NEET UG 2026 Mock Test Paper (Set 1) — Free with Answer Key

NEET UG 2026 — Mock Test Paper

Set 1 | Full-Length Practice Paper

Based on Latest NTA Exam Pattern | ChapterNotes.in

Total Questions

200

Maximum Marks

720

Duration

3h 20min

Marking

+4 / −1

General Instructions

  1. This paper contains 200 questions divided into 4 sections: Physics, Chemistry, Botany and Zoology.
  2. Each section has two parts: Section A (35 compulsory questions) and Section B (15 questions, attempt any 10).
  3. Each correct answer carries +4 marks. Each wrong answer carries −1 mark. Unanswered questions carry 0 marks.
  4. Total duration: 3 hours 20 minutes (200 minutes). No extra time for any section.
  5. Use of calculator, log tables, or any electronic device is NOT permitted.
  6. This is an OMR-based offline exam. Mark your answers carefully — there is no option to change once marked.
  7. Assume standard values: g = 10 m/s², speed of light c = 3 × 10⁸ m/s, Planck’s constant h = 6.63 × 10⁻³⁴ J·s unless stated otherwise.

PHYSICS

Section A — Physics (Q1 to Q35)

All 35 questions are compulsory. +4 for correct, −1 for incorrect.

Q1

Two point charges +3 μC and −3 μC are placed 20 cm apart in vacuum. The electric field at the midpoint of the line joining the two charges is:

(a) 5.4 × 10⁶ N/C towards the negative charge
(b) 5.4 × 10⁶ N/C towards the positive charge
(c) 2.7 × 10⁶ N/C towards the negative charge
(d) Zero
Q2

A parallel plate capacitor of capacitance C is charged to a potential V and then disconnected from the battery. If the plates are pulled apart to double the separation, the energy stored in the capacitor becomes:

(a) CV²/2
(b) CV²
(c) CV²/4
(d) 2CV²
Q3

In the circuit shown, the current through the 2 Ω resistor when a 12 V battery with negligible internal resistance is connected across a series combination of 2 Ω, 4 Ω, and 6 Ω resistors is:

(a) 1 A
(b) 2 A
(c) 3 A
(d) 6 A
Q4

A straight conductor of length 0.5 m carrying a current of 2 A is placed in a uniform magnetic field of 0.4 T perpendicular to the conductor. The force on the conductor is:

(a) 0.2 N
(b) 0.4 N
(c) 0.8 N
(d) 1.0 N
Q5

The magnetic susceptibility of a paramagnetic material at temperature T is proportional to:

(a) T
(b)
(c) 1/T
(d) 1/T²
Q6

A circular coil of 100 turns and radius 10 cm is placed in a uniform magnetic field of 0.5 T such that the field is perpendicular to the plane of the coil. If the coil is removed from the field in 0.1 s, the average emf induced is:

(a) 1.57 V
(b) 15.7 V
(c) 0.157 V
(d) 157 V
Q7

In an AC circuit, the rms voltage is 220 V and the rms current is 10 A. If the power consumed is 1100 W, the power factor of the circuit is:

(a) 0.25
(b) 0.5
(c) 0.75
(d) 1.0
Q8

Electromagnetic waves travel in vacuum with a speed equal to:

(a) √(μ₀ε₀)
(b) 1/√(μ₀ε₀)
(c) μ₀ε₀
(d) 1/(μ₀ε₀)
Q9

A convex lens of focal length 20 cm forms a real image of an object placed 30 cm from the lens. The magnification produced is:

(a) −2
(b) +2
(c) −0.5
(d) +0.5
Q10

In Young’s double slit experiment, the fringe width is found to be 0.4 mm. If the entire apparatus is immersed in water of refractive index 4/3, the new fringe width will be:

(a) 0.30 mm
(b) 0.40 mm
(c) 0.53 mm
(d) 0.20 mm
Q11

The work function of a metal is 4.2 eV. The threshold wavelength for photoelectric emission from this metal is approximately:

(a) 2955 Å
(b) 4000 Å
(c) 5000 Å
(d) 6000 Å
Q12

The radius of the first Bohr orbit of hydrogen atom is 0.53 Å. The radius of the third orbit is:

(a) 1.59 Å
(b) 4.77 Å
(c) 2.12 Å
(d) 0.18 Å
Q13

The binding energy per nucleon is maximum for:

(a) ²H
(b) ⁵⁶Fe
(c) ²³⁵U
(d) ⁴He
Q14

In a p-n junction diode under forward bias, the width of the depletion layer:

(a) Increases
(b) Decreases
(c) Remains the same
(d) First increases then decreases
Q15

The dimensional formula of Planck’s constant is the same as that of:

(a) Energy
(b) Force
(c) Angular momentum
(d) Linear momentum
Q16

A block of mass 5 kg is placed on a frictionless surface. A force of 20 N is applied at an angle of 60° with the horizontal. The acceleration of the block is:

(a) 2 m/s²
(b) 4 m/s²
(c) 2√3 m/s²
(d) 1 m/s²
Q17

A body of mass 2 kg is moving with a velocity of 5 m/s. A force is applied on it for 2 seconds and the body attains a velocity of 11 m/s. The work done by the force is:

(a) 96 J
(b) 72 J
(c) 48 J
(d) 36 J
Q18

The escape velocity from the surface of Earth is v. The escape velocity from the surface of a planet having twice the radius and same mean density as Earth is:

(a) v
(b) 2v
(c) v/2
(d) 4v
Q19

A wire of length L and radius r is clamped at one end. If its other end is pulled by a force F, the increase in length is l. If the radius is doubled and length is halved, the increase in length will be:

(a) l
(b) l/2
(c) l/8
(d) l/4
Q20

In an isothermal process, the internal energy of an ideal gas:

(a) Increases
(b) Decreases
(c) Remains constant
(d) May increase or decrease
Q21

A simple pendulum has a time period T. If its length is increased by 21%, the new time period will be approximately:

(a) 1.1T
(b) 1.21T
(c) 1.05T
(d) 0.9T
Q22

The speed of a transverse wave on a stretched string depends on:

(a) Frequency and amplitude
(b) Tension and linear mass density
(c) Wavelength and frequency
(d) Amplitude and wavelength
Q23

The electric flux through a closed surface enclosing a charge q is given by Gauss’s law as:

(a) q/ε₀
(b) q × ε₀
(c) q/4πε₀
(d) 4πq/ε₀
Q24

Three capacitors of capacitance 2 μF, 3 μF and 6 μF are connected in parallel. The equivalent capacitance is:

(a) 1 μF
(b) 11 μF
(c) 6 μF
(d) 0.5 μF
Q25

The resistivity of a semiconductor:

(a) Increases with increase in temperature
(b) Decreases with increase in temperature
(c) Does not change with temperature
(d) First increases then decreases
Q26

A proton and an alpha particle enter a uniform magnetic field perpendicularly with the same speed. The ratio of the radii of their circular paths (r_p : r_α) is:

(a) 1 : 2
(b) 2 : 1
(c) 1 : 4
(d) 4 : 1
Q27

The self-inductance of a long solenoid of length l, cross-sectional area A, and total number of turns N is:

(a) μ₀N²A/l
(b) μ₀NA/l
(c) μ₀N²l/A
(d) μ₀NA²/l
Q28

At resonance in an LCR series circuit, the impedance of the circuit is:

(a) Maximum
(b) Minimum and equal to R
(c) Zero
(d) Equal to √(R² + (X_L − X_C)²)
Q29

Which of the following electromagnetic radiations has the shortest wavelength?

(a) Gamma rays
(b) X-rays
(c) Ultraviolet rays
(d) Microwaves
Q30

A ray of light passes from glass (μ = 1.5) to water (μ = 1.33). The critical angle for total internal reflection is:

(a) sin⁻¹(0.89)
(b) sin⁻¹(0.67)
(c) sin⁻¹(1.13)
(d) sin⁻¹(0.75)
Q31

The de Broglie wavelength associated with an electron accelerated through a potential difference of 100 V is approximately:

(a) 1.227 Å
(b) 0.1227 Å
(c) 12.27 Å
(d) 0.01227 Å
Q32

In Rutherford’s alpha particle scattering experiment, the fraction of alpha particles scattered at angles greater than 90° is approximately:

(a) 50%
(b) 25%
(c) Less than 1%
(d) 10%
Q33

The half-life of a radioactive substance is 30 days. The fraction of the substance that remains after 90 days is:

(a) 1/4
(b) 1/8
(c) 1/3
(d) 1/16
Q34

In a full-wave rectifier using two diodes, the output frequency is:

(a) Same as input frequency
(b) Double the input frequency
(c) Half the input frequency
(d) Four times the input frequency
Q35

A projectile is thrown with a velocity of 20 m/s at an angle of 30° with the horizontal. The maximum height reached is: (g = 10 m/s²)

(a) 5 m
(b) 10 m
(c) 15 m
(d) 20 m

Section B — Physics (Q36 to Q50)

Attempt any 10 out of 15 questions. +4 for correct, −1 for incorrect.

Q36

An electric dipole of moment p is placed in a uniform electric field E. The torque on the dipole is maximum when the angle between p and E is:

(a)
(b) 45°
(c) 90°
(d) 180°
Q37

A galvanometer of resistance 50 Ω gives full-scale deflection for a current of 1 mA. To convert it into a voltmeter of range 0–10 V, the resistance to be connected in series is:

(a) 9950 Ω
(b) 10000 Ω
(c) 950 Ω
(d) 5000 Ω
Q38

A transformer has 500 turns in the primary and 50 turns in the secondary. If the primary voltage is 220 V, the secondary voltage is:

(a) 22 V
(b) 2200 V
(c) 2.2 V
(d) 44 V
Q39

In a single-slit diffraction experiment, the width of the central maximum is:

(a) Twice the width of other secondary maxima
(b) Same as other secondary maxima
(c) Half the width of other secondary maxima
(d) Four times the width of other secondary maxima
Q40

The kinetic energy of photoelectrons emitted from a surface is independent of:

(a) Frequency of incident light
(b) Work function of the surface
(c) Intensity of incident light
(d) Wavelength of incident light
Q41

The energy equivalent of 1 atomic mass unit (amu) is approximately:

(a) 931.5 MeV
(b) 93.15 MeV
(c) 9.315 MeV
(d) 9315 MeV
Q42

The Boolean expression for a NAND gate is:

(a) Y = A + B
(b) Y = A · B
(c) Y = (A · B)’ (complement of A·B)
(d) Y = (A + B)’ (complement of A+B)
Q43

If the momentum of a body is doubled, its kinetic energy becomes:

(a) Double
(b) Four times
(c) Half
(d) Unchanged
Q44

The moment of inertia of a solid sphere about its diameter is (2/5)MR². Its moment of inertia about a tangent is:

(a) (2/5)MR²
(b) (7/5)MR²
(c) (3/5)MR²
(d) MR²
Q45

Two thin lenses of focal lengths +20 cm and −40 cm are placed in contact. The focal length of the combination is:

(a) +40 cm
(b) −40 cm
(c) +20 cm
(d) −20 cm
Q46

A satellite is orbiting the Earth at a height h above the surface. The orbital velocity is v. If the height is doubled, the new orbital velocity will be:

(a) v
(b) v√[(R+h)/(R+2h)]
(c) v/2
(d) 2v
Q47

The efficiency of a Carnot engine working between 127°C and 27°C is:

(a) 25%
(b) 50%
(c) 75%
(d) 78.7%
Q48

Two wires A and B of the same material have their lengths in the ratio 1:2 and radii in the ratio 2:1. The ratio of their resistances R_A : R_B is:

(a) 1 : 8
(b) 8 : 1
(c) 1 : 2
(d) 2 : 1
Q49

In the hydrogen spectrum, the ratio of wavelengths of the first line of the Lyman series to the first line of the Balmer series is:

(a) 5/27
(b) 27/5
(c) 4/9
(d) 9/4
Q50

A body is thrown vertically upward with a velocity u. The distance travelled by the body in the last second of its upward journey is: (g = 10 m/s²)

(a) u/2
(b) 5 m (regardless of u)
(c) 10 m
(d) u − 5

CHEMISTRY

Section A — Chemistry (Q51 to Q85)

All 35 questions are compulsory. +4 for correct, −1 for incorrect.

Q51

The coordination number of each ion in a NaCl crystal structure is:

(a) 4
(b) 6
(c) 8
(d) 12
Q52

The molal elevation constant (K_b) of water is 0.52 K kg mol⁻¹. If 0.1 mol of glucose is dissolved in 500 g of water, the elevation in boiling point is:

(a) 0.052 K
(b) 0.104 K
(c) 0.52 K
(d) 1.04 K
Q53

The standard electrode potential of Zn²⁺/Zn is −0.76 V and Cu²⁺/Cu is +0.34 V. The EMF of the Daniell cell is:

(a) 0.42 V
(b) 1.10 V
(c) −1.10 V
(d) −0.42 V
Q54

For a first-order reaction, the half-life is 10 minutes. The time required for 75% completion is:

(a) 15 minutes
(b) 20 minutes
(c) 30 minutes
(d) 40 minutes
Q55

Which of the following is an example of physisorption?

(a) Adsorption of H₂ on nickel surface
(b) Adsorption of O₂ on tungsten surface
(c) Adsorption of N₂ on mica surface at low temperature
(d) Adsorption of alkenes on nickel surface
Q56

In the extraction of aluminium by Hall-Héroult process, the electrolyte used is:

(a) Pure Al₂O₃
(b) Al₂O₃ dissolved in cryolite (Na₃AlF₆)
(c) Bauxite dissolved in NaOH
(d) AlCl₃ solution
Q57

Which of the following p-block elements does NOT show allotropy?

(a) Carbon
(b) Sulphur
(c) Nitrogen
(d) Phosphorus
Q58

The electronic configuration of Cr (Z = 24) is:

(a) [Ar] 3d⁴ 4s²
(b) [Ar] 3d⁵ 4s¹
(c) [Ar] 3d³ 4s² 4p¹
(d) [Ar] 3d⁶
Q59

The IUPAC name of [Co(NH₃)₄Cl₂]Cl is:

(a) Tetraaminedichloridocobalt(III) chloride
(b) Dichloridotetraaminecobalt(III) chloride
(c) Tetraamminedichloridocobalt(II) chloride
(d) Dichloridotetraamminecobalt(III) chloride
Q60

The reaction of tert-butyl bromide with aqueous NaOH follows:

(a) SN1 mechanism
(b) SN2 mechanism
(c) E2 mechanism
(d) Free radical mechanism
Q61

Which of the following alcohols gives a turbidity within 5 minutes with Lucas reagent at room temperature?

(a) Methanol
(b) Ethanol
(c) 2-Methylpropan-2-ol
(d) Propan-1-ol
Q62

The product formed when acetaldehyde reacts with dilute NaOH is:

(a) Acetone
(b) 3-Hydroxybutanal (aldol)
(c) Ethanol
(d) Acetic acid
Q63

Among the following, the strongest base is:

(a) Aniline
(b) Ethylamine
(c) Acetamide
(d) p-Nitroaniline
Q64

Sucrose on hydrolysis gives:

(a) Glucose + Glucose
(b) Glucose + Fructose
(c) Fructose + Galactose
(d) Glucose + Galactose
Q65

Buna-S rubber is a copolymer of:

(a) 1,3-butadiene and acrylonitrile
(b) 1,3-butadiene and styrene
(c) Isoprene and styrene
(d) Ethylene and propylene
Q66

Which of the following is an antipyretic drug?

(a) Chloramphenicol
(b) Aspirin
(c) Chloroquine
(d) Bithional
Q67

The number of moles of NaOH present in 500 mL of 0.1 M NaOH solution is:

(a) 0.5 mol
(b) 0.05 mol
(c) 0.1 mol
(d) 0.01 mol
Q68

The quantum numbers of the 19th electron of chromium (Z = 24) are:

(a) n=3, l=2, m_l=−2, m_s=+½
(b) n=3, l=2, m_l=0, m_s=+½
(c) n=4, l=0, m_l=0, m_s=+½
(d) n=3, l=1, m_l=−1, m_s=−½
Q69

According to molecular orbital theory, the bond order of O₂ is:

(a) 1
(b) 2
(c) 3
(d) 2.5
Q70

The compressibility factor Z for an ideal gas is:

(a) 0
(b) 1
(c) Greater than 1
(d) Less than 1
Q71

The pH of a 0.01 M HCl solution is:

(a) 1
(b) 2
(c) 3
(d) 0.01
Q72

In the reaction: MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O, the change in oxidation state of Mn is:

(a) +7 to +2
(b) +4 to +2
(c) +7 to +4
(d) +2 to +7
Q73

The IUPAC name of CH₃—CH=CH—CHO is:

(a) But-2-enal
(b) But-3-enal
(c) Crotonic aldehyde
(d) 2-Butenal
Q74

An aqueous solution freezes at −0.186°C. The molality of the solution is: (K_f for water = 1.86 K kg mol⁻¹)

(a) 1 m
(b) 0.1 m
(c) 0.01 m
(d) 10 m
Q75

The number of tetrahedral and octahedral voids per atom in a close-packed structure are respectively:

(a) 1 and 2
(b) 2 and 1
(c) 1 and 1
(d) 2 and 2
Q76

The unit of the rate constant for a second-order reaction is:

(a) s⁻¹
(b) mol L⁻¹ s⁻¹
(c) L mol⁻¹ s⁻¹
(d) L² mol⁻² s⁻¹
Q77

The shape of XeF₄ according to VSEPR theory is:

(a) Tetrahedral
(b) Square planar
(c) See-saw
(d) Square pyramidal
Q78

In the Kolbe reaction, phenol reacts with CO₂ in the presence of NaOH followed by acidification to give:

(a) Benzoic acid
(b) Salicylic acid (2-hydroxybenzoic acid)
(c) Phenyl acetate
(d) Anisole
Q79

The hybridization of the central atom in SF₆ is:

(a) sp³
(b) sp³d
(c) sp³d²
(d) dsp²
Q80

Among the transition elements, the element with the highest number of oxidation states is:

(a) Fe
(b) Mn
(c) Cr
(d) Cu
Q81

The number of isomers possible for the complex [Co(en)₂Cl₂]⁺ is:

(a) 2
(b) 3
(c) 4
(d) 1
Q82

Williamson’s synthesis is used to prepare:

(a) Alcohols
(b) Ethers
(c) Aldehydes
(d) Amines
Q83

Which amino acid is not optically active?

(a) Alanine
(b) Valine
(c) Glycine
(d) Leucine
Q84

The Tyndall effect is exhibited by:

(a) True solutions
(b) Colloidal solutions
(c) Suspensions only
(d) Pure solvents
Q85

The Cannizzaro reaction is given by aldehydes that:

(a) Have α-hydrogen atoms
(b) Do not have α-hydrogen atoms
(c) Are unsaturated
(d) Are cyclic

Section B — Chemistry (Q86 to Q100)

Attempt any 10 out of 15 questions. +4 for correct, −1 for incorrect.

Q86

The van’t Hoff factor (i) for a dilute solution of K₂SO₄ is approximately:

(a) 1
(b) 2
(c) 3
(d) 4
Q87

The molar conductivity of a strong electrolyte at infinite dilution can be obtained by:

(a) Extrapolation of molar conductivity vs √c plot
(b) Kohlrausch’s law
(c) Both (a) and (b)
(d) Neither (a) nor (b)
Q88

The type of colloid formed when a liquid is dispersed in a gas is called:

(a) Foam
(b) Emulsion
(c) Aerosol
(d) Gel
Q89

Interhalogen compound ClF₃ has a shape that is:

(a) Trigonal planar
(b) T-shaped
(c) Pyramidal
(d) Linear
Q90

Which of the following lanthanoid ions is diamagnetic?

(a) Ce³⁺
(b) La³⁺
(c) Eu³⁺
(d) Gd³⁺
Q91

The crystal field splitting energy (Δ₀) in an octahedral complex is affected by the nature of the ligand. The correct order of Δ₀ for the ligands is:

(a) Cl⁻ < H₂O < NH₃ < CN⁻
(b) CN⁻ < NH₃ < H₂O < Cl⁻
(c) H₂O < Cl⁻ < CN⁻ < NH₃
(d) NH₃ < CN⁻ < Cl⁻ < H₂O
Q92

Which of the following reactions gives a primary amine?

(a) Hoffmann bromamide degradation
(b) Friedel-Crafts acylation
(c) Wurtz reaction
(d) Sandmeyer’s reaction
Q93

Nylon-6,6 is a polymer of:

(a) Caprolactam
(b) Hexamethylenediamine and adipic acid
(c) Hexamethylenediamine and sebacic acid
(d) Ethylene glycol and terephthalic acid
Q94

The enthalpy of formation of CO₂(g) is −393.5 kJ/mol. This means:

(a) The reaction is endothermic
(b) 393.5 kJ of heat is released when 1 mol of CO₂ is formed from its elements in standard states
(c) 393.5 kJ of heat is absorbed
(d) CO₂ is unstable
Q95

The reaction CH₃Br + KCN → CH₃CN + KBr is an example of:

(a) Elimination reaction
(b) Nucleophilic substitution reaction
(c) Electrophilic addition reaction
(d) Free radical substitution
Q96

Fehling’s solution is reduced by:

(a) Acetone
(b) Benzaldehyde
(c) Acetaldehyde
(d) Benzoic acid
Q97

The coagulation of a positively charged sol can be most effectively brought about by:

(a) NaCl
(b) Na₂SO₄
(c) Na₃PO₄
(d) KNO₃
Q98

The correct order of increasing acidic strength is:

(a) H₂O < HF < H₂S < HCl
(b) HF < H₂O < HCl < H₂S
(c) H₂O < H₂S < HF < HCl
(d) H₂S < H₂O < HCl < HF
Q99

In the extraction of copper from copper pyrites, the self-reduction step involves:

(a) Cu₂S + 2Cu₂O → 6Cu + SO₂
(b) CuFeS₂ → Cu₂S + FeS
(c) Cu₂O + C → 2Cu + CO
(d) 2Cu + O₂ → 2CuO
Q100

The secondary structure of proteins refers to:

(a) Sequence of amino acids
(b) Regular folding patterns like α-helix and β-pleated sheet
(c) 3D overall shape of the polypeptide
(d) Assembly of multiple polypeptide subunits

BOTANY

Section A — Botany (Q101 to Q135)

All 35 questions are compulsory. +4 for correct, −1 for incorrect.

