NUMS 2026 paper with answer key and explanations (all 150 MCQs)

Answer: B. gp 41

HIV first attaches to a CD4 cell through gp120.

After attachment, gp41 draws the viral envelope and cell membrane together.

Their fusion opens the way for the viral contents to enter the host cell.

The fusion protein asked for here is gp41.

Answer: B. Reverse transcriptase

Complementary DNA is made by reading an RNA template.

Reverse transcriptase carries out this RNA-to-DNA conversion.

Integrase inserts viral DNA, while protease processes viral proteins.

The required enzyme is reverse transcriptase.

Answer: A. Small pox

Jenner collected material from cowpox lesions on a milkmaid's hand.

He used it to protect a boy against the related but more dangerous smallpox virus.

Exposure to cowpox antigens prepared the immune system to recognize smallpox.

The disease named in the question is smallpox.

Answer: B. Polyhedral capsid

Adenoviruses have an icosahedral capsid.

An icosahedron is a many-sided structure, so it is classified as polyhedral.

Adenoviruses are not helical and generally do not possess a lipid envelope.

Polyhedral capsid is the accurate description.

Answer: A. 2 ATPs

During strenuous exercise, oxygen delivery may not satisfy the muscles' demand.

The cells then rely more heavily on anaerobic glycolysis.

Four ATP are formed, but two are used during the early steps.

The net gain is 2 ATP per glucose molecule.

Answer: A. ATP and NADPH

Non-cyclic electron flow uses both photosystem II and photosystem I.

Electron movement builds the proton gradient needed to produce ATP.

The final electrons reduce NADP⁺ to NADPH, while water splitting also releases oxygen.

Among the listed pairs, ATP and NADPH are the products.

Answer: A. Decarboxylation

Pyruvic acid contains three carbon atoms.

During alcoholic fermentation, it first loses one carbon as CO₂.

Removal of carbon dioxide is called decarboxylation and leaves two-carbon acetaldehyde.

Acetaldehyde is then reduced to ethanol in the next step.

Answer: B. Coenzyme Q → cytochrome b → cytochrome c → cytochrome a → cytochrome a

Coenzyme Q receives electrons and passes them into the cytochrome chain.

The simplified sequence proceeds through cytochromes b, c, a and a₃.

Oxygen accepts the electrons at the end of the pathway.

The sequence beginning with coenzyme Q followed by b, c, a and a₃ is correct.

Answer: B. Matrix of mitochondria and mitochondrial intermembrane space

Respiratory electron carriers are embedded in the inner mitochondrial membrane.

As electrons move along the chain, H⁺ ions are pumped out of the matrix.

They accumulate in the intermembrane space and create a proton gradient.

The movement asked for is from the matrix to the intermembrane space.

Answer: C. 4CO₂, 2ATP, 6NADH, 2FADH₂

One glucose molecule supplies two acetyl-CoA molecules, so the Krebs cycle turns twice.

Those two turns release 4CO₂ and produce 6NADH.

They also form 2FADH₂ and 2 ATP equivalents.

The complete set is 4CO₂, 2ATP, 6NADH and 2FADH₂.

Answer: D. Inner mitochondrial membrane

The mitochondrial electron-transport chain lies in the inner membrane.

Its carrier proteins and ATP synthase are arranged along the cristae.

Folding of this membrane provides a large surface for oxidative phosphorylation.

The inner mitochondrial membrane is therefore the correct location.

Answer: D. Fructose

A monosaccharide contains one sugar unit.

Fructose is a single-unit sugar.

Sucrose, maltose and lactose each contain two linked monosaccharides.

Only fructose belongs to the monosaccharide group.

Answer: C. 85%

Brain tissue contains a particularly high proportion of water.

The approximate textbook value used for brain cells is 85 percent.

This water provides the medium for reactions and movement of dissolved substances.

The expected percentage is 85%.

Answer: B. 3%, 4%

The question asks for the representative carbohydrate content of two cell types.

Bacterial cells are given as containing about 3 percent carbohydrate.

Mammalian cells are represented by the slightly higher value of 4 percent.

The matching pair is 3% and 4%.

Answer: B. Hydrogen bonding

Water molecules form many hydrogen bonds with one another.

Added heat is first used partly to loosen these attractions.

As a result, considerable energy produces only a small rise in temperature.

Hydrogen bonding accounts for water's high heat capacity.

Answer: A. Protein

Haemoglobin carries oxygen in red blood cells.

Haemoglobin is a protein containing iron-bearing haem groups.

Oxygen binds reversibly to these groups in the lungs and is released in tissues.

The biomolecule involved in this transport is protein.

Answer: D. Chitin

Cellulose is generally described as the most abundant natural organic polymer.

Chitin is also widespread in arthropod exoskeletons and fungal cell walls.

Its extensive occurrence places it next to cellulose in abundance.

