NEET 2027 · Full Syllabus Practice · Aamirah Fathima
Answer Key & Solutions — Set 5
Quick-reference grid first, then a one-line reason for every question with its topic tag. Score the paper, then re-work every wrong answer before moving on.
Questions
180
Max marks
720
Correct
+4
Wrong
−1
Set
5
Quick key
All 180 answers
001 C
002 C
003 B
004 B
005 B
006 B
007 C
008 B
009 B
010 C
011 B
012 B
013 B
014 A
015 B
016 B
017 B
018 B
019 B
020 C
021 B
022 C
023 B
024 C
025 B
026 B
027 B
028 B
029 B
030 B
031 B
032 B
033 B
034 B
035 B
036 C
037 B
038 C
039 B
040 C
041 B
042 B
043 C
044 C
045 B
046 B
047 B
048 B
049 B
050 B
051 B
052 B
053 C
054 B
055 A
056 B
057 B
058 B
059 A
060 B
061 C
062 B
063 B
064 B
065 B
066 B
067 C
068 B
069 B
070 B
071 B
072 B
073 B
074 B
075 B
076 B
077 C
078 B
079 B
080 B
081 B
082 B
083 B
084 B
085 B
086 B
087 B
088 B
089 B
090 A
091 B
092 B
093 B
094 C
095 B
096 B
097 B
098 B
099 B
100 A
101 B
102 B
103 B
104 B
105 B
106 B
107 B
108 B
109 C
110 B
111 B
112 B
113 C
114 B
115 B
116 B
117 B
118 B
119 A
120 B
121 B
122 B
123 B
124 B
125 B
126 B
127 B
128 B
129 B
130 B
131 B
132 B
133 B
134 B
135 B
136 B
137 C
138 C
139 D
140 B
141 A
142 B
143 B
144 B
145 B
146 B
147 B
148 B
149 B
150 A
151 C
152 B
153 B
154 C
155 B
156 B
157 B
158 A
159 B
160 B
161 B
162 B
163 B
164 B
165 B
166 B
167 B
168 B
169 B
170 B
171 A
172 B
173 B
174 B
175 B
176 B
177 B
178 B
179 B
180 B
Physics
Section A · worked reasoning
Q001 (C) Candela
Candela is one of the seven base units of the SI system.
Units & Dimensions
Q002 (C) 0.01 mm
Least count = pitch/number of circular scale divisions = 1/100 mm.
Errors & Significant Figures
Q003 (B) 2 m s⁻²
v² = u² − 2as ⇒ 0 = 400 − 2a(100) ⇒ a = 2 m s⁻².
Kinematics
Q004 (B) Zero velocity and acceleration g downwards
Gravity continues to act throughout the flight even where the velocity vanishes.
Kinematics
Q005 (B) Act on two different bodies and never cancel
They form a pair on two different bodies, so they never balance each other.
Laws of Motion
Q006 (B) Linear momentum
Ejecting exhaust gases backwards drives the rocket forwards.
Laws of Motion
Q007 (C) 300 W
P = mgh/t = 60 × 10 × 5/10 = 300 W.
Work, Energy & Power
Q008 (B) 0.5
e = √(h_rebound/h_drop) = √(1/4) = 0.5.
Work, Energy & Power
Q009 (B) 2 kg m² s⁻¹
L = Iω = 0.5 × 4 = 2 kg m² s⁻¹.
Rotational Motion
Q010 (C) ½Iω²
It is the rotational analogue of ½mv².
Rotational Motion
Q011 (B) v_e = √2 v_o
v_o = √(gR) while v_e = √(2gR).
Gravitation
Q012 (B) Zero everywhere inside
The contributions from all parts of the shell cancel at every interior point.
Gravitation
Q013 (B) Proportional limit
Stress is proportional to strain only in the initial linear region of the curve.
Elasticity
Q014 (A) 6πηrv
This is Stokes' law, valid for slow motion of a small sphere.
Fluids
Q015 (B) 8πr²T
A bubble has two surfaces, so W = 2 × 4πr²T.
Fluids
Q016 (B) The temperature difference between the body and its surroundings
The law holds for small temperature differences.
Thermal Properties
Q017 (B) 40%
η = 1 − Q₂/Q₁ = 1 − 0.6 = 0.4 or 40%.