Q101

In angiosperms, the female gametophyte (embryo sac) is typically:

(a) 8-nucleate and 7-celled
(b) 7-nucleate and 8-celled
(c) 8-nucleate and 8-celled
(d) 6-nucleate and 6-celled
Q102

Double fertilisation in angiosperms involves:

(a) Fusion of two male gametes with the egg cell
(b) Fusion of one male gamete with the egg and one with the secondary nucleus
(c) Fusion of two eggs with two male gametes
(d) Fusion of male gamete with synergid only
Q103

Mendel’s law of independent assortment is applicable when genes are located on:

(a) Same chromosome
(b) Different chromosomes (non-homologous)
(c) Sex chromosomes only
(d) Homologous chromosomes only
Q104

The central dogma of molecular biology describes the flow of genetic information as:

(a) Protein → RNA → DNA
(b) DNA → RNA → Protein
(c) RNA → DNA → Protein
(d) DNA → Protein → RNA
Q105

In the lac operon of E. coli, the inducer molecule is:

(a) Glucose
(b) Lactose (allolactose)
(c) Galactose
(d) Repressor protein
Q106

Green Revolution in India is largely attributed to the development of high-yielding varieties of:

(a) Sugarcane and cotton
(b) Wheat and rice
(c) Maize and sorghum
(d) Pulses and oilseeds
Q107

Curd formation from milk is due to the activity of:

(a) Saccharomyces cerevisiae
(b) Lactobacillus
(c) Acetobacter aceti
(d) Clostridium botulinum
Q108

The enzyme used in recombinant DNA technology to cut DNA at specific sites is:

(a) DNA ligase
(b) DNA polymerase
(c) Restriction endonuclease
(d) Helicase
Q109

Bt cotton is resistant to:

(a) Herbicides
(b) Bollworm (insect pests)
(c) Drought
(d) Fungal diseases
Q110

In a population, the interaction between two species where both are harmed is called:

(a) Mutualism
(b) Commensalism
(c) Competition
(d) Parasitism
Q111

The correct sequence of trophic levels in a food chain is:

(a) Producers → Primary consumers → Secondary consumers → Tertiary consumers
(b) Producers → Secondary consumers → Primary consumers → Decomposers
(c) Decomposers → Producers → Consumers
(d) Primary consumers → Producers → Secondary consumers
Q112

The concept of “biodiversity hotspots” was given by:

(a) Edward Wilson
(b) Norman Myers
(c) Paul Ehrlich
(d) Alexander von Humboldt
Q113

Eutrophication of water bodies is caused mainly by:

(a) Excess oxygen in water
(b) Excess nutrients like nitrogen and phosphorus
(c) Heavy metal contamination
(d) Increase in water temperature only
Q114

The structural and functional unit of the kidney is:

(a) Nephron
(b) Neuron
(c) Glomerulus
(d) Ureter
Q115

The process of DNA replication is:

(a) Conservative
(b) Semi-conservative
(c) Dispersive
(d) Non-conservative
Q116

In the C₄ pathway of photosynthesis, the first stable product is:

(a) 3-phosphoglyceric acid (3-PGA)
(b) Oxaloacetic acid (OAA)
(c) Ribulose bisphosphate (RuBP)
(d) Phosphoenolpyruvate (PEP)
Q117

Casparian strip is found in the:

(a) Epidermis of stem
(b) Endodermis of root
(c) Cortex of root
(d) Pericycle of stem
Q118

Which of the following is a micronutrient for plants?

(a) Nitrogen
(b) Potassium
(c) Zinc
(d) Calcium
Q119

Crossing over occurs during which stage of meiosis?

(a) Leptotene
(b) Pachytene
(c) Diplotene
(d) Diakinesis
Q120

Somaclonal variations are observed in plants raised through:

(a) Seed propagation
(b) Tissue culture
(c) Vegetative propagation
(d) Grafting
Q121

The Ti plasmid, used extensively in plant genetic engineering, is found in:

(a) Escherichia coli
(b) Agrobacterium tumefaciens
(c) Bacillus thuringiensis
(d) Thermus aquaticus
Q122

In ecological succession, the climax community is characterised by:

(a) Pioneer species
(b) Maximum species diversity and stability
(c) Low biomass
(d) Rapid species turnover
Q123

The pollination mechanism in Vallisneria (an aquatic plant) is:

(a) Anemophily (wind pollination)
(b) Entomophily (insect pollination)
(c) Hydrophily (water pollination)
(d) Ornithophily (bird pollination)
Q124

The phenotypic ratio in a monohybrid cross involving incomplete dominance is:

(a) 3 : 1
(b) 1 : 2 : 1
(c) 9 : 3 : 3 : 1
(d) 1 : 1
Q125

The ozone layer in the atmosphere is mainly found in the:

(a) Troposphere
(b) Stratosphere
(c) Mesosphere
(d) Thermosphere
Q126

The net ATP yield from one molecule of glucose during aerobic respiration is:

(a) 24 ATP
(b) 30–32 ATP
(c) 38 ATP
(d) 2 ATP
Q127

The Watson-Crick model of DNA states that the two strands are:

(a) Parallel and held by covalent bonds
(b) Antiparallel and held by hydrogen bonds between complementary base pairs
(c) Parallel and held by hydrogen bonds
(d) Antiparallel and held by ionic bonds
Q128

Which of the following is NOT a greenhouse gas?

