple offspring, which will not be useful. Option B can result in: EITHER All purple offspring. If this happens, we cannot tell which unknown purple flower was homozygous and which was heterozygous.  OR Purple and white offspring in a ratio of 3:1.  Thus, B would not give a definitive answer. Option C can result in: EITHER A 1:1 ratio of purple and white flowers. The unknown purple flower would be heterozygous.  OR All purple flowers. The unknown purple flower would be homozygous.  Thus only option C can give a definitive answer

QUESTION: The main transmitter for synapses that lie outside the central nervous system is?
A. adrenaline
B. serotonin
C. dopamine
D. acetylcholine
EXPLANATION
Acetylcholine is an excitatory neurotransmitter of the peripheral nervous system

QUESTION: The types of gametes produced by two pairs of chromosomes can be?
A. 2
B. 4
C. 6
D. 8
EXPLANATION
The number of combinations (types of gametes) possible for daughter cells formed by meiosis of a diploid cell with two pairs of homologous chromosomes (n = 2) is four: two possible arrangements for the first pair times two possible arrangements for the second pair.

QUESTION: What is the microscopes ability to distinguish between separate objects that are close together?
A. magnification
B. contrast
C. resolving power
D. scanning power
EXPLANATION
The minimum capacity of a lens to distinguish between two adjacent points is called its resolving power.

QUESTION: When was the agent causing AIDs discovered?
A. 1994
B. 1984
C. 1950
D. 1920
EXPLANATION
The AIDS virus (HIV) was discovered in 1984.

QUESTION: The path of electrons through the two photosystems is called?
A. S scheme
B. X scheme
C.  Z scheme
D. Y scheme
EXPLANATION
The path of electron transport through the two photosystems during noncyclic photophosphorylation is called the Z scheme due to its conceptual zigzag shape.

QUESTION: A metal cofactor which is used in synthesis of glycolysis is?
A. Fe+3
B. Mn+2
C. Co+2
D. Mg+2
EXPLANATION
Mg²+ is the cofactor used in the conversion of glucose to glucose-6-phosphate during glycolysis.

QUESTION: The sarcoplasmic reticulum is a special type of endoplasmic reticulum. Based on this information, which of the following is associated with a sarcoplasmic reticulum?
A. Network of tubules
B. Vesicles
C. Digestive Enzymes
D. Both A and B
EXPLANATION
ER is made up of a network of tubules and also has vesicles that transport processed molecules to a target location

QUESTION: Which one of the following statements about enzymes is not true?
A. They are sensitive to heat
B. They consist of proteins or without a non-proteins part
C. They change the rate of catalyzed reaction
D. They are non-specific in their action
EXPLANATION
Enzymes are highly specific in their action.

QUESTION: A muscular passage that is common to both food and air is known as
A. bronchi
B. broncioles
C. larynx
D. pharynx
EXPLANATION
The bronchi are the two branches of the lower end of the trachea, each leading into a lung. Bronchioles are finer branches of the bronchi inside the lungs. The larynx contains the vocal cords. The pharynx is a cone-shaped passageway leading from the oral and nasal cavities to the oesophagus and larynx

QUESTION: The place of centromere where spindle fibres get attached is?
A. Kinetochore
B. Tilomere
C. Centromere region
D. All of these
EXPLANATION
The spindle fibre attaches to the centromere at a proteinaceous structure called the kinetochore.

QUESTION: Midbrain is also known as:
A. Pons
B. Medulla
C. Mesencephalon
D. None of these
EXPLANATION
The midbrain is also known as the mesencephalon.

QUESTION: Neo Darwanism was developed in
A. early 1940s
B. early 1950s
C. early 1930s
D.  early 1960s
EXPLANATION
Neo-Darwinism developed in the early 1940s.

QUESTION: Assume that a trait is expressed according to the mechanism of complete dominance. Each gene contributes one of two possible alleles. Which of the following statements is true?
A. The genotype is the expressed trait of the individual
B. There are three possible phenotypes the organism can express
C. If two heterozygous organisms mate, 25% of the progeny will be
D. If two heterozygous organisms mate, 75% of the progeny will display the dominant phenotype.
EXPLANATION
If two heterozygous organisms mate, the phenotypic ratio of dominant and recessive offspring is 3:1.

QUESTION: The nitrifying bacteria are an example of which of the following?
A. Heterotrophic bacteria
B. Saprotrophic bacteria
C. Chemosynthetic bacteria
D. Parasitic bacteria
EXPLANATION
Chemosynthetic bacteria oxidise inorganic compounds like ammonia, nitrate, nitrite, sulphur or ferrous ions and use the energy thus released for their synthetic reactions. Nitrifying bacteria are chemosynthetic.

QUESTION: In myelinated neurons the impulse jumps from node to node, what is this transmission called?
A. myelinated impulse
B. jumping impulse
C. saltatory impulse
D. all of these
EXPLANATION
In myelinated neurons, the impulse jumps from node to node. This is called a saltatory impulse.

QUESTION: Malonic acid is an example of which type of inhibitors?
A. Irreversible Inhibitor
B. Reversible Inhibitor
C. Non-competitive Inhibitor
D. Competitive Inhibitor
EXPLANATION
Malonic acid (also called malonate) competitively inhibits the activity of the enzyme succinate dehydrogenase during the Krebs cycle.

QUESTION: A chromosome in which a centromere stays at one end is called?
A. Metacentric
B. Telocentric
C. Acrocentric
D. All of these
EXPLANATION
In a telocentric chromosome, the centromere is terminal (located at the very tip of the chromosome).

QUESTION: During inspiration, the diaphragm:
A. contracts
B. relaxes
C. contracts and relaxes
D. none of the above
EXPLANATION
Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges. This contraction creates a vacuum, which pulls air into the lungs. Upon exhalation, the diaphragm relaxes and returns to its domelike shape, and air is forced out of the lungs.

QUESTION: What allows a bacteria to stain positively with gram stain?
A. The bacteria is anaerobic
B. The bacterial sample was pretreated with 3% ethanol
C. The bacterias periplasmic space
D. The bacterias thick peptidoglycan cell walls
EXPLANATION
Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which allows them to take up the crystal violet colour of the Gram stain.

QUESTION: The brain portion that is reduced in humans is:
A. Forebrain
B. Midbrain
C. Hindbrain
D. Limbic System
EXPLANATION
The midbrain is much reduced in humans. It connects the hindbrain with the forebrain, receiving sensory information from the eyes, nose, ears and spinal cord and sending it to the forebrain for final processing and response.

QUESTION: Enzymes which control cellular respiration are present in?
A. mitochondria
B. nucleus
C. ribosomes
D. chloroplast
EXPLANATION
Glycolytic enzymes are present in the cytoplasm while the enzymes of the Krebs cycle are located in the mitochondrial matrix.

QUESTION: Unlike eukaryotes, prokaryotes have no membrane-bound organelles. How, then, are prokaryotes able to generate energy?
A. Prokaryotes generate sodium gradients across their nuclear membranes
B. Prokaryotes do not generate energy
C. Prokaryotes produce energy via photosynthesis
D. Prokaryotes generate proton gradients across their plasma membranes
EXPLANATION
Although prokaryotes lack mitochondria and other membrane-bound organelles, they are able to generate a proton gradient across their cell membranes, and thus produce ATP by chemiosmosis.