Thermodynamics
Q018 (B) TV^(γ−1) = constant
It follows from PV^γ = constant combined with the ideal gas equation.
Thermodynamics
Q019 (B) Inversely proportional to volume
This is Boyle's law, PV = constant.
Kinetic Theory
Q020 (C) π
a = −ω²x, so acceleration is always opposite in direction to displacement.
Oscillations
Q021 (B) k₁k₂/(k₁ + k₂)
Extensions add in series, so the reciprocals of the force constants add.
Oscillations
Q022 (C) 7 cm
For a phase difference of zero the amplitudes add directly.
Waves
Q023 (B) Logarithmic in intensity
β = 10 log(I/I₀), so each 10 dB step represents a tenfold change in intensity.
Waves
Q024 (C) 90°
τ = pE sinθ is greatest when the dipole is perpendicular to the field.
Electrostatics
Q025 (B) The net electric flux through the surface is zero
Gauss's law fixes the net flux, not the field at individual points.
Electrostatics
Q026 (B) 1 × 10⁻³ C
Q = CV = 5 × 10⁻⁶ × 200 = 10⁻³ C.
Capacitors
Q027 (B) A junction diode
The current–voltage graph of a diode is not a straight line.
Current Electricity
Q028 (B) Infinite resistance and be connected in parallel
A high resistance in parallel draws negligible current from the circuit.
Current Electricity
Q029 (B) A low resistance in parallel
The shunt carries most of the current, protecting the galvanometer coil.
Current Electricity
Q030 (B) 0.1 N
F = BIL sinθ = 0.1 × 2 × 0.5 × 1 = 0.1 N.
Moving Charges & Magnetism
Q031 (B) Uniform and equal to μ₀nI
The field is uniform along the axis in the interior, well away from the ends.
Moving Charges & Magnetism
Q032 (B) M/2
Pole strength is unchanged but the length halves, so the moment halves.
Magnetism & Matter
Q033 (B) Fleming's right hand rule
The left hand rule instead gives the direction of force on a current-carrying conductor.
Electromagnetic Induction
Q034 (B) Using a laminated core
Thin insulated laminations break up the paths available to eddy currents.
Electromagnetic Induction
Q035 (B) R/Z
cos φ = R/Z, which is unity for a purely resistive circuit.
Alternating Current
Q036 (C) 311 V
V₀ = √2 × V_rms = 1.414 × 220 ≈ 311 V.
Alternating Current
Q037 (B) 1/√(μ₀ε₀)
c = 1/√(μ₀ε₀) = 3 × 10⁸ m s⁻¹.
Electromagnetic Waves
Q038 (C) 30 cm
1/v + 1/u = 1/f with the mirror formula gives a real image 30 cm from the mirror.
Ray Optics
Q039 (B) The refractive index of the prism differs for different wavelengths
Violet is deviated most because the material has the largest refractive index for it.
Ray Optics
Q040 (C) I₀/8
The first polaroid gives I₀/2, then Malus' law gives (I₀/2)cos²60° = I₀/8.
Wave Optics
Q041 (B) Decreases as the slit is made wider
The angular width 2λ/a shrinks when a increases.
Wave Optics
Q042 (B) Its mass is very large, making the wavelength immeasurably small
λ = h/mv is of the order of 10⁻³⁴ m for macroscopic objects.
Dual Nature of Matter
Q043 (C) 200 MeV
The mass defect corresponds to roughly 200 MeV per fission event.
Nuclei
Q044 (C) 13.6 eV
The electron must be raised from −13.6 eV to zero energy at n = ∞.
Atoms
Q045 (B) AND
The AND gate performs logical multiplication, Y = A·B.
Semiconductors
Chemistry
Section B · worked reasoning
Q046 (B) 1.204 × 10²⁴
One mole contains 6.022 × 10²³ molecules, each with two atoms.
Some Basic Concepts
Q047 (B) 0.2
x = 2/(2 + 8) = 0.2.
Some Basic Concepts
Q048 (B) E = hc/λ
Since ν = c/λ, E = hν = hc/λ, so shorter wavelength means more energetic photons.
Structure of Atom
Q049 (B) No two electrons in an atom can have the same set of four quantum numbers
This limits any orbital to a maximum of two electrons with opposite spins.
Structure of Atom
Q050 (B) Increases
Increasing atomic size makes the loss of electrons easier down a group.