The second most abundant option is chitin.

Answer: C. Acyl glycerol

Glycerol has three hydroxyl groups available for reaction.

Fatty acids join these groups through ester bonds.

The products are acylglycerols, including triglycerides when all three sites react.

Acyl glycerol is the suitable answer.

Answer: C. Lack of middle lamella

The middle lamella contains pectic material that cements neighboring plant cells.

Calcium and magnesium help stabilize these pectates.

A magnesium shortage therefore interferes most directly with formation of this cementing layer.

The affected structure is the middle lamella.

Answer: C. Mitochondria - deamination

Mitochondria are primarily responsible for aerobic respiration and ATP formation.

The endoplasmic reticulum participates in processes such as detoxification.

Lysosomes digest damaged organelles during autophagy.

Mitochondria paired with deamination is the mismatched association.

Answer: A. Mitochondria

Athletic training raises the muscles' demand for sustained aerobic energy.

Muscle cells adapt by producing more mitochondria.

The additional mitochondria increase the capacity for oxidative ATP production.

Mitochondria are the organelles expected to increase.

Answer: C. RER SER golgi complex

Secretory proteins begin on ribosomes attached to rough ER.

They pass through transitional or smooth ER regions into transport vesicles.

The vesicles then carry them to the Golgi complex for processing and sorting.

The intended pathway is RER, SER and Golgi complex.

Answer: A. 16

Ordinary onion somatic cells are diploid.

The diploid chromosome number of Allium cepa is 16.

Only its gametes would carry the reduced haploid number of 8.

The chromosome number requested is 16.

Answer: B. Protein modification

The Golgi apparatus receives proteins made in the endoplasmic reticulum.

It modifies those proteins and sorts them according to their destinations.

A toxin that damages the Golgi will therefore disturb normal protein processing.

Protein modification is the function most directly affected.

Answer: A. Golgi apparatus

Products arriving from the ER enter the Golgi apparatus.

Golgi cisternae modify and sort this material.

The material is then packed into vesicles for secretion or delivery inside the cell.

Modification and packaging occur in the Golgi apparatus.

Answer: D. Hypothalamus

The hypothalamus monitors the concentration of body fluids.

It regulates thirst and helps control the release of ADH.

These responses coordinate water intake with kidney water conservation.

Damage to the hypothalamus can therefore cause persistent water imbalance.

Answer: B. Medulla

Strenuous exercise produces extra CO₂ and increases acidity in the blood.

Respiratory centers in the medulla detect this change.

They increase breathing rate and depth so that more CO₂ is exhaled.

The brain region involved is the medulla.

Answer: B. Arachnoid mater & Pia mater

Cerebrospinal fluid surrounds the brain and spinal cord.

Outside the brain, it occupies the subarachnoid space.

That space lies between the arachnoid mater and the pia mater.

Arachnoid mater and pia mater form the correct pair.

Answer: A. Promotes protein synthesis

Growth hormone remains active after a person stops growing taller.

It promotes amino-acid uptake and supports protein synthesis.

These effects help maintain and repair adult tissues.

Promotion of protein synthesis is its relevant adult role.

Answer: B. Inhibits Ca²⁺ absorption by intestine

Calcitonin is released when blood calcium is high.

It lowers blood calcium mainly by reducing osteoclast activity.

It can also limit calcium entry from the intestine.

Inhibition of intestinal Ca²⁺ absorption is the matching option.

Answer: B. Glucagon

A fall in blood glucose is detected by pancreatic alpha cells.

These cells release glucagon.

Glucagon stimulates the liver to break down glycogen and release glucose.

The hormone secreted in this situation is glucagon.

Answer: A. Interneuron synapse dendrites cell body of motor neuron

A reflex signal passes from a sensory pathway to an interneuron.

The interneuron communicates with a motor neuron across a synapse.

The impulse enters the motor neuron's dendrites and cell body before traveling along its axon.

The first sequence reflects this route most closely.

Answer: B. Spiny ant eater

The spiny anteater, or echidna, is a monotreme mammal.

It has hair and produces milk, which are mammalian traits.

It also lays eggs, a feature traditionally associated with reptiles.

The animal combining both sets of features is the spiny anteater.

Answer: B. Holoenzyme

Apoenzyme is the inactive protein part of an enzyme and cannot function alone. When the required cofactor binds to the apoenzyme, the complete and catalytically active enzyme formed is called a holoenzyme.

Apoenzyme + Cofactor = Holoenzyme

So, because the question asks about the enzyme after it becomes active with the help of a cofactor, the best answer is Holoenzyme.

Answer: B. Compete with substrate for active site

A competitive inhibitor occupies the enzyme\'s active site.

It competes directly with the substrate for access to that site.

Raising substrate concentration can reduce the inhibitor\'s effect.

Competition for the active site is the defining description.