QUESTION: Which of the following viruses possess an envelope?
A. Herpes virus
B. Reovirus
C. TMV
D. Papillomavirus
EXPLANATION
The herpes virus is an enveloped, double-stranded DNA virus.

QUESTION: What is the viral nucleocapsid made up of?
A. genome and capsid
B. capsid and spikes
C. envelope and capsid
D. capsomeres and genome
EXPLANATION
The capsid is made up of units called capsomeres, and encloses the viral genome, which may be DNA or RNA.

QUESTION: Myosin filaments are contained within each:
A. Sarcomere
B. Microtubules
C. Filaments
D. M-line
EXPLANATION
Each sarcomere consists of light and dark bands. These bands are made up of actin and myosin filaments.

QUESTION: Most Carbondioxide is transported in the form of:
A. Carboxyhemoglobin
B. Plasma proteins
C. Bicarbonate ions
D. In dissolved form
EXPLANATION
70% of carbon dioxide is transported in the blood as bicarbonate ions, 23% as carboxyhemoglobin and 7% in water of plasma.

QUESTION: A person has a mutation that produces abnormal sarcoplasmic reticulum. Which of the following will not be a consequence of this mutation?
A. The myosin heads will not bind the actin filaments
B. Troponin will not be activated
C. Tropomyosin will remain bound to actin
D. Calcium ions will not be released into a synapse
EXPLANATION
The calcium ions required for muscle contraction are released from the SR while those involved in the transmission of an impulse across a synapse are released via vesicles in the presynaptic neuron.

QUESTION: The function of coelom is best characterized as?
A. To increase the size of the animals
B. To help in the functioning of the reproductive system
C. To provide space for the development of organs and systems
D. None of these
EXPLANATION
The coelom provides a space where internal organs can develop and function. For example, the pumping action of the heart is possible because of the surrounding space the coelom provides. The fluid-filled coelom also protects internal organs by cushioning them.

QUESTION: Enzymes are produced in inactive form by the cell and enclosed in which of the following?
A. Mesosomes
B. Lysosomes
C. Peroxisomes
D. All of these
EXPLANATION
Lysosomes are cell organelles that contain hydrolytic enzymes for intracellular digestion

QUESTION: When a hemophilia carrier woman marries a normal man, who among her offspring may be affected:
A. All her children
B. Half of her daughters
C. All her daughters
D. Half of her sons
EXPLANATION
Haemophilia is an X-linked recessive trait. This means that a carrier female will have one normal and one affected X chromosome. A normal male will quite obviously have a normal X chromosome. If we draw a Punnett square for this cross, we see that one son receives the affected X chromosome from his carrier mother and is thus a haemophiliac. The other son receives the normal X chromosome from his carrier mother and thus does not have the disease. Therefore, half of the carrier woman’s sons will be affected.

QUESTION: The brain area responsible for screening all incoming sensory data is:
A. Hypothalamus
B. Thalamus
C. Cerebellum
D. Cerebral Cortex
EXPLANATION
The thalamus receives sensory information from different parts of the brain, sorts them out and relays them to the appropriate part of the cerebral cortex for interpretation and response.

QUESTION: Each Krebs cycle forms how many molecules of NADH?
A. 3
B. 2
C. 4
D. 1
EXPLANATION
1 NADH molecule is produced at each of the following stages of a single Krebs cycle, therefore 3 NADH in total. Conversion of isocitrate to alpha-ketoglutarate Conversion of alpha-ketoglutarate to succinyl coA Conversion of malate to oxaloacetate

QUESTION: The diencephalon comprises of:
A. Pons and medulla
B. Thalamus and limbic system
C. Pons and medulla
D. Hypothalamus and limbic system
EXPLANATION
The forebrain is divided into two major regions - the upper telencephalon (cerebrum) and the lower diencephalon. The diencephalon is further subdivided into the thalamus and the limbic system.

QUESTION: Which of the following would most greatly increase the activity of an enzyme functioning in the small intestine?
A. decrease the temperature
B. increase the amount of enzymes
C. decrease the pH
D. increase the amount of substrate
EXPLANATION
A: Decreasing the temperature would decrease the rate of enzyme activity.  B: If there is unlimited availability of substrate, then increase in amount of enzyme can increase the activity of enzyme because more active sites would be available. But no such condition has been mentioned in the question.  C: The medium inside the small intestine is alkaline, therefore decreasing the pH would not increase enzyme activity. D: Usually, enzymes and substrates are present in moderate concentrations and a small amount of enzyme is required to convert a very large amount of substrate since the enzyme is not consumed and is used again and again. Therefore, in the scenario described in the question, D is the most suitable choice.

QUESTION: _______refers to the breakdown or removal of the capsid
A. assembly
B. uncoating
C. integration
D. maturation
EXPLANATION
Removal of the capsid or protein coat is called uncoating

QUESTION: Which one is not the characteristic of Kingdom Animalia?
A. All animals are ingestive heterotrophs
B. All animals are eukaryotes
C. It is the largest kingdom.
D. All animals develop from the dissimilar gametes i.e. large sperm and the small egg
EXPLANATION
The sperm is smaller in size than the ovum. A, B and C are true characteristics of animals.

QUESTION: The structures with a diameter less than 1mm are:
A. bronchioles
B. bronchi
C. alveoli
D. air sac
EXPLANATION
When the smaller bronchi attain a diameter of one mm or less, they are called bronchioles.

QUESTION: The maximum capacity of 100 ml blood to absorb oxygen is:
A. 10 ml
B. 20 ml
C. 30 ml
D. 45 ml
EXPLANATION
When oxygen tension is 115 mm mercury, haemoglobin is 98% saturated and therefore contains 19.6 (≈ 20) ml of oxygen per 100 ml of blood.

QUESTION: Which of the following is not an evidence for evolution?
A. Fossil record
B. Common ancestor organisms
C. Vestigial structures
D. None of these
EXPLANATION
Fossil records, common ancestor organisms and vestigial structures are all considered evidence for evolution.

QUESTION: If the cross-bridges bind to actin, they will pivot in such a way to cause the actin filaments to slide. This pivoting action causes the actin filaments to slide _______
A. closer together
B. farther apart
C. towards the Z-line
D. both B and C are correct
EXPLANATION
During a cross bridge cycle, the actin and myosin filaments slide inwards towards the centre of the sarcomere and the distance between adjacent Z lines decreases as a result. B and C mean the same thing - that the filaments slide away from the centre of the sarcomere, which is obviously incorrect.

QUESTION: Viruses without nuclear envelope is called as?
A. icosahedral virus
B. naked virus
C. enveloped virus
D. bilayer virus
EXPLANATION
A virus without the envelope is called a naked virus

QUESTION: Which condition can be explained by Lamarckism?
A. How giraffes got their long neck
B. How humans lost their tail
C. How humans became bipedal
D. All of these
EXPLANATION
According to Lamarck’s theory, evolution was driven by the use and disuse of organs. All the three options can be explained by Lamarckism.

QUESTION: Which of the following plays vital role in defense activity of macrophages?
A. Lysozymes
B. Lysosomes
C. Mitochondria
D. Nucleus
EXPLANATION
Macrophages are phagocytes and need to carry out intracellular digestion, which is the function of lysosomes.

QUESTION: The follicle cells, after release of the egg, are modified to form a special structure called:
A. Endometrium
B. Perimetrium
C. Corpus Luteum
D. None of these
EXPLANATION
During each menstrual cycle, usually only one of the many primary follicles (or “ovarian follicles”) matures to form a Graafian follicle, which contains the mature ovum. During ovulation, the ovum is released and the empty Graafian follicle forms a yellowish endocrine tissue called the corpus luteum.