(a) CO₂
(b) CH₄
(c) N₂
(d) N₂O
Q129

The enzyme responsible for transcription in eukaryotes that synthesises mRNA is:

(a) RNA polymerase I
(b) RNA polymerase II
(c) RNA polymerase III
(d) Reverse transcriptase
Q130

Polymerase Chain Reaction (PCR) was invented by:

(a) James Watson
(b) Kary Mullis
(c) Har Gobind Khorana
(d) Frederick Sanger
Q131

The part of the flower that develops into a fruit is:

(a) Calyx
(b) Corolla
(c) Ovary
(d) Stamen
Q132

Which of the following is a biodiversity-rich region (hotspot) in India?

(a) Thar Desert
(b) Western Ghats
(c) Indo-Gangetic Plains
(d) Deccan Plateau
Q133

Biogas mainly contains:

(a) Ethane and propane
(b) Methane and CO₂
(c) Hydrogen and oxygen
(d) Nitrogen and ammonia
Q134

The species-area relationship described by Alexander von Humboldt is expressed as:

(a) log S = log C + Z log A
(b) S = CA²
(c) S = C + A
(d) S = C/A
Q135

Transpiration is most rapid when:

(a) Humidity is high and temperature is low
(b) Humidity is low and temperature is high
(c) Both humidity and temperature are low
(d) Both humidity and temperature are high

Section B — Botany (Q136 to Q150)

Attempt any 10 out of 15 questions. +4 for correct, −1 for incorrect.

Q136

Emasculation is carried out in plant breeding to:

(a) Increase seed viability
(b) Prevent self-pollination in bisexual flowers
(c) Promote vegetative growth
(d) Induce polyploidy
Q137

Cyclosporin A, used as an immunosuppressant, is produced by:

(a) Penicillium notatum
(b) Trichoderma polysporum
(c) Monascus purpureus
(d) Aspergillus niger
Q138

Golden Rice has been engineered to produce:

(a) Vitamin C
(b) Beta-carotene (provitamin A)
(c) Iron
(d) Protein
Q139

The pyramid of energy in any ecosystem is always:

(a) Inverted
(b) Upright
(c) Spindle-shaped
(d) Variable
Q140

The endosperm in angiosperms is:

(a) Haploid
(b) Diploid
(c) Triploid
(d) Tetraploid
Q141

A codon consists of:

(a) 2 nucleotides
(b) 3 nucleotides
(c) 4 nucleotides
(d) 1 nucleotide
Q142

Hardy-Weinberg equilibrium is disturbed by:

(a) Random mating
(b) Absence of mutation
(c) Gene flow (migration)
(d) Large population size
Q143

Mycorrhiza is a symbiotic association between:

(a) Algae and fungi
(b) Fungi and plant roots
(c) Bacteria and plant roots
(d) Algae and plant roots
Q144

The restriction enzyme EcoRI recognises the palindromic sequence:

(a) 5′-AAGCTT-3′
(b) 5′-GAATTC-3′
(c) 5′-GGATCC-3′
(d) 5′-CTGCAG-3′
Q145

Kranz anatomy is characteristic of:

(a) C₃ plants
(b) C₄ plants
(c) CAM plants
(d) All photosynthetic plants
Q146

The role of Taq polymerase in PCR is to:

(a) Denature the DNA template
(b) Synthesise new DNA strands at high temperatures
(c) Cut DNA at specific sites
(d) Join DNA fragments
Q147

The vegetative cell in a pollen grain has:

(a) A large nucleus and dense cytoplasm
(b) A small nucleus and sparse cytoplasm
(c) No nucleus
(d) Two nuclei
Q148

In situ conservation includes:

(a) Botanical gardens
(b) Zoos
(c) National parks and wildlife sanctuaries
(d) Seed banks
Q149

The 10% law of energy transfer was given by:

(a) Odum
(b) Lindeman
(c) Tansley
(d) Elton
Q150

Apomixis is:

(a) Formation of seeds with fertilisation
(b) Formation of seeds without fertilisation
(c) Vegetative reproduction by stems
(d) Pollination by wind

ZOOLOGY

Section A — Zoology (Q151 to Q185)

All 35 questions are compulsory. +4 for correct, −1 for incorrect.

Q151

The process of spermatogenesis results in the formation of:

(a) One sperm from one spermatogonium
(b) Two sperms from one spermatogonium
(c) Four sperms from one spermatogonium
(d) Eight sperms from one spermatogonium
Q152

Implantation of the human embryo occurs in the:

(a) Cervix
(b) Fallopian tube
(c) Endometrium of the uterus
(d) Vagina
Q153

Which of the following is NOT a method of contraception?

(a) IUDs (Copper-T)
(b) Vasectomy
(c) IVF (In vitro fertilisation)
(d) Oral contraceptive pills
Q154

According to Darwin, natural selection acts on:

(a) Acquired characters
(b) Heritable variations
(c) Mutations only
(d) All characters equally
Q155

The causative organism of malaria is:

(a) Entamoeba histolytica
(b) Plasmodium
(c) Trypanosoma
(d) Leishmania
Q156

Antibodies are produced by:

(a) T-lymphocytes
(b) B-lymphocytes (plasma cells)
(c) Red blood cells
(d) Platelets
Q157

Which phylum includes organisms with a water vascular system?