Answer: A. Hemotoxic

Hemotoxic venom → acts on the heart and cardiovascular system

Neurotoxic venom → acts on the nervous system and brain

Cytotoxic venom → localized action at the bite site

Answer: C. Urease

Absolute specificity means that an enzyme acts on one particular substrate.

Urease catalyzes the hydrolysis of urea.

Its action is much narrower than enzymes that accept several related substrates.

Urease is the standard example of absolute specificity.

Answer: B. More acidic

Industrial pollutants can add acidic substances to aquatic systems.

More hydrogen ions lower the pH of the water.

The resulting acidic conditions can alter enzyme ionization and disrupt plant metabolism.

The affected water becomes more acidic.

Answer: A. Stamen, carpel, sepals, petals

Stamens, carpels, sepals and petals are the main floral organs.

Their comparable origin and arrangement across flowering plants allow homologous comparison.

Thalamus and stalk are supporting structures rather than the complete basic organ set being tested.

The first group lists the required homologous floral structures.

Answer: D. Physical, Ecological or Environmental

Species distribution can be restricted by several kinds of barriers.

Mountains and oceans act as physical barriers.

Temperature, water and ecological requirements can also prevent survival or dispersal.

Physical, ecological or environmental barriers cover the full range.

Answer: C. They are present on both X and Y

Pseudoautosomal genes occupy matching regions of the X and Y chromosomes.

Those regions can pair and exchange material during meiosis.

Their inheritance can therefore resemble that of autosomal genes.

They are described as being present on both X and Y.

Answer: A. Increase in favorable alleles

A natural disaster creates strong selection pressure.

Individuals with helpful inherited traits are more likely to survive and reproduce.

Their alleles appear more frequently in the next generations.

The outcome is an increase in favorable alleles.

Answer: A. Connective tissues Smooth muscle Elastic tissue Endothelium

The outer layer of an artery is connective tissue.

Moving inward, the wall contains smooth muscle and elastic tissue.

The lumen is lined by a smooth endothelial layer.

The first sequence follows this outside-to-inside arrangement.

Answer: B. Tightly packed cells

The epidermis forms the body's outer protective covering.

Its epithelial cells are closely arranged rather than scattered.

This compact organization limits water loss and blocks physical and biological hazards.

Tightly packed cells correctly describe the epidermis.

Answer: B. Smooth muscles

Smooth muscle occurs in the walls of hollow organs.

Its contractions are involuntary and move material through structures such as the intestine.

Cardiac muscle is confined to the heart, while skeletal muscle moves bones.

The tissue controlling movement through hollow organs is smooth muscle.

Answer: C. Sarcomere

Myofibrils are divided into repeating contractile sections.

Each section extends from one Z line to the next.

Actin and myosin slide within this region during contraction.

This smallest functional unit is the sarcomere.

Answer: B. Ca²⁺ ions

Calcium ions bind to troponin when a muscle fibre is stimulated.

Troponin changes shape and moves tropomyosin away from actin's binding sites.

Myosin heads can then attach to actin and form cross-bridges.

Ca²⁺ is the ion that initiates this sequence.

Answer: C. I band shorten H-zone disappears

Thin filaments slide farther over thick filaments during contraction.

The I band becomes shorter as overlap increases.

The H zone also narrows and may disappear, while the A band remains unchanged.

Shortening of the I band with disappearance of the H zone is correct.

Answer: C. Rhizobium

Rhizobium lives in association with the roots of legumes.

Its nitrogenase enzyme reduces atmospheric N₂ to ammonia.

The ammonia can then form ammonium and enter organic nitrogen compounds.

Rhizobium performs the conversion asked for here.

Answer: A. Nitrofurans

Chemotherapeutic agents act inside the body against disease-causing organisms.

Nitrofurans include antibacterial drugs used against susceptible bacteria.

Hydrogen peroxide and hypochlorite are mainly disinfectants, while potassium sorbate is a preservative.

Nitrofurans are the antibacterial chemotherapeutic agents.

Answer: C. They need a temperature 2°C lower than human body temperature

Sperm production requires a temperature slightly below core body temperature.

The scrotum keeps the testes outside the abdominal cavity for this reason.

Their temperature is maintained at roughly 2°C below the body's internal temperature.

The third statement describes the required condition.

Answer: D. Corpus luteum degenerate, LH decline, progesterone decline

Without fertilization, no pregnancy signal maintains the corpus luteum.

The corpus luteum degenerates and progesterone secretion falls.

LH support also declines as the cycle moves toward menstruation.

Decline of both LH and progesterone matches the expected events.

Answer: D. Red blood cells → capillaries → alveoli

Near the lungs, bicarbonate returns from plasma into red blood cells.

It is converted back into CO₂ inside those cells.

CO₂ then crosses the pulmonary capillaries and enters the alveoli for exhalation.

The order is red blood cells, capillaries and alveoli.