QUESTION: The soluble sap of the nucleus in a plant cell is called?
A. cytoplasm
B. nucleoplasm
C. protoplasm
D. protoplast
EXPLANATION
The nucleoplasm is a gel-like, protein-rich substance present in the nucleus.

QUESTION: All of the following statements are correct EXCEPT:
A. The testicles produce millions of sperm.
B. Hormones are produced by the testicles.
C. Semen is produced in the seminal vesicles
D. All males are born with one testicle
EXPLANATION
Human males have two testes (a testis within a scrotum is called a testicle).

QUESTION: Esters of fatty acids with higher alcohols other than glycerol are called _______
A. Waxes
B. Fats
C. Both A and B
D. None of these
EXPLANATION
Fats (acylglycerol) are esters of fatty acids and glycerol. Natural waxes are esters of long-chain fatty acids and long-chain alcohols.

QUESTION: A giant micro organism, which was discovered in the intestine of brown surgeonfish (Acanthurus nigrofuscus), is:
A. a bacterium
B. a virus
C. a parasite
D. protozoa
EXPLANATION
Epulopiscium fishelsoni is a very large bacterium that only lives in the gut of a brown surgeonfish found in the Red Sea.

QUESTION: K.E of the liquids is directly proportional to ____?
A. Pressure
B. Temperature
C. Mass
D. Nature
EXPLANATION
When the temperature of molecules increases, they gain energy and move and collide more, hence temperature is directly proportional to temperature. The energy they gain is kinetic energy.

QUESTION: Specific Rate constant is also known as ?
A. Time Constant
B. relative rate constant
C. Instantaneous rate constant
D. velocity constant
EXPLANATION
rate=k(a)(b) Where k is the rate constant in the rate equation. Where velocity constant is another name of K. it is dependent upon the temperature and temperature is directly proportional to velocity.

QUESTION: Methanol is also called as?
A. liquor
B. grain alcohol
C. wood spirit
D. fuel
EXPLANATION
Methanol has the formula CH2OH. It is known as wood alcohol because it was once produced by the destructive distillation ( decomposition of wood at high temperatures without the presence of air) of wood.

QUESTION: The mass of one mole of electron is ?
A. 1.8mg
B. 0.184mg
C. 0.55mg
D. 0.64mg
EXPLANATION
We know that mass of an electron = 9.1x10-31 Avagadros constant = 6.02x1023 Mass of 1 mole electron= 9.1x10-31 x 6.02x10-23 = 5.48x10-7 kg hence = 5.48x10-7 x 1000000= 0.55mg

QUESTION: What is the coordination number of Cu metal in [Cu(NH3)4]S04?
A. 3
B. 4
C. 6
D. 1
EXPLANATION
The Coordination number of an atom in a given molecule or a crystal refers to the total number of atoms, ion, or molecules bonded to the atom in question. The atoms, ions, or molecules that are bonded to the central atom (or molecule/ion) are called ligands. Since 4 NH3 molecules are bonded to Cu the coordination number of copper in [Cu(NH3)4]2+ is 4.

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
It shows a free radical substitution reaction in which UV light (sunlight) is used to substitute the Hs of the CH4. Either all of the Hs can be substituted (eg: CCl4 ), or some of the Hs (eg: CHCl3) can be substituted.

QUESTION: Which of the following element is not usually present in all proteins?
A. Carbon
B. Hydrogen
C. Nitrogen
D. Sulphur
EXPLANATION
Proteins are made up of amino acids. Amino acids have the formula H2NC(R)(OOH), hence carbon, hydrogen, and nitrogen will always be present in the proteins. Sulphur may or may not be present.

QUESTION: Arrangement of atoms in Molecular Solids can be studied with the help of?
A. Gamma Rays
B. X-Rays
C. Spectrometry
D. Electron Microscope
EXPLANATION
X-ray crystallography is a method of determining the 3d arrangement of atoms within a molecule. Hence the arrangements of atoms in the solids can be determined using x rays.

QUESTION: Which one is not a member of Alkali metals?
A. Na
B. K
C. Cs
D. Mg
EXPLANATION
Alkali metals are group 1 metals and Mg is in group 2 and the rest of the three options are elements from group 1.

QUESTION: Isopentane is an example of ____ ?
A. Aromatic compounds
B. Branched-chain compound
C. Alicyclic compounds
D. None of these
EXPLANATION
Alicyclic compounds are 3 or more atoms of carbon are linked together in a ring. Aromatic compounds are those that are cyclic and have delocalized electrons in the ring = benzene. Hence isopentane is not a ring compound or has a benzene ring hence it can only be a branched-chain compound.

QUESTION: The compounds which are formed by the replacement of a hydrogen atom by a halogen are called as_?
A. Alcohol
B. Alkyl halide
C. Carbonyl halide
D. Ethers
EXPLANATION
Alkyl halides are also known as halogenoalkanes are formed when a hydrogen atom is removed from an alkene/alkane are known as alkyl halides while carbonyl halides are those in which a halogen replaces a hydroxyl group.

QUESTION: Which of the following is applicable for phenols?
A. a colourless crystalline solid
B. more reactive to nucleophillic attack
C. form link solution at room temperature
D. dissolves readily in alkalines
EXPLANATION
The OH group of phenol determines its properties. The OH group makes the phenol acidic and hence the acidic property allows it to dissolve readily in alkalines.

QUESTION: Which of the following reaction is used to produce symmetrical alkanes from alkyl halides?
A. Wittig reaction
B. Kolbes electrolysis
C. Reduction of alkyl halide
D. Wurtz reaction
EXPLANATION
Wurtz reaction is the one in which longer chain alkanes are made from two different alkyl halides coupling together with the help of sodium and dry ether. This reaction is used to produce symmetrical alkanes with a greater number of carbons. Because a methane chloride cannot be used to make butane while ethane chloride can be used to produce butane hance can only symmetrical alkanes.

QUESTION: In a homologous series, adjacent members differ by a _____ unit?
A. CH3
B. CH2
C. CH
D. CH4
EXPLANATION
CH4, C2H6, and C3H8 are all consecutive alkanes in the homologous series, each differing from the next and previous compound by the presence and absence of one CH2 (methylene) group.

QUESTION: In Electrochemical Cells Reduction takes place at?
A. Anode
B. Cathode
C. At the surface of electrolyte
D. None of these
EXPLANATION
In an electrochemical cell, the cathode (+) is the one that gains electrons hence the element that is being reduced gains electrons. Eg; cu2+ + 2e = cu STANDARD C3ELL (E)= +0.34v 2H+ +2e= H2 E=0.00V cu2+ is being reduced because it is more positive hence moves forward and hence is gains electrons, hence it will be on the cathode because it gains electrons

QUESTION: If the difference of electronegativity is 1.7 or more than that, the bond formed is said to be:
A. Ionic bond
B. Covalent bond
C. Metallic bond
D. Chemical bond
EXPLANATION
In covalent bonding, the electronegativity difference is very less from 0 to 1 max. Metallic bonding is found in metals and does not depend on electronegativity differences. The chemical bond is between ions, elements, molecules. Ionic bonding has the greatest electronegativity difference as it is between metals and non-metals.