(a) Arthropoda
(b) Mollusca
(c) Echinodermata
(d) Annelida
Q158

The characteristic feature of mammals is:

(a) Scales on the body
(b) Presence of mammary glands
(c) Cold-blooded metabolism
(d) External fertilisation
Q159

The connective tissue that connects bone to bone is:

(a) Tendon
(b) Ligament
(c) Cartilage
(d) Areolar tissue
Q160

Pepsin acts in the stomach because it is active at:

(a) pH 7.0 (neutral)
(b) pH 1.5–2.0 (acidic)
(c) pH 8.5 (alkaline)
(d) pH 10 (strongly alkaline)
Q161

The oxygen-carrying pigment in human blood is:

(a) Myoglobin
(b) Haemoglobin
(c) Haemocyanin
(d) Chlorocruorin
Q162

The vital capacity of the lungs is the sum of:

(a) Tidal volume + Inspiratory reserve volume + Expiratory reserve volume
(b) Tidal volume + Residual volume
(c) Inspiratory reserve volume + Expiratory reserve volume
(d) Tidal volume only
Q163

The SA node (sinoatrial node) in the heart is located in the:

(a) Left atrium
(b) Right atrium
(c) Left ventricle
(d) Right ventricle
Q164

Juxtaglomerular cells in the kidney produce:

(a) ADH (antidiuretic hormone)
(b) Renin
(c) Aldosterone
(d) Erythropoietin
Q165

The joint between the atlas and axis vertebrae is a:

(a) Hinge joint
(b) Pivot joint
(c) Ball and socket joint
(d) Gliding joint
Q166

The part of the brain that controls body temperature, hunger, and thirst is:

(a) Cerebrum
(b) Cerebellum
(c) Hypothalamus
(d) Medulla oblongata
Q167

Insulin is secreted by:

(a) Alpha cells of Islets of Langerhans
(b) Beta cells of Islets of Langerhans
(c) Delta cells of Islets of Langerhans
(d) Acinar cells of pancreas
Q168

The acrosome of a sperm is derived from:

(a) Mitochondria
(b) Golgi apparatus
(c) Endoplasmic reticulum
(d) Ribosomes
Q169

MTP (Medical Termination of Pregnancy) is considered safe up to:

(a) 6 weeks
(b) 12 weeks
(c) 20 weeks
(d) 24 weeks
Q170

Analogous organs are a result of:

(a) Divergent evolution
(b) Convergent evolution
(c) Parallel evolution
(d) Co-evolution
Q171

HIV (Human Immunodeficiency Virus) attacks which type of cells?

(a) B-cells
(b) Helper T-cells (CD4+)
(c) Red blood cells
(d) Platelets
Q172

Bile is produced by the:

(a) Gall bladder
(b) Stomach
(c) Liver
(d) Pancreas
Q173

The exchange of gases in the lungs occurs at the:

(a) Bronchi
(b) Bronchioles
(c) Alveoli
(d) Trachea
Q174

Blood group antigens are present on:

(a) WBCs
(b) Platelets
(c) RBCs
(d) Plasma proteins
Q175

The functional unit of muscle contraction is:

(a) Myofibril
(b) Sarcomere
(c) Muscle fibre
(d) Fascicle
Q176

The hormone responsible for the fight-or-flight response is:

(a) Insulin
(b) Thyroxine
(c) Adrenaline (epinephrine)
(d) Melatonin
Q177

Turner’s syndrome is characterised by the karyotype:

(a) 44 + XXY
(b) 44 + XO
(c) 44 + XXX
(d) 44 + XYY
Q178

The first organisms to appear on Earth were:

(a) Aerobic autotrophs
(b) Anaerobic heterotrophs
(c) Aerobic heterotrophs
(d) Anaerobic autotrophs
Q179

Colostrum is important for the newborn because it contains:

(a) High fat content
(b) IgA antibodies
(c) Carbohydrates only
(d) Vitamins only
Q180

Oogenesis in human females produces:

(a) Four functional ova
(b) One ovum and three polar bodies
(c) Two ova and two polar bodies
(d) Three ova and one polar body
Q181

Interferons are proteins released by virus-infected cells that:

(a) Kill the virus directly
(b) Protect neighbouring cells from viral infection
(c) Produce antibodies
(d) Increase viral replication
Q182

The loop of Henle in a nephron is primarily responsible for:

(a) Filtration of blood
(b) Secretion of urea
(c) Concentration of urine (countercurrent mechanism)
(d) Reabsorption of glucose only
Q183

During muscle contraction, which of the following shortens?

(a) A-band
(b) I-band and H-zone
(c) Actin filaments
(d) Myosin filaments
Q184

The cranial nerve responsible for vision is:

(a) Olfactory nerve (I)
(b) Optic nerve (II)
(c) Oculomotor nerve (III)
(d) Vagus nerve (X)
Q185

Addison’s disease is caused by the hyposecretion of hormones from:

(a) Thyroid gland
(b) Adrenal cortex
(c) Pituitary gland
(d) Pancreas

Section B — Zoology (Q186 to Q200)

Attempt any 10 out of 15 questions. +4 for correct, −1 for incorrect.