Answer: C. Pepsin, trypsin, erepsin

Pepsin begins protein digestion in the stomach.

Trypsin continues peptide breakdown in the small intestine.

Intestinal peptidases, traditionally grouped as erepsin, complete the process.

Pepsin, trypsin and erepsin form the correct enzyme set.

Answer: D. Epistatic gene

Epistasis occurs when a gene at one locus masks a gene at another locus.

The masking gene is called epistatic.

The gene whose expression is suppressed is called hypostatic.

The description in the question refers to an epistatic gene.

Answer: B. 6.02 × 10²³ ions

The notation Na⁺ refers specifically to sodium ions.

One mole contains Avogadro\'s number of the stated particles.

Avogadro\'s number is 6.02 × 10²³.

One mole of Na⁺ therefore contains 6.02 × 10²³ ions.

Answer: C. Number of protons

Positive rays are made of positive ions formed from the gas in the discharge tube.

Changing the gas changes the identity and mass of those ions.

The proton number is the listed property that changes from one element to another.

That change affects the charge-to-mass ratio measured for the positive rays.

Answer: A. 4s < 3d < 4p < 5s

Using the (n + l) rule:

4s: 4 + 0 = 4

3d: 3 + 2 = 5

4p: 4 + 1 = 5

5s: 5 + 0 = 5

When (n + l) is the same, the orbital with lower n has lower energy.

Answer: D. P₁V₁ = P₂V₂

Boyle's law applies to a fixed amount of gas at constant temperature.

Pressure rises when volume falls, so the two quantities are inversely related.

Their product remains constant between any two states.

The correct expression is P₁V₁ = P₂V₂.

Answer: C. −273.15°C

Zero kelvin is the lowest point on the thermodynamic temperature scale.

To convert it to Celsius, subtract 273.15 from the kelvin value.

The calculation gives 0 − 273.15 = −273.15°C.

The negative Celsius value in option C is correct.

Answer: D. Low external pressure

Water boils when its vapour pressure equals the surrounding pressure.

Atmospheric pressure is lower at the Murree hills than at sea level.

Water therefore boils at a lower temperature and is less hot while boiling.

The egg takes longer because the external pressure is lower.

Answer: C. High polarizability

Iodine has a much larger electron cloud than fluorine.

Its cloud is easier to distort, so iodine molecules develop stronger London forces.

Those attractions raise iodine's melting and boiling points.

High polarizability explains why iodine is solid while fluorine is gaseous.

Answer: C. Ions can only vibrate about their fixed

The ions in an ionic solid are locked into a crystal lattice.

They can vibrate about fixed positions but cannot travel through the solid.

Without mobile charged particles, electrical conduction is poor.

The restriction to vibration is the relevant reason.

Answer: A. Octahedral

A crystal's external shape depends on the relative growth of its faces.

Urea changes the growth pattern of sodium chloride crystals.

The modified crystal habit becomes octahedral even though the internal lattice remains ionic.

Octahedral is the expected shape.

Answer: D. 0

For gaseous equilibria, Kp = Kc(RT)^Δn.

Here, Δn is the difference between gaseous product and reactant moles.

If Δn is zero, the factor (RT)^0 becomes one.

Kp and Kc are equal when n equals zero.

Answer: D. 7.35

Human arterial blood is maintained within a narrow, slightly alkaline range.

The lower end of the normal range is about 7.35.

Buffers, breathing and kidney function work together to keep the pH stable.

The matching value is 7.35.

Answer: D. Zero-order reaction

A zero-order rate does not contain a concentration term.

Its rate law is simply rate = k.

The rate constant therefore carries the same units as reaction rate.

This equality of units identifies a zero-order reaction.

Answer: B. k = Ae^(−Eₐ/RT)

The Arrhenius equation describes how temperature and activation energy affect k.

Its standard form is k = Ae^(−Eₐ/RT).

The negative exponent shows that a larger activation barrier lowers the rate constant.

The expression in option B is the complete equation.

Answer: A. ΔH_cycle = 0

Hess's law works because enthalpy is a state function.

Only the initial and final states determine the overall enthalpy change.

A complete cycle returns to its starting state.

The sum of ΔH around that cycle must be zero.

Answer: B. ΔU = q + w

The first law tracks heat and work entering or leaving a system.

With the chemistry sign convention, work done on the system is positive.

Internal energy therefore changes according to ΔU = q + w.

The expression containing q and w is correct.

Answer: B. 2e⁻ and 2H⁺

Begin with HSO₃⁻ + H₂O → HSO₄⁻.

The oxygen atoms are already balanced after adding water on the left.

Place 2H⁺ and 2e⁻ on the product side to balance hydrogen and charge.

The completed oxidation half-equation uses the terms in option B.

Answer: C. +7

Let the oxidation state of manganese in KMnO₄ be x.