Classification & Periodicity
Q051 (B) An alkali metal
A single electron in the outermost s orbital is the mark of group 1.
Classification & Periodicity
Q052 (B) sp³d², octahedral
Six bond pairs and no lone pair around sulphur give a regular octahedron.
Chemical Bonding
Q053 (C) H–F
Ionic character increases with the electronegativity difference, greatest for H–F.
Chemical Bonding
Q054 (B) It is formed by head-on axial overlap giving greater overlap
Lateral overlap in a pi bond is less effective than axial overlap.
Chemical Bonding
Q055 (A) 1
With 18 electrons, BO = (10 − 8)/2 = 1, and the ion is diamagnetic.
Chemical Bonding
Q056 (B) −PΔV
Work done by the system on the surroundings is negative by convention.
Thermodynamics
Q057 (B) Zero
There is only one way of arranging a perfect crystal at 0 K, so S = 0.
Thermodynamics
Q058 (B) Shifts the equilibrium in the backward direction
The system opposes the added heat by favouring the endothermic backward reaction.
Equilibrium
Q059 (A) 2.0
A lower pKa corresponds to a larger Ka and therefore a stronger acid.
Equilibrium
Q060 (B) CH₃COOH and CH₃COONa
A weak acid together with its salt of a strong base resists change in pH.
Equilibrium
Q061 (C) +6
2(+1) + x + 4(−2) = 0 ⇒ x = +6.
Redox Reactions
Q062 (B) Decreases rapidly with distance and is negligible beyond three carbons
It is a permanent but weak effect transmitted through sigma bonds.
Organic Chemistry – Basic Principles
Q063 (B) Nitrogen, sulphur and halogens
Fusion with sodium converts these elements into ionisable inorganic compounds.
Organic Chemistry – Basic Principles
Q064 (B) Distance moved by substance/distance moved by solvent
Rf values are characteristic of a compound under fixed conditions.
Organic Chemistry – Basic Principles
Q065 (B) Lower torsional strain
Repulsion between C–H bonding electron pairs is minimised in the staggered form.
Hydrocarbons
Q066 (B) Rotation about the carbon–carbon double bond is restricted
Each doubly bonded carbon carries two different groups.
Hydrocarbons
Q067 (C) Meta position
Deactivating groups such as –NO₂ are meta directing in electrophilic substitution.
Hydrocarbons
Q068 (B) ΔH_mix = 0 and ΔV_mix = 0
Solute–solvent interactions are identical to solute–solute and solvent–solvent ones.
Solutions
Q069 (B) Osmotic pressure at the same temperature
Blood cells stay intact in a solution isotonic with the cell fluid.
Solutions
Q070 (B) 0.00 V
It is assigned zero by convention and used as the reference electrode.
Electrochemistry
Q071 (B) Has a more negative reduction potential and is oxidised in preference to iron
The zinc coating acts as a sacrificial anode.
Electrochemistry
Q072 (B) Pseudo first order kinetics
The concentration of water is effectively constant, so the rate depends only on the ester.
Chemical Kinetics
Q073 (B) Sufficient energy and proper orientation of the colliding molecules
Molecules must collide with energy at least equal to the threshold energy and be correctly aligned.
Chemical Kinetics
Q074 (B) The energies of the ns and (n − 1)d orbitals are comparable
Electrons from both sub-shells can participate in bond formation.
d- and f-Block Elements
Q075 (B) Yellow, forming the chromate ion
Cr₂O₇²⁻ + 2OH⁻ ⇌ 2CrO₄²⁻ + H₂O; the change is reversed on acidification.
d- and f-Block Elements
Q076 (B) A larger number of oxidation states
The 5f, 6d and 7s levels are of comparable energy, allowing many oxidation states.
d- and f-Block Elements
Q077 (C) 4
One complex cation and three chloride ions are produced.
Coordination Compounds
Q078 (B) [Co(en)₃]³⁺
The tris-chelate octahedral complex exists as non-superimposable mirror images.
Coordination Compounds
Q079 (B) Tetracarbonylnickel(0)
Carbon monoxide is a neutral ligand, so nickel is in the zero oxidation state.
Coordination Compounds
Q080 (B) Reacts readily with water to give an alkane
Even traces of moisture destroy the reagent, giving the corresponding hydrocarbon.