QUESTION: What pressure of oxygen is maintained inside the bomb calorimeter?
A. 200 atm
B. 25 atm
C. 20 atm
D. 75 atm
EXPLANATION
High-Pressure oxygen is required to ensure the sample burns completely in the bomb vessel. The oxygen assists with the burning of the sample to ensure the sample burns completely for an accurate final result. The Federal Book says 25 atm, while PTB says 20 atm. Since the MDCAT is national this year, 25 atm should be the primary answer. This is an official question from PMC and both 20 and 25 were there in the options.

QUESTION: Find the amphoteric oxide.
A. CaO2
B. CO2
C. SnO2
D. SiO2
EXPLANATION
CaO is basic oxide. SiO2 is acidic oxide hence cannot be a or d CO2 is acidic hence cannot be b. Hence SnO2 is the only amphoteric.

QUESTION: The reactant which is consumed completely in a reaction is known as the ______ reactant.
A. Fractional
B. Initial
C. Limiting
D. Minor
EXPLANATION
The reactant that is in the least amount in the reaction and consumed first is called the limiting reactant.

QUESTION: If Ammonia is not withdrawn continuously from equilibrium mixture its yield will be?
A. increased
B. decreased
C. remain unchanged
D. None of these
EXPLANATION
The formation of ammonia is a reversible reaction. 3H2 + N2= 2NH3 So if the ammonia is not removed from the reaction mixture, the equilibrium will counteract to oppose the change hence equilibrium moved backward and hence less ammonia will be made.

QUESTION: Adhesive nature of honey and glue is due to the presence of?
A. H-bonding
B. Dipole dipole forces
C. Ionic forces
D. Debye force
EXPLANATION
Glue is made of PVA and water molecules. The oxygen in water molecules has lone pairs that can form hydrogen bonds with the h of another molecule. Honey is made of glucose and fructose hence h- bonds form between H of the glucose and fructose and the lone pairs of oxygen.

QUESTION: Which of the following compounds are added to ethanol to make it unfit for drinking?
A. Pyridine
B. Methanol
C. Acetone
D. All of these options are correct
EXPLANATION
Although Pyridine is used in some medicines and flavorings as a solvent, it is also a main constituent for toxic substances like dyes, therefore the ingestion of pyridine could cause irritation, inflammation, dizziness, and even coma leading to death. Methanol is common rubbing alcohol which is poisonous for the body and can cause death if ingested.  Acetone is the main constituent of nail paint removers, its fumes being so toxic that mass inhalation can cause a fatal coma.

QUESTION: Formaldehyde is used in vat dyeing as?
A. Coloring agent
B. Dehydrating agent
C. Decolorizing agent
D. solubilizing agent
EXPLANATION
Formaldehyde is used in the synthesis of dye fixing agents in dyeing. Also used in disperse dyeing

QUESTION: Propanoic acid is produced when _______.
A. Methyl MgBr reacts with CO2
B. Isopropyl MgBr reacts with CO2
C. Ethyl MgBr reacts with CO2
D. Propyl MgBr reacts with CO2
EXPLANATION
Propanoic acid has only 3 carbons. Hence it cannot be made from propyl MgBr2. The R group of the MgBr2 attaches to the carbon of CO2.  The reaction is: CH3CH2MgBr + CO2 = CH3CH2CO2H + MgBr2. The compound formed is propanoic acid.

QUESTION: Which of the following shows tautomerism?
A. Amino acids
B. Ketones
C. Carboxylic acids
D. All of these options are correct
EXPLANATION
Tautomerism is when a carbon-carbon double bond is shifted to another atom. In the given options all of the options has a C=O or C=C hence, the answer is D. The compound formed has the same molecular formula but a different arrangement.

QUESTION: Which of the following process is used to improve the quality of Gasoline?
A. Steam cracking
B. Reforming
C. Catalytic cracking
D. Distillation
EXPLANATION
Reforming is a process designed to increase the volume of gasoline that can be produced from a barrel of crude oil. It is used to improve the quality to make more gasoline.

QUESTION: The solubility of alcohols is due to?
A. dipole moment
B. covalent bonds
C. hydrogen bonding
D. electronegativity
EXPLANATION
Alcohols have OH in which O has a lone pair hence can easily form hydrogen bonds with the H of water molecules. It dissolves in a polar solute by forming hydrogen bonds.

QUESTION: Kinetic Energy is the sum of?
A. Rotational & Vibrational
B. Translation & Rotational
C. Rotational, Vibrational, and Translation
D. All of these
EXPLANATION
The kinetic energy of an object with translational and rotational motion is the sum of its translational and its rotational kinetic energy. Molecules vibrate when they gain kinetic energy hence, vibrational rotation as well.

QUESTION: In which of the following reaction rate of reaction is not affected by increasing concentration of nucleophile?
A. SN2
B. E2
C. SN1
D. None of these
EXPLANATION
The SN1 mechanism is a ttwo-stepmechanism in which the rate is dependent on the halogenoalkane and not the nucleophile. Hence no matter how much we increase the reactant that is the nucleophile it will have no effect on the rate.

QUESTION: The law of conservation of energy is actually?
A. Second law of thermodynamics
B. Third law of thermodynamics
C. First law of thermodynamics
D. Zeroth law of thermodynamics
EXPLANATION
The law of conservation of energy states that the energy is always conserved in a closed system. The first law of thermodynamics is that change in internal energy = heat energy supplied to the system + work done on the system. Hence in both cases, the total energy is conserved.

QUESTION: When the central atom of the coordination compound is sp3d2 hybridization, the expected geometry will be?
A. Tetrahedral
B. Square planar
C. Trigonal bipyramidal
D. Octahedral
EXPLANATION
The sp3d2 hybridization leads to a central metal that has an octahedral geometry.

QUESTION: Base catalyzed reaction of carbonyl group takes place in the presence of:
A. Weak electrophile
B. Strong nucleophile
C. Weak nucleophile
D. Strong electrophile
EXPLANATION
For all carbonyl compounds, nucleophilic addition reactions take place, and hence a strong nucleophile that can break the C=O bond and is negatively charged is used.

QUESTION: Brittleness of ionic solids is due to the fact that ions arrange themselves in a way to _______ each other.
A. Attract
B. Compress
C. Repel
D. Overlap
EXPLANATION
To an ionic compound when a force is applied, like charges in the lattice come together due to the force applied and repel each other, breaking the compound hence ionic compounds are brittle, as like charges repel.

QUESTION: The rate equation is a(n):
A. Experimental expression
B. Theoretical expression
C. Based on hit and trial
D. All of these options are correct
EXPLANATION
We take readings after doing 2-3 experiments and then find the order of the reaction and then make the equation for the rate.

QUESTION: Salt Bridge contains ?
A. Aqueous Calcium Chloride
B. Molten zinc powder
C. KCl in a gel
D. NaCl in a gel
EXPLANATION
A saturated solution of KCl is used in making salt bridges. Because it is relatively inert. Mostly inert electrolytes are used in salt bridges.

QUESTION: In energy terms, the elements at high energy state are?
A. electronegative elements
B. electropositive elements
C. neutral elements
D. charged elements.
EXPLANATION
Electropositivity is a character of metals that tend to lose electrons to attain stability because at the initial stage (before losing electrons) the metal is unstable (unstable is directly proportional to energy ) so they have high energy.