Potassium contributes +1, while four oxygen atoms contribute −8.

For a neutral compound, +1 + x − 8 = 0.

Solving the equation gives manganese an oxidation state of +7.

Answer: A. Decrease in energy

Separated atoms have more potential energy than atoms in a stable bond.

As the atoms approach, attractive forces lower the system's energy.

At the equilibrium distance, attraction and repulsion balance.

Bond formation therefore produces a decrease in energy.

Answer: C. One σ and one π bond

The two oxygen atoms in O₂ are joined by a double bond.

A double bond contains one head-on σ bond.

It also contains one sideways π bond.

O₂ therefore has one σ bond and one π bond.

Answer: B. F > Cl > Br

Ionization energy falls as atomic size and shielding increase down the halogen group.

Fluorine holds its outer electrons more strongly than chlorine.

Chlorine in turn holds them more strongly than bromine.

The decreasing order is F > Cl > Br.

Answer: B. Inter-electronic repulsion

Argon\'s outermost shell is completely filled (a full octet), so inter-electronic repulsion among those valence electrons is at its maximum, offsetting the extra nuclear charge and making Ar\'s atomic size come out larger than Cl\'s despite sitting one place further right in the same period. Ar\'s ionization energy genuinely is higher than Cl\'s, but that\'s a separate consequence of the same full shell, not the reason for the size increase.

Answer: D. K

A substance is lighter than water when its density is below 1 g cm⁻³.

Potassium has a density lower than this value.

Caesium, rubidium and iron are denser than water.

Potassium is the element that meets the condition.

Answer: A. Metallic bond strength

Moving down Group IA or IIA adds another electron shell.

The larger atoms hold their outer electrons less strongly.

Metallic bonding consequently becomes weaker down these groups.

Metallic bond strength is the quantity that decreases.

Answer: C. Ba < Sr < Ca < Mg < Be

Electronegativity decreases down Group IIA.

Beryllium is the most electronegative member listed, while barium is the least.

Arranging the elements from lower to higher electronegativity reverses the usual downward order.

The sequence is Ba < Sr < Ca < Mg < Be.

Answer: A. Pyrrole

A heteroatom is an atom other than carbon within an organic ring.

Pyrrole contains one nitrogen atom in its five-membered ring.

Naphthalene, anthracene and cyclohexene contain carbon rings without a heteroatom.

Pyrrole is the only matching compound.

Answer: C. –C(=O)–NH₂

An acid amide contains a carbonyl carbon directly bonded to nitrogen.

For a primary amide, the nitrogen group is –NH₂.

The complete functional group is –C(=O)–NH₂.

The structure shown in option C represents an amide.

Answer: C. Alkene

Concentrated sulfuric acid removes water from an alcohol at about 170°C.

Hydrogen leaves one carbon and the hydroxyl group leaves the neighboring carbon.

The two carbons then form a double bond.

This dehydration produces an alkene.

Answer: A. Hex-2-ene

The longest chain in the displayed formula contains six carbon atoms.

Numbering begins from the end nearest the double bond.

The double bond starts at carbon 2.

The correct IUPAC name is hex-2-ene.

Answer: D. Addition reactions

An alkene contains a carbon-carbon double bond with a relatively reactive π component.

Reagents commonly add across this double bond.

The π bond is replaced by two new σ bonds during the reaction.

Addition reactions are therefore characteristic of alkenes.

Answer: A. 400°C and 1000 atm

Ethene forms polyethene by addition polymerization.

Its double bonds open and link many ethene molecules into a long chain.

The process requires high pressure and elevated temperature.

Among the listed conditions, 400°C and 1000 atm is the intended pair.

Answer: D. R–I > R–Br > R–Cl > R–F

Nucleophilic substitution becomes easier as the carbon-halogen bond weakens.

The C–I bond breaks most readily, followed by C–Br and C–Cl.

The C–F bond is strongest and fluoride is the poorest leaving group.

The reactivity order is R–I > R–Br > R–Cl > R–F.

Answer: C. Tertiary alcohol

In (CH₃)₃C–OH, the carbon carrying the hydroxyl group is bonded to three carbon groups.

An alcohol with this arrangement is tertiary.

The compound is specifically 2-methylpropan-2-ol.

Tertiary alcohol is the correct classification.

Answer: D. Phenol

Phenol reacts with formaldehyde to form phenol-formaldehyde resins.

Further cross-linking produces a hard plastic such as Bakelite.

Methanol, ethanol and propanol do not form this familiar phenolic resin.

Phenol is used in the stated plastic manufacture.

Answer: B. Propanone

The question follows the strong-oxidation convention used in the paper.

Under that convention, propanone is cleaved into a two-carbon acid and a one-carbon acid.

The one-carbon product is methanoic acid, also known as formic acid.

Propanone is therefore the intended answer.