Haloalkanes & Haloarenes
Q081 (B) An antiseptic
Its antiseptic action is due to the liberation of free iodine.
Haloalkanes & Haloarenes
Q082 (B) Neutral ferric chloride solution
Phenol gives a violet colouration with neutral FeCl₃ while ethanol does not react.
Alcohols, Phenols & Ethers
Q083 (B) Iodomethane and ethanol
The iodide attacks the less hindered methyl group by SN2.
Alcohols, Phenols & Ethers
Q084 (B) Chromyl chloride
CrO₂Cl₂ oxidises the methyl group only as far as the aldehyde stage.
Aldehydes, Ketones & Carboxylic Acids
Q085 (B) Ethanoic acid > phenol > ethanol
The carboxylate ion is stabilised by two equivalent resonance structures.
Aldehydes, Ketones & Carboxylic Acids
Q086 (B) An aldehyde
Hydrogen with palladium on barium sulphate, partially poisoned, stops at the aldehyde.
Aldehydes, Ketones & Carboxylic Acids
Q087 (B) One carbon atom less
The carbonyl carbon is lost as carbonate during the rearrangement.
Amines
Q088 (B) Aniline
Sn/HCl reduces the nitro group completely to the primary aromatic amine.
Amines
Q089 (B) Ribozymes
Nucleic acids can also act as biological catalysts.
Biomolecules
Q090 (A) Amylose and amylopectin
Amylose is unbranched and helical while amylopectin is branched.
Biomolecules
Botany
Section C · worked reasoning
Q091 (B) Taxon
Insects, mammals and Solanum are all taxa at different ranks.
The Living World
Q092 (B) Conjugation
Conjugation, transformation and transduction bring about genetic recombination in bacteria.
Biological Classification
Q093 (B) Indestructible silica forming a soapbox-like structure
Their accumulated remains over billions of years form diatomaceous earth.
Biological Classification
Q094 (C) W. M. Stanley
Stanley showed that viruses could be crystallised, and the crystals largely consist of proteins.
Biological Classification
Q095 (B) r-Phycoerythrin
This pigment allows red algae to photosynthesise in deeper water.
Plant Kingdom
Q096 (B) One cotyledon and parallel venation
Monocots also typically have a fibrous root system and trimerous flowers.
Plant Kingdom
Q097 (B) Wheat
Monocots such as wheat show a fibrous root system.
Morphology of Flowering Plants
Q098 (B) Pinnately compound
In a pinnately compound leaf the leaflets are borne on a common rachis.
Morphology of Flowering Plants
Q099 (B) Zygomorphic
Pea and Cassia flowers are zygomorphic, or bilaterally symmetrical.
Morphology of Flowering Plants
Q100 (A) Epidermal, ground and vascular
This classification is based on the position of tissues within the plant body.
Anatomy of Flowering Plants
Q101 (B) Multicellular and often branched
Trichomes help prevent water loss, while unicellular root hairs absorb water.
Anatomy of Flowering Plants
Q102 (B) Large, thick walled with no intercellular spaces
This Kranz anatomy is central to the concentration of CO₂ around RuBisCO.
Anatomy of Flowering Plants
Q103 (B) Plasmodesmata
They permit the movement of substances directly from cell to cell.
Cell: The Unit of Life
Q104 (B) Tonoplast
The vacuole may occupy up to 90% of the cell volume and stores ions against a gradient.
Cell: The Unit of Life
Q105 (B) Peroxisome
Peroxisomes are single membrane bound microbodies found in plant and animal cells.
Cell: The Unit of Life
Q106 (B) Micromolecules or metabolites
Proteins, nucleic acids and polysaccharides constitute the acid insoluble fraction.
Biomolecules
Q107 (B) Prosthetic group
The haem group of peroxidase is a prosthetic group.
Biomolecules
Q108 (B) The chromosome number in the daughter cells remains the same as in the parent
Each daughter cell receives an identical set of chromosomes.
Cell Cycle & Cell Division
Q109 (C) Four haploid cells
A single round of replication is followed by two nuclear divisions.
Cell Cycle & Cell Division
Q110 (B) Action spectrum
The absorption spectrum instead plots the light absorbed by a pigment.
Photosynthesis
Q111 (B) Thylakoid membranes and stroma
ATP and NADPH made on the membranes are used for carbon fixation in the stroma.