QUESTION: If uncertainty in the momentum of electron is zero, the uncertainty in its position would be ___?
A. Less than zero
B. more than zero
C. one
D. infinite
EXPLANATION
Heisenberg Uncertainty Principle. It states that the position and the velocity of an object cannot both be measured exactly, at the same time, even in theory. Hence, for any object, at a given point in time, the position of the object can be found if the momentum is not found. And vice versa.

QUESTION: In non-polar molecules ,the strength of London forces depends on number of?
A. moles
B. molecules
C. atoms
D. all of these
EXPLANATION
In nonpolar molecules, there are induced dipole-dipole forces and its strength is dependent on the number of electrons hence the number of atoms. Greater the number of electrons stronger the dipole-dipole force.

QUESTION: Nitrogen N2 has ______ number of electrons, protons and neutrons.
A. 7, 8, 9
B. 7, 7, 7
C. 14, 14, 14
D. 14, 14, 15
EXPLANATION
N2 has an Atomic Number of 7 and Mass Number of 14. The Atomic Number (Z) is the number of protons OR electrons possessed by an atom. The Mass Number (A) is the total number of nucleons (protons + neutrons) in the nucleus of an atom. As Z=7, the number of electrons is also 7 and as the number of electrons is equal to the number of protons for a neutral atom, the number of protons is also 7 for Nitrogen.  The number of neutrons is determined by: No. of Neutrons = A-Z = 14-7 = 7.

QUESTION: Which of the following properties is not related to transition metals ___ ?
A. Complex formation
B. Color
C. Fixed valency
D. d-orbital
EXPLANATION
Transition elements form complex ions by bonding dative bonds with the ligands. They are colored compounds and have d orbitals hence the only incorrect option is C.

QUESTION: The bonding pair of electron are equally shared b/w the atoms in?
A. HF
B. HCl
C. H20
D. H2
EXPLANATION
H2 has 1 electron hence the two equally share the electron and have zero electronegativity difference hence are nonpolar.

QUESTION: Which of the following catalyst is used in the industrial preparation of methanol?
A. Zinc oxide and alumina
B. Alumina and silica
C. Silica and chromium oxide
D. Zinc oxide and chromium oxide
EXPLANATION
The dominant catalyst formulation for methanol synthesis is Cu/ZnO with a molar ratio of Cu/Zn in the range 2–3 and some alumina that acts as a structural promoter. These catalysts are also active for the water gas shift reaction which makes it possible to produce methanol from CO2.

QUESTION: Self-oxidation reduction reaction is also called as ______?
A. Dehydration
B. Condensation reaction
C. Disproportionation reaction
D. Proportionation reaction
EXPLANATION
In chemistry, disproportionation, sometimes called dismutation, is a redox reaction in which one compound of intermediate oxidation state converts to two compounds, one of higher and one of lower oxidation states.

QUESTION: In Electrolysis of NaNO3, Na+ is:
A. Discharged at anode
B. Discharged at cathode
C. Does not discharge
D. None of these options is correct
EXPLANATION
Once its aqueous, the Na+ and NO3– will compete with water which is H2O. The anion will be attracted to the cathode and the cation will be attracted to the anode.  The anion of aqueous NaNO3 is H2O and Na+ ion. Since H2O is stronger than Na+ ion, H2O is chosen and reduced to hydroxide and hydrogen gas. At the anode, H2O is not chosen because H2O is weaker than NO3–. NO3– is oxidized to nitrogen monoxide and 2 moles of water.

QUESTION: Which of the following flavour is due to Amyl acetate ?
A. Jasmine
B. Pineapple
C. Banana
D. Orange
EXPLANATION
Amyl acetate (A-mil AS-uh-tate) is a colorless liquid with a distinctive banana-like flavor and odor.

QUESTION: The only thing which can predict that if the reaction will be spontaneous or nonspontaneous is:
A. Enthalpy change
B. Free energy of the system
C. Energy Change
D. Temperature Change
EXPLANATION
Free energy of the system also known as the Gibbs free energy determines if the reaction is spontaneous or not. The formula for Gibss free reaction = enthalpy change- T(entropy change). If Gibbs free reaction is 0 or less, then the reaction is spontaneous.

QUESTION: Which of the following shows H bonding?
A.  CH3CH2OH
B. CH3-O-CH3
C. CH3CH2Cl
D. All of these
EXPLANATION
Compounds with both H and O form hydrogen bonds.

QUESTION: Vital Force Theory was proposed by?
A. Wohler
B. Berzelius
C. Kesley
D. Lyll
EXPLANATION
According to the vital source theory, organic compounds must have their origin in living organisms and could not be synthesized by inorganic compounds. It was proposed by Jöns Jacob Berzelius in the 19th century.

QUESTION: Alkali and alkaline earth metals impart colours when heated over the burner, it is due to?
A. Smaller electronegativity of alkali metals
B. The smaller ionic radius of these metals
C. De-excitation of electrons from higher energy levels to lower energy levels
D. Excitation of electrons from low energy levels to higher energy levels
EXPLANATION
Alkali metals have low ionization energies. The energy from the flame is sufficient to excite electrons to a higher energy level. The excited state is unstable hence, electrons emit energy and come back to their original levels. These energies fall in the visible light region hence the burner has color as excited electrons lose energy and become de-excited.

QUESTION: Which one of them belongs to the tetragonal system?
A. Bi
B. Sn
C. Fe
D. Zn
EXPLANATION
The tetragonal system is a crystal system in which the unit cell of the lattice is a right prism on a square base (a=b). The characteristic symmetry element is a 4-fold axis: A4. There are 7 crystal classes in this system. Zn, Fe and Bi are metallic lattices.

QUESTION: Which of the following is a slow step in SN1 reactions?
A. Ionization
B. Formation of carbocation
C. Formation of Double bond
D. Formation of alkyl halide from carbocation
EXPLANATION
The formation of a carbocation is the slow, or rate-determining, step. The subsequent step, formation of a bond between the nucleophile and the carbocation, occurs very rapidly. Because the slow step of the reaction involves only the substrate, the reaction is unimolecular.

QUESTION: Kinetic molecular theory was proposed by?
A. Berzelius
B. Boltzmann
C. Bernoulli
D. Maxwell
EXPLANATION
Over four hundred years, scientists including Rudolf Clausius and James Clerk Maxwell developed the kinetic-molecular theory (KMT) of gases, which describes how molecule properties relate to the macroscopic behaviors of an ideal gas—a theoretical gas that always obeys the ideal gas equation.

QUESTION: Proteases enzyme are example of?
A. Lyases
B. Hydrolases
C. Ligases
D. Transferases
EXPLANATION
Protease is an enzyme that hydrolyses the protein into amino acids. Hence it is a hydrolases enzyme.

QUESTION: The catalyst in the formation of ester from alcohol and a weak acid is?
A. A base
B. Palladium
C. Nickel
D. A mineral acid
EXPLANATION
Carboxylic Acids, on being heated with alcohols produce esters. The catalyst in the reaction is concentrated sulphuric acid.

QUESTION: Choose the one which is not an assumption of the collision theory of reaction rate:
A. For chemical reaction to occur molecules/particles must collide
B. For reacting molecules/particles must possess a certain minimum amount of energy which is the activation energy
C. For hydrogen molecule formation, atoms require specific orientation
D. Every collision is not productive
EXPLANATION
Collision molecular theory says that for a reaction to occur, reactants must collide in a specific orientation with a specific energy. As hydrogen is a diatomic molecule so it does not require a specific orientation.