Answer: B. 2-Ethyl-3-methyl pentanal

The aldehyde carbon must be carbon 1 of the parent chain.

The longest suitable chain contains five carbons, giving pentanal.

An ethyl group lies at carbon 2 and a methyl group at carbon 3.

Alphabetical order gives 2-ethyl-3-methylpentanal.

Answer: C. Phthalic acid

The compound contains two –COOH groups on adjacent carbons of a benzene ring.

Its systematic description is benzene-1,2-dicarboxylic acid.

This ortho dicarboxylic acid has the common name phthalic acid.

Phthalic acid is the correct option.

Answer: B. P₂O₅

An acid anhydride forms when water is removed from two carboxylic acid molecules.

Phosphorus pentoxide is a strong dehydrating agent.

It removes water from two molecules of acetic acid and allows the anhydride bond to form.

The required reagent is P₂O₅.

Answer: C. H₂

The hydrogen in a carboxyl group can be displaced by a reactive metal.

For sodium, the reaction is 2RCOOH + 2Na → 2RCOONa + H₂.

The salt formed is sodium carboxylate.

The gas evolved is hydrogen.

Answer: A. Myosin

Myosin is a motor protein found in muscle fibres.

It binds to actin and uses ATP during cross-bridge cycling.

Repeated attachment and movement of myosin produce contraction.

ATP-dependent detachment also allows the muscle to relax.

Answer: C. Salt bridges

Haemoglobin contains several polypeptide subunits.

Salt bridges between charged side chains help hold those subunits in their quaternary arrangement.

Peptide bonds hold amino acids within each individual chain.

Salt bridges are the interaction asked for between the chains.

Answer: C. 76°

For a projectile, maximum height is H = u²sin²θ/(2g).

Its horizontal range is R = u²sin2θ/g.

Equating H and R gives tanθ = 4.

The corresponding angle is approximately 76°.

Answer: B. 45°

Projectile range is R = u²sin2θ/g for a fixed launch speed.

The range is greatest when sin2θ reaches its maximum value of 1.

This happens at 2θ = 90°.

The required projection angle is therefore 45°.

Answer: C. The earth possesses more inertia

The ball and Earth exert equal gravitational forces on each other.

Earth has an enormously greater mass and therefore far greater inertia.

Its acceleration is negligible, while the ball accelerates downward.

The ball returns because Earth possesses much more inertia.

Answer: C. Momentum

An explosion produces internal forces between the fragments.

If external impulse is negligible, those internal forces cannot change total momentum.

Stored energy may become kinetic energy, so kinetic energy need not remain constant.

The conserved quantity is momentum.

Answer: D. 180°

Work done by a constant force is W = Fs cosθ.

Work becomes negative when the force has a component opposite the displacement.

At 180°, cosθ = −1 and the two directions are exactly opposite.

The angle producing negative work is 180°.

Answer: D. Four times

Kinetic energy is K = ½mv².

The mass remains fixed while the speed changes from v to 2v.

Squaring the new speed gives (2v)² = 4v².

The kinetic energy becomes four times its original value.

Answer: D. 90%

Efficiency compares useful electrical energy with the chemical energy supplied by the cell.

Some energy is always lost inside a real battery.

The value used for the dry cell in this question is 90 percent.

The expected answer is therefore 90%.

Answer: C. Less negative

Taking gravitational potential energy as zero at infinity gives U = −GMm/r.

Increasing r reduces the magnitude of the negative fraction.

The value moves upward toward zero.

Gravitational potential energy therefore becomes less negative.

Answer: B. 10.8MJ

One kilowatt-hour equals 1000 W multiplied by 3600 s.

This is 3.6 × 10⁶ J, or 3.6 MJ.

Three kilowatt-hours contain 3 × 3.6 MJ.

The energy is 10.8 MJ.

Answer: B. Large speed and small radii

Ideal banking follows tanθ = v²/(rg).

A higher speed increases the value on the right and requires a steeper bank.

A smaller curve radius has the same effect.

Large speed with small radius gives the steepest requirement among the choices.

Answer: D. Net torque

Angular acceleration requires a turning effect on the body.

That turning effect is torque.

The rotational equation τ_net = Iα links net torque directly with angular acceleration.

Net torque is the correct cause.

Answer: B. Torque

Force changes translational motion according to F = ma.

Torque changes rotational motion according to τ = Iα.

The two quantities play corresponding roles in linear and angular mechanics.

Torque is the rotational analogue of force.

Answer: B. π/180 radians

One complete revolution is 360°.

The same revolution measures 2π radians.

Dividing 2π by 360 gives the radian value of one degree.

Thus, 1° = π/180 radians.

Answer: A. π/2

In uniform circular motion, velocity is tangent to the circular path.

Centripetal acceleration points along the radius toward the centre.

A tangent is perpendicular to the radius at the point of contact.

The angle between velocity and acceleration is π/2.