Photosynthesis
Q112 (B) Cladophora and aerobic bacteria
Aerobic bacteria accumulated where oxygen release was greatest, in the blue and red regions.
Photosynthesis
Q113 (C) 3 ATP
FADH₂ oxidation yields about 2 ATP because it enters the chain at a later point.
Respiration in Plants
Q114 (B) Lactic acid
Lactate dehydrogenase reduces pyruvate, and the accumulation causes cramps.
Respiration in Plants
Q115 (B) Short day plants
The site of light perception is the leaf, and a hormonal signal migrates to the shoot apex.
Plant Growth & Development
Q116 (B) Stimulates stomatal closure and induces dormancy
It increases tolerance to various kinds of stress and antagonises gibberellin.
Plant Growth & Development
Q117 (B) Two celled with a vegetative and a generative cell
In about 40% of species, the generative cell divides first, giving a three celled pollen grain.
Sexual Reproduction in Flowering Plants
Q118 (B) Well exposed stamens and large feathery stigmas
They also produce enormous quantities of light, dry, non-sticky pollen.
Sexual Reproduction in Flowering Plants
Q119 (A) Vallisneria and Zostera
Water pollination is quite rare and limited to about 30 genera, mostly monocots.
Sexual Reproduction in Flowering Plants
Q120 (B) The embryo is protected and provided with reserve food for dispersal
Dormancy and a hard seed coat also allow survival in unfavourable conditions.
Sexual Reproduction in Flowering Plants
Q121 (B) Has several contrasting traits, is self pollinating and has a short life cycle
These features gave him clear-cut, reproducible ratios in large numbers.
Principles of Inheritance
Q122 (B) On different chromosomes or far apart on the same chromosome
Tightly linked genes tend to be inherited together and violate this law.
Principles of Inheritance
Q123 (B) A quantitative defect in the synthesis of globin chains
Too few alpha or beta globin chains are made, though their structure is normal.
Principles of Inheritance
Q124 (B) A frameshift mutation altering the reading frame
All codons downstream of the change are misread.
Principles of Inheritance
Q125 (B) Heterogametic, ZW
The male bird is ZZ, the reverse of the situation in humans.
Principles of Inheritance
Q126 (B) Sulphur and phosphorus
³⁵S labelled the protein coat while ³²P labelled the DNA that entered the bacterium.
Molecular Basis of Inheritance
Q127 (B) Crick
In some retroviruses the flow is reversed, RNA to DNA, by reverse transcriptase.
Molecular Basis of Inheritance
Q128 (B) Methionine
AUG has the dual function of acting as start codon and coding for methionine.
Molecular Basis of Inheritance
Q129 (B) A repetitive non-coding sequence showing high polymorphism
Its repeat copy number varies greatly from individual to individual.
Molecular Basis of Inheritance
Q130 (B) Eurythermal
Stenothermal organisms, by contrast, tolerate only a narrow range.
Organisms & Populations
Q131 (B) Aestivation
Zooplankton in lakes instead enter diapause, a stage of suspended development.
Organisms & Populations
Q132 (B) Grazing food chain
In terrestrial ecosystems a much larger fraction of energy flows through the detritus chain.
Ecosystem
Q133 (B) Inverted
One producer supports a much larger number of primary consumers.
Ecosystem
Q134 (B) Genetic diversity
The plants differ in the potency and concentration of the chemical reserpine.
Biodiversity & Conservation
Q135 (B) Is estimated to produce a large share of the earth's oxygen through photosynthesis
It also harbours probably the greatest biodiversity on earth.
Biodiversity & Conservation
Zoology
Section D · worked reasoning
Q136 (B) Spongocoel
The water current through the canal system aids food gathering, respiration and waste removal.
Animal Kingdom
Q137 (C) Ctenophora
Sea walnuts also show striking bioluminescence.
Animal Kingdom
Q138 (C) Gills covered by an operculum and an air bladder
Chondrichthyes lack both an operculum and a swim bladder.
Animal Kingdom
Q139 (D) Mammals
Mammals also possess external ears and mammary glands.
Animal Kingdom
Q140 (B) Protect and support the neurons
Neuroglia make up more than half the volume of neural tissue.
Structural Organisation in Animals
Q141 (A) Foregut and midgut
These six to eight blind tubules secrete digestive juice.