QUESTION: Radar is an application of which effect?
A. Dopplers effect
B. Magnetic effect
C. Mechanical effect
D. Electrical effect
EXPLANATION
Doppler Effect refers to the change in wave frequency during the relative motion between a wave source and its observer. Doppler effect is used to measure speed in RADAR sensors. When the fixed-frequency radio wave sent from the sender continuously strikes an object that is moving towards or away from the sender, the frequency of the reflected radio wave will be changed which is why the answer is A.

QUESTION: Electric power is
A. Rate of electric work done per unit time
B. Voltage per unit time
C. Electric charge per unit time
D. Current per unit time
EXPLANATION
Power=work done/time so electrical power is the rate of electrical work done per unit time so the answer is A.

QUESTION: Which of the following is equivalent to a temperature of 150K?
A. 123⁰C
B. -123⁰C
C. 423⁰C
D. -423⁰C
EXPLANATION
Temperature in degrees Celsius + 273= Temperature in Kelvin x+273=150 x= -273+150 x= -123 C which is option B.

QUESTION: Which of the following is not a conservative force?
A. Friction
B. Electric
C. Magnetic
D. Gravitational
EXPLANATION
A conservative force is a force applied in moving a particle from one point to another, such that the net amount of force is independent of the path taken by the particle. Friction is non-conservative because the amount of work done by friction depends on the path. The longer the path, the more the friction. Hence the answer is B.

QUESTION: Which of the following frequency of sound waves is audible?
A. 5Hz
B. 5000Hz
C. 2500kHz
D. 50kHz
EXPLANATION
The audible frequency for humans is 20hz-20,000Hz. Since option B is the only one that falls in this range, it is the only correct answer.

QUESTION: The maximum velocity of SHM is ao. The period of oscillation is:
A. 2π xo/ao
B. 2π ao/xo
C. 2π xoao
D. 2π / xoao
EXPLANATION
In SHM, the maximum velocity is given by: Vmax = ωxo   where ω = 2 π / T and Vmax = ao , so ao = (2π / T) xo T = 2πxo/ ao so the answer is A.

QUESTION: A 250 V bulb passes a current of 0.3 A. Calculate the power in the lamp.
A. 50 W
B. 75 W
C. 100 W
D. 90 W
EXPLANATION
Power = voltage x current  P= 250 x 0.3  P= 75 W (option B)

QUESTION: What is the unit of decay constant?
A. Second
B. Minute
C. Hour
D. Sec-1
EXPLANATION
Decay constant is the rate of decay of a sample per unit time and the units are sec-1 so it is D.

QUESTION: The unit of velocity is:
A. m s
B. m/s
C. m
D. m/s2
EXPLANATION
Velocity= displacement/time or V = m/s Which is option B.

QUESTION: Isotopes of an element have different number of
A. protons
B. neutrons
C. electrons
D. atom
EXPLANATION
Isotopes are elements with the same proton and electron number but different neutrons so option B is correct.  Difference of protons causes difference in type of elements, and difference in electrons causes formation of ions.

QUESTION: Equal masses of paraffin wax and water are mixed in a container of negligible thermal capacity. If the initial temperature of water is 80c and that of wax is 20C, what is the final temperature of the mixture?
A. 70c
B. 60C
C. 50C
D. 40C
EXPLANATION
80+20/2= 50 degrees. (no specific heat capacity mentioned)

QUESTION: Two incandescent light bulbs of 40 W and 60 W are connected in series across the mains. Then:
A. The bulbs together consume 100 W
B. The bulbs together consume 50 W
C. The 60 W bulb glows brighter
D. The 40 W bulb glows brighter
EXPLANATION
When two bulbs are connected in series, the current will be the same but the resistance will vary. The higher the resistance, the brighter the bulb. And resistance is inversely proportional to power so the bulb with the higher power, in this case, 60 W, has low resistance so it will be less bright than the 40 W bulb so the answer is D.

QUESTION: Which radiation is used in greenhoue effect?
A. UV
B. IR
C. X rays
D. gamma rays
EXPLANATION
The greenhouse effect is when some of the infrared radiation (IR) from the Sun passes through the atmosphere, but most is absorbed and re-emitted in all directions by greenhouse gas molecules and clouds. The effect of this is to warm the Earths surface and in the lower atmosphere.

QUESTION: For a coil self inductance is L and current is I then flux passing through it is:
A. LI
B. LI^2
C. L^2I
D. (LI)^2
EXPLANATION
Self inductance=flux/current L= flux/I so flux= L x I. (Option A)

QUESTION: displacement of an object in moving around a complete circle is:
A. 2pi r
B. 2r
C. pi r
D. zero
EXPLANATION
Displacement is a vector quantity so it depends on direction and in a circle the initial point is the same as the final position so the net displacement is zero which is option D.

QUESTION: When a body moves in a circle of radius r with angular speed w, its centripetal acceleration is:
A. wr
B. rw^2
C. wr^2
D. w/r
EXPLANATION
The centripetal acceleration formula is w^2 x r so the correct answer is B

QUESTION: Transformation ratio of transformer is given by:
A. Vs/Vp
B. IpIs
C. NsNp
D. all of these
EXPLANATION
The transformation ratio is defined as the ratio of output voltage to the input voltage of the transformer. Vs is output voltage (secondary) and Vp is the input voltage (primary voltage).

QUESTION: The distance between two consecutive crests in a stationery wave is:
A. 1 wavelength
B. 3/4 wavelength
C. 1/2 wavelength
D. 3/2 wavelength
EXPLANATION
Distance between two consecutive crests or two consecutive troughs in any wave is equal to one wavelength. Distance between a crest and its adjacent trough is equal to half wavelength. Distance between two consecutive nodes or two consecutive antinodes is equal to half wavelength.  Distance between a node and its adjacent antinode is is equal to 1/4th of wavelenght.

QUESTION: A light bulb draws 300 mA when the voltage across it is 240V. The resistance of the light bulb is:
A. 400 ohm
B. 600 ohm
C. 800 ohm
D. 1000 ohm
EXPLANATION
R=V/I 240 / 300 x10^-3 800 ohms (option C)

QUESTION: A constant force of F=(i-2j-3k) causes a displacement d=(2i-5j=k), what will be the net workdone if f is in N and displacement is in meters?
A. 15 J
B. 9 J
C. 8 J
D. 18 J
EXPLANATION
Work done= force x distance (i-2j-3k)(2i-5j+k) multiply the coefficients of i then j then k and add them. (1x2) + (-2x-5) + (-3x1) w.d= 2+10+(-3) = 9 J

QUESTION: If a squash ball comes to its starting point after bouncing off the wall several times, then...
A. Its total displacement is zero but its average velocity is non zero.
EXPLANATION
Since the initial point and final position are the same, the net displacement is zero and velocity is, in essence, the change in displacement over time so, if the displacement is 0, then the velocity is zero too so, D is the correct option.

QUESTION: Two spheres are made of same metal and have the same radius, but one is hollow and the other is solid. The spheres are taken through same temperature increase. Which sphere expands more?
A. They expand by the same amount.
B. The hollow sphere expands more.
C. The solid sphere expands more.
D. There is not information to say.
EXPLANATION
The formula for cubical expansion is change in volume= cubical expansion coefficient x initial volume x change in temperature. Since the materials are the same, the cubical expansion coefficient will be the same. The radius for both of the spheres is the same so the initial volume is also the same. And the question states that they go through the same temperature change hence the spheres will go through the same expansion so the answer is A.