Answer: B. λ/2

A stationary wave has alternating nodes and antinodes.

Two neighboring nodes are separated by half of a complete wavelength.

A node and its nearest antinode are only one-quarter wavelength apart.

The node-to-node distance is λ/2.

Answer: B. Frequency

The source fixes the frequency of a wave.

When the wave enters water, its speed changes because the medium changes.

Its wavelength adjusts through v = fλ, but the source frequency stays the same.

Frequency is the quantity that does not change.

Answer: A. Blue shift

Light from an approaching star is compressed to shorter observed wavelengths.

Shorter wavelength corresponds to higher frequency.

This Doppler change shifts spectral lines toward the blue end of the spectrum.

The approaching star shows a blue shift.

Answer: C. Quadrupled

For a wave in the same medium, intensity is proportional to amplitude squared.

Doubling amplitude changes A² into (2A)².

The new value is 4A².

The intensity therefore becomes four times greater.

Answer: B. Metabolism

The first law of thermodynamics expresses conservation of energy.

Metabolism converts chemical energy from food into work, stored energy and heat.

The total energy is redistributed rather than created or destroyed.

Metabolism is the matching example.

Answer: C. Increase in temperature & kinetic energy

Shaking the flask means mechanical work is done on the tea.

A thermos limits heat exchange with the surroundings.

The work is dissipated into internal energy, increasing molecular motion.

Both temperature and average kinetic energy rise.

Answer: B. Universal gas constant

For an ideal gas, Cp includes the energy needed for expansion work.

Cv does not include that work because volume remains fixed.

The difference between the two molar heat capacities is R.

R is the universal gas constant.

Answer: C. Stationary & point charges

Coulomb's law treats charges as stationary point sources.

Under these conditions, force depends on charge values and inverse square distance.

Extended or accelerating charge distributions require broader electromagnetic treatment.

Stationary point charges satisfy the stated law directly.

Answer: B. Direction of electric field

Electric field direction is defined as the force direction on a positive test charge.

For a positive charge, F = qE points along the field.

The resulting acceleration and initial motion follow that direction.

The charge moves in the direction of the electric field.

Answer: B. Constant

Half-life is a characteristic property of a particular radionuclide.

It does not depend on the initial amount of the sample.

Removing material changes the activity but not the decay probability of each nucleus.

The half-life remains constant for that radionuclide.

Answer: C. Second

Resistance is measured in ohms and capacitance in farads.

The product RC has units ΩF.

Using the electrical unit definitions, ΩF reduces to seconds.

RC is therefore a time quantity.

Answer: B. Resistance

The temperature coefficient describes fractional change per kelvin.

Here, the quantity changing with temperature is electrical resistance.

It is written as the change in resistance divided by the original resistance and temperature change.

The name required is temperature coefficient of resistance.

Answer: D. Conductor

An ohmic device obeys V = IR at a constant temperature.

Its resistance remains approximately constant as current changes.

A metallic conductor shows this behavior, unlike a thermistor or filament lamp.

Conductor is the ohmic example.

Answer: B. Negative temperature coefficient

A positive temperature rise is accompanied by a fall in resistance.

The ratio of resistance change to temperature change is therefore negative.

Materials showing this behavior are often described as NTC materials.

They have a negative temperature coefficient.

Answer: C. Magnetic flux density

Magnetic flux measures the total magnetic field passing through a surface.

Flux divided by perpendicular area gives magnetic flux density.

This quantity is represented by B and measured in tesla.

Field lines per unit area describe magnetic flux density.

Answer: D. Velocity, magnetic field & charge

The force on a moving charge is F = qvB sinθ.

Its magnitude depends on the charge q and speed v.

It also depends on magnetic-field strength B and the angle between v and B.

Velocity, magnetic field and charge form the matching set.

Answer: C. 90°

Magnetic force contains the angular factor sinθ.

The greatest possible value of sinθ is 1.

This occurs when the velocity is perpendicular to the field.

The force is maximum at 90°.

Answer: B. Dynamic e.m.f.

A generator creates emf by moving a conductor through a magnetic field.

The conductor cuts magnetic flux and charges experience magnetic force.

This motion-generated voltage is called dynamic emf.

Generator action is an application of dynamic emf.

Answer: A. Double

Faraday's law gives induced emf as ε = N|ΔΦ|/Δt.

If flux change and time remain fixed, emf is directly proportional to the number of turns.

Changing N to 2N therefore changes ε to 2ε.

The induced emf doubles.

Answer: B. Electric signals

A seismograph first detects mechanical movement of the ground.

Its electromagnetic sensor responds to that motion.

The sensor produces a voltage or current that can be recorded electronically.

Ground movement is converted into an electrical signal.

Answer: B. Four diodes

A bridge rectifier contains four diodes.

One pair conducts during the positive half-cycle.

The other pair conducts during the negative half-cycle while keeping load current in the same direction.

Four diodes are required for the bridge arrangement.

Answer: C. Diode

A diode conducts readily in one direction and blocks current in the other.

This one-way behavior is called rectification.

Rectification changes an alternating input into a pulsating direct output.

The component used for this purpose is a diode.

Answer: C. Zero mass, finite momentum

A photon has no rest mass.

It nevertheless carries energy E = hf.

Its momentum is p = h/λ, which is not zero.

A photon therefore has zero rest mass and finite momentum.

Answer: A. Photo electric effect

Photocells respond when light releases electrons from a material.

Solar cells also convert photon energy into electrical energy by exciting charge carriers.

Both devices rely on the interaction of photons with electrons.

The relevant principle is the photoelectric effect.

Answer: D. Alpha particle

The question does not state the condition required for a strict wavelength comparison.

Under the usual equal-speed assumption, de Broglie wavelength is λ = h/(mv).

Greater particle mass then gives a shorter wavelength.

The alpha particle is used as the conditional answer because it is the heaviest listed material particle.

Answer: C. Lyman series

Hydrogen spectral series differ according to their final energy level.

Lyman transitions end at n = 1 and have the largest energy gaps.

Larger photon energy means higher frequency and shorter wavelength.

The Lyman series has the smallest wavelengths.

Answer: C. Vagueness

Clarity means that an idea is easy to understand.

Vagueness describes language that is uncertain or unclear.

The two words express opposite meanings.

Vagueness is the antonym of clarity.

Answer: A. Expelled from the house

A tenant who is evicted is legally or forcibly removed from a property.

The word does not mean investigated, threatened or rewarded.

Yasir could not pay the rent, so removal from the house fits the context.

Evicted here means expelled from the house.

Answer: B. Has been crying

The phrase all morning describes an activity continuing over a period up to the present.

Present perfect continuous is used for this kind of unfinished action.

Its structure is has or have been followed by the –ing form.

With the singular subject baby, the correct form is has been crying.

Answer: C. Will have taken over

The phrase by 2040 sets a future completion point.

The job takeover will be complete before or at that future time.

Future perfect uses will have followed by the past participle.

Will have taken over is the required form.

Answer: B. Complex

Each time one of us touches the soil is a dependent time clause.

We feel a sense of personal renewal is the independent main clause.

One dependent clause joined to one independent clause forms a complex sentence.

The sentence is complex.

Answer: B. Milton, the great English poet, was blind

The words the great English poet rename Milton and add nonessential information.

This kind of phrase is a nonrestrictive appositive.

A comma is placed before and after such an appositive.

Milton, the great English poet, was blind is correctly punctuated.

Answer: C. A Sindhi woman is going through a bazaar with bare feet

A woman is singular, so it must be followed by is going.

Bare means uncovered and is the correct adjective for feet.

Women would require a plural verb, while bear has a different meaning.

A Sindhi woman is going through a bazaar with bare feet is correct.

Answer: A. Against

Caution follows the fixed expression cautioned against.

Against introduces the danger or person about whom the warning is given.

The remaining prepositions do not form the standard expression in this sentence.

The public are cautioned against pickpockets.

Answer: D. Affect / effect

Affect is normally a verb meaning to influence.

Effect is normally a noun meaning a result or consequence.

Lack of sleep can affect health and produce a bad effect on grades.

The correct pair is affect and effect.

Answer: D. Having finished his exercise, he put away his books.

Having finished his exercise must describe the person who performed that action.

Placing the books immediately after the phrase creates a dangling modifier.

The subject he correctly identifies the person who finished the exercise.

Having finished his exercise, he put away his books is the well-formed sentence.

Answer: B. He is certainly not a liar.

Anything but is an idiom that strongly rejects the description that follows.

Calling someone anything but a liar means the speaker does not consider him a liar.

It does not suggest partial dishonesty or poor character.

The sentence means that he is certainly not a liar.

Answer: D. Without apology you will be punished.

Unless introduces a negative condition and means if not.

The sentence can be rewritten as: If you do not apologise, I shall punish you.

Punishment depends on the absence of an apology.

Without an apology, the person will be punished.

Answer: D. Have his revenge

To pay off or settle old scores is an idiom.

It refers to taking revenge for an earlier wrong or disagreement.

The phrase is unrelated to examination marks or an ordinary financial debt.

He wants to have his revenge.

Answer: A. Deeply

Profoundly describes something done with great depth or seriousness.

Reflecting profoundly means thinking carefully about one's life.

Superficially and shallow express the opposite idea.

The bracketed word means deeply.

Answer: B. Did not take it seriously.

Taking advice with a pinch of salt means receiving it with doubt or reservation.

The listener does not accept the advice completely at face value.

It is different from following the advice happily or treating it as unquestionably correct.

Ali did not take the advice seriously.