QUESTION: Static charge always creates
A. electric feld and magnetic field
B. magnetic field
C. electric field
D. both a and b
EXPLANATION
A static charge produces an electric field. A moving charge produces a magnetic field. Electromagnetic waves are produced by an accelerating charge so the answer is C.

QUESTION: The minimum indivisible unit of charge is:
A. 1 coloumb
B. charge on on alpha particle
EXPLANATION
The smallest indivisible unit of charge is one electron, which is equal to charge of one proton. So the option is C. The minimum charge is that of an electron: 1.6 x 10-19 C.

QUESTION: Solar spectrum is a type of
A. continuous
B. discrete
C. both a and b
D. none of these
EXPLANATION
The solar spectrum consists of a bright coloured continuous spectrum interspersed with dark lines so the answer is A.

QUESTION: A heat engine performs 100 j of work and at the same time rejects 400 J of heat energy to cold reservoirs. What is the efficiency of the engine?
A. 20%
B. 25%
C. 4%
D. 50%
EXPLANATION
Formula for efficiency is Efficiency = W / Q1 W = Q1 - Q2 Work = 100 Q2= 400 J 100=q1-400 Q1= 500 J Efficiency = 100/400 = 0.2 x 100= 20%

QUESTION: In a stationery wave, the phase angle between a node and a consecutive antinode is:
A. 90 degree
B. 180 degreee
C. 270 degree
D. 150 degree
EXPLANATION
The ange between node and antinode is 90 degree. The angle between two nodes or two antinodes (or adjacent crests and troughs) is 180 degree. The angke between two crests (or two troughs) is 360 degree. 1 wavelength is equal to 360 degree. 3/4 wavelength is equal to 270 degree. 1/2 wavelength is equal to 180 degree 1/4 wavelength is equal to 90 degree.

QUESTION: When are x-rays used in crystallography?
A. to prevent interference
B. to prevent diffraction
C. to perform interference
D. to perform diffraction
EXPLANATION
X-ray beams are used to determine the structure of the crystal. The crystal diffracts the X-ray beams and the intensities and angle of diffraction of these diffracted beams is studied to estimate the structure of the crystal so the answer is D.

QUESTION: A 4kg eagle picks up a 75g snake and raises it 2.5 m from the ground to a branch. What is the workdone by the eagle on the snake? (g=10m/s2)
A. 100 J
B. 1.875 J
C. 18.75 J
D. 187.5 J
EXPLANATION
W.d= force x distance f= mg ; mass of snake will be used as work is being done on it and we should convert it to kg so m, 0.075 kg x 10 = 0.75 N. w.d= 0.75 x 2.5 = 1.875 J (option B).

QUESTION: EMF becomes equal to terminal potential difference when
A. circuit is closed
B. current is max
C. circuit is open
D. all of these
EXPLANATION
Electromotive force (EMF) is equal to the terminal potential difference when no current flows and In the open circuit the current can not flow from one end of the power source to the other so the answer is C.  (note: circuit is open means that the switch is turned off.)

QUESTION: The existance of positron is discovered in the:
A. thermal radiation
B. cosmic radiation
C. electromagnetic radiation
D. non-electromagnetic radiation
EXPLANATION
Carl Anderson was studying the showers of cosmic particles and discovered positrons in 1932.

QUESTION: the linear acceleration of a body moving in a circular path is:
A. negative
B. positive
C. constant
D. zero
EXPLANATION
Linear acceleration, also known as tangential acceleration, is zero when a body is moving in a circular path because the object has constant speed. (note: the question does not provide complete information. It should be mentioned in the question that the body is moving in a constant speed. Otherwise, linear acceleration exists in circular motion as well.)

QUESTION: Most widely used rectifier is:
A. half wave rectifier
B. full wave rectifier
C. bridge rectifier
D. none of them
EXPLANATION
Bridge rectifier is the most commonly used rectifier in electronics.

QUESTION: The artifacts and fossils are used to estimate ages by measuring ________ content.
A. mineral
B. chemical
C. radioactive
D. all of these
EXPLANATION
Radiometric dating, which relies on the predictable decay of radioactive isotopes of carbon, uranium, potassium, and other elements, provides accurate age estimates for artifacts and fossils.

QUESTION: One proton beam enters in a magnetic field of 10-4 T normally with specific charge 1011 C/kg and velocity of 107 m/s. What will be the radius of circle?
A. 0.1 m
B. 1 m
C. 10 m
D. none of them
EXPLANATION
r= mv/Bq R = 10^7 / (10^11) x (10^-4) r= 1m.

QUESTION: The shortest distance between two points on the wave that have a phase difference of (pi/3) is 5 cm. What is its wavelength?
A. 10 cm
B. 20 cm
C. 30 cm
D. 40 cm
EXPLANATION
Phase difference = 2π/λ x path difference. π/3 = 2π/λ x 5 λ= 2 x 3 x 5 = 30 cm

QUESTION: Electrostatic force is:
A. nonconservative
B. conservative
C. depends upon the shape of charge
D. none of these
EXPLANATION
Work done by the electrostatic force is independent of the path followed by it, and it depends only on the initial and final positions. So,electrostatic force is a conservative force.

QUESTION: Transistors can be:
A. half wave rectifier
B. full wave rectifier
C. both
D. none
EXPLANATION
Transistor can be used as a switch for opening and closing of the circuit. A transistor can also act as an amplifier, but not rectifier Since none of these answers are in the options, the answer is D.

QUESTION: Number of photo electrons emitted from metal depends upon:
A. intensity of incident light
B. enery of incident light
EXPLANATION
The number of electrons is proportional to the light intensity (at a fixed wavelength) and independent of the frequency of the incident radiation above threshold so the answer is A.

QUESTION: A bullet of mass 5x10-5 has te velocity of 200 m/s, kinetic energy of bullet is:
A. 100 J
B. 1000 J
C. 10 J
D. none of these
EXPLANATION
K.E = ½ x m x v^2 ½ x (5x10^-5)(200)^2 = 1000J.

QUESTION: What is the frequency of a photon whose energy is 66.3 eV?
A. 12.6 x 106 Hz
B. 19.6 x 106 Hz
C. 1.6 x 1016 Hz
D. 81.6 x 106 Hz
EXPLANATION
E = f x ℎ  66.3 x 1.66 x 10-19 = f x 6.63 x 10-34  f = 1.6 x 1016 Hz

QUESTION: Which one of the following is irreversible?
A. Slow compression of an elastic spring
B. slow evaporation of a substance in an isolated vessel
C. Slow compression of a gas
D. a chemical explosion
EXPLANATION
Evaporation and compressions are physical properties which are reversible however a chemical explosion is irreversible so D.

QUESTION: Sensitivity of galvanometer is defined as
A. The deflection produced per unit microampere current
B. The deflection per force
C. force per unit area
D. none of them
EXPLANATION
The current sensitivity of a galvanometer is defined as the deflection produced when unit current passes through the galvanometer so the correct answer is D.

QUESTION: Consider a car is travelling for one hour. Whuch of the following trips have the same average velocity?
A. car travels 20 km due east and car travels 70 km due west.
EXPLANATION
Trip A displacement: 40 Km east then 20 km west, in vector form we can say that the car travels +40 then -20. So total displacement will be: +40-20=+20km Trip B displacement: 200 km east or +20 km so both are equal. When the displacements are equal and the time is also equal (1 hr), then the average velocity is also equal because  V=S/t

QUESTION: The angular speed of a particle, moving in a circle of radius 20 cm, increases from 2 rad/s to 40 rad/s in 9s. The ratio of its centripetal acceleration to tangential acceleration at the end of 19s is:
A. 400:1
B. 14:20
C. 800:1
D. 7:40
EXPLANATION
Cent. acc= ω^2xr ω(at 19 seconds)^2 x r(in meters) = 40^2 x 0.2 = 320 Tang. acc= r x Δω/Δt 0.2 x (40-2)/19 = 0.4 Cent acc/tang acc= 320/0.4= 800:1 option C.

QUESTION: What will be the De-Broglie wavelength when the kinetic energy of the electron increases by 5 times?
A. √5
B. 5
C. 1/√5
D. 1/5
EXPLANATION
λ2/λ1 = √E1/√E2 = √1/√5 = 1/√5

QUESTION: A sample of F-18 is used internally as a medical diagnostic tool to look for the effect of the positron decay (T1/2 = 110 min), how long does it take for 995 of the F-18 to decay?
A. 10.2 h
B. 11.2 h
C. 14.2 h
D. 12.2 h
EXPLANATION
N=No x e ^-λt N/No= 1% = 1/100 λ= ln2/T 1/100= e^ ln2/110 x t 100=2^t/110 ln100=t/100 x ln2 ln100/ln2 x 100 = t t= 12.2 h

QUESTION: A bullet of mass 10g leaves a rifle at an initial velocity 1000 m/s and strikes earth at the same level with a velocity of 500 m/s. The work in overcoming the resistance of air will be:
A. 500 J
B. 5000 J
C. 3750 J
D. 475 J
EXPLANATION
Work = energy KE=½ x 10 x (1000)^2 - ½ x 10 x (500)^2 5000-1250= 3750 J.

QUESTION: A cable 4km long and of total resistance 1 ohm carries electric current from a generator producing 100kW at 10,000 Volts. The current in amperes in the cable is:
A. 10
B. 10 000
C. 1000
D. 100 000
EXPLANATION
P=VI 100 000 = 10 000 X I I = 10 A so this is option A

QUESTION: 100 W heater is used to melt 50g of ice at 0oC. How long should the heater be switched on? Specific latent heat of fusion of ice is 334 J/g.
A. 28 min
B. 16.7 min
C. 2.8 min
D. 167 min
EXPLANATION
Q=ml ; 334 x 50 = 16.5k J power=energy/time 100=16500/t t= 165s /60 = 2.8 minutes.

QUESTION: The length and radius of an electric resistance of a certain wire are doubled simultaneously, then the:
A. Resistance will be doubled and specific resistance will be halved
EXPLANATION
R= ρ L/A Ρ is a constant so it wont change. l/r^2= 2L/(2r)^2 2L/4r^2 ½ resistance and specific resistance will remain unchanged so B.

QUESTION: The energy input to an engine is 60J, and the wiork it performs is 15J. What is its thermal efficiency?
A. 4.00
B. 1.00
C. 0.25
D. impossible to determine
EXPLANATION
The formula of efficiency is: = output/input = 15/60 = 0.25

QUESTION: Oil droplets of mass m and charge q are dropped between two horizontal parallel plates. Air resistance is negligible. The droplets are falling at constant velocity when electric field strength between the plates is E. Which of the following is true?
A. E-0
B. E < mg/q
C. E = mg/q
D. E > mg/q
EXPLANATION
When the oil drop (with charge –q) is in static equilibrium, the electric force it feels, qE upward, is balanced by the gravitational force, mg downward. Thus, qE = mg, so E = mg / q.

QUESTION: Wavelength of sound in air is 10 cm, what is the frequency of the sound wave?
A. 33 Hz
B. 330 Hz
C. 3300 Hz
D. 33000 Hz
EXPLANATION
V=λf Speed of sound=330m/s=0.1 x f 330/0.1 = 3300 Hz

QUESTION: Which colour of heat shows highest temperature?
A. red
B. blue
C. black
D. orange
EXPLANATION
Black absorbs heat so it will show the highest temperature.

QUESTION: A full wave rectifier uses load resistor of 1500 ohm. Assume the diodes have Rf = 10 ohm, Rr = infinity. The voltage applied to diode is 30V with a frequency of 50Hz. calculate AC power input.
A. 358.98 mW
B. 275.2 mW
C. 145.76 mW
D. 456.78 mW
EXPLANATION
The AC P(in)=Irms^2(RF+Rr). Irms=Vm/(Rf+RL)√2 =30/(1500+10) x 1.414 =13.5mA So, P(in)=(13.5 x 10^-3)^2 x (1500+10)=275.2mW.

QUESTION: 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, course 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: The hotel is two blocks east of the drugstore. The market is one block west of the hotel. The drugstore is west of the market. If the first two statements are true, the third statement is
A. True
B. False
C. maybe
D. unresolved
EXPLANATION
The market is one block west of the hotel. The drugstore is two blocks west of the hotel, so the drugstore is west of the market.

QUESTION: Number series: Choose which one is the different number from the following
A. 125
B. 131
C. 130
D. 138
EXPLANATION
131 is a prime number, the other three are composite numbers.

QUESTION: Which one of the following is a different one?
A. Skin
B. Lungs
C. Heart
D. Life
EXPLANATION
skin, lungs and heart are all organs inside the body. Life is the existence of an individual human being or animal hence out of the four it is different/the odd one out.

QUESTION: Statement: A large number of people living in the low-lying areas has been evacuated during the last few days to safer places. The government has rushed in relief supplies to the people living in the affected areas.
A. Statement I is the cause and statement II is its effect.
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 some common cause.
EXPLANATION
Evacuation of people from low-lying areas and providing relief measures is indicating the fact that some natural calamity had occurred like flood or so. Thus, both are the effects of that natural calamity.

QUESTION: Epicentre is related to
A. Cyclone
B. Volcano
C. Earthquake
D. Both A and B
EXPLANATION
The epicentre is the point on the surface of the Earth directly above the hypocenter/focus of an earthquake. It is the point in the crust where a seismic rupture begins.

QUESTION: Verbal reasoning Statements  (I) There is a sharp decline in the production of oilseeds this year.  (II) The Government has decided to increase the import quantum of edible oil.
A. Statement I is the cause and II is its effect
B. Statement II is the cause and I is its effect
C. Both statements are of independent causes
D. Both statements are the effects of the independent causes
EXPLANATION
Due to the decline, the oil supply was reduced and the only way to make up for the shortage of oil was to import it.

QUESTION: Verbal classification Who is the father of Computer?
A. Alan Turing
B. Charles Babbage
C. Simur Cray
D. Both A and B
EXPLANATION
Charles Babbage (26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor, and mechanical engineer, Babbage originated the concept of a digital programmable computer. Babbage is considered by some to be the father of the computer.

QUESTION: Dependent causes/ Independent causes: I. Punjab Board has announced the results of class 12. II. A candidate committed suicide after checking his results in class 12.
A. Statement I is the cause and statement II is its effect.
EXPLANATION
The candidate was probably extremely unhappy with his result when the board announced it and because of that, he committed suicide.

QUESTION: Verbal reasoning  Which country has the most news channels?
A. Russia
B. India
C. Australia
D. Brazil
EXPLANATION
Russia has 3,300 news channels. India has 392, brazil has 384 and Australia has 104.