Q186

The placenta is formed by the interdigitation of chorionic villi with:

(a) Myometrium
(b) Uterine endometrium (decidua)
(c) Perimetrium
(d) Cervical mucosa
Q187

STDs that can be transmitted through sexual contact include:

(a) Typhoid and cholera
(b) Syphilis and gonorrhoea
(c) Malaria and dengue
(d) Tuberculosis and pneumonia
Q188

Industrial melanism in peppered moths is an example of:

(a) Genetic drift
(b) Natural selection
(c) Mutation
(d) Bottleneck effect
Q189

The widal test is used for the diagnosis of:

(a) Malaria
(b) Typhoid
(c) AIDS
(d) Cholera
Q190

Organisms belonging to phylum Cnidaria possess:

(a) Nematocysts
(b) Parapodia
(c) Tube feet
(d) Setae
Q191

The enzyme trypsin acts on:

(a) Fats
(b) Proteins
(c) Starch
(d) Nucleic acids
Q192

The Bohr effect describes the influence of CO₂ concentration on:

(a) Breathing rate
(b) Oxygen-binding capacity of haemoglobin
(c) Blood pressure
(d) Heart rate
Q193

In humans, erythropoietin is primarily produced by:

(a) Liver
(b) Kidneys
(c) Spleen
(d) Bone marrow
Q194

The neurotransmitter released at the neuromuscular junction is:

(a) Dopamine
(b) Serotonin
(c) Acetylcholine
(d) GABA
Q195

Gigantism is caused by hypersecretion of growth hormone during:

(a) Old age
(b) Childhood
(c) Adulthood only
(d) Prenatal period
Q196

Adaptive radiation refers to:

(a) Evolution of a single species from multiple ancestors
(b) Evolution of different species from a common ancestor in different habitats
(c) Random genetic changes
(d) Extinction of species
Q197

Which of the following is an autoimmune disease?

(a) AIDS
(b) Rheumatoid arthritis
(c) Dengue
(d) Malaria
Q198

The human spinal cord is protected by:

(a) Cranium
(b) Vertebral column
(c) Sternum
(d) Ribs
Q199

Corpus luteum secretes which hormone to maintain pregnancy?

(a) Estrogen only
(b) Progesterone
(c) FSH
(d) LH
Q200

Darwin’s finches of Galapagos Islands provide evidence of:

(a) Convergent evolution
(b) Adaptive radiation
(c) Parallel evolution
(d) Genetic drift

PHYSICS — Answer Key (Q1–Q50)

Q1. (a) Both fields point from + to − at midpoint. E = 2 × kq/r² = 2 × 9×10⁹ × 3×10⁻⁶/0.01 = 5.4 × 10⁶ N/C towards negative charge.
Q2. (b) After disconnection, charge Q is constant. Doubling separation halves capacitance (C/2). Energy = Q²/2C’ = Q²/(2×C/2) = Q²/C = 2 × (Q²/2C) = 2 × CV²/2 = CV².
Q3. (a) Total resistance = 2 + 4 + 6 = 12 Ω. I = V/R = 12/12 = 1 A. Same current flows through all resistors in series.
Q4. (b) F = BIL sin90° = 0.4 × 2 × 0.5 × 1 = 0.4 N.
Q5. (c) Curie’s law: χ = C/T. Susceptibility is inversely proportional to temperature for paramagnetic materials.
Q6. (b) EMF = NΔΦ/Δt = N×B×A/Δt = 100 × 0.5 × π(0.1)² / 0.1 = 100 × 0.5 × 0.0314/0.1 = 15.7 V.
Q7. (b) Power factor = P/(V_rms × I_rms) = 1100/(220 × 10) = 0.5.
Q8. (b) Speed of EM waves in vacuum c = 1/√(μ₀ε₀). This is a fundamental result from Maxwell’s equations.
Q9. (a) 1/v − 1/u = 1/f. u = −30, f = 20. 1/v = 1/20 − 1/30 = 1/60. v = 60 cm. m = v/u = 60/(−30) = −2.
Q10. (a) Fringe width β = λD/d. In medium of refractive index μ, λ’ = λ/μ. New β = β/μ = 0.4 × 3/4 = 0.30 mm.
Q11. (a) λ₀ = hc/φ = (6.63×10⁻³⁴ × 3×10⁸)/(4.2 × 1.6×10⁻¹⁹) = 2955 Å.
Q12. (b) r_n = r₁ × n². r₃ = 0.53 × 9 = 4.77 Å.
Q13. (b) ⁵⁶Fe has the maximum binding energy per nucleon (~8.75 MeV), making it the most stable nucleus.
Q14. (b) Under forward bias, the external voltage opposes the barrier potential, reducing the depletion layer width.
Q15. (c) [h] = E/ν = ML²T⁻² × T = ML²T⁻¹, same as angular momentum (L = mvr = ML²T⁻¹).
Q16. (a) Horizontal component = F cos60° = 20 × 0.5 = 10 N. a = F_h/m = 10/5 = 2 m/s².
Q17. (a) Work = ΔKE = ½m(v² − u²) = ½ × 2 × (121 − 25) = 96 J.
Q18. (b) v_e = √(2gR) = √(2 × 4/3πGρR² × R) ∝ R. Doubling R doubles escape velocity.
Q19. (c) Δl = FL/(πr²Y). New: F(L/2)/(π(2r)²Y) = FL/(8πr²Y) = l/8.
Q20. (c) For an ideal gas, internal energy depends only on temperature. In isothermal process, T is constant, so U is constant.
Q21. (a) T’ = T√(1.21) = T × 1.1 = 1.1T.
Q22. (b) v = √(T/μ) where T is tension and μ is linear mass density.
Q23. (a) Gauss’s law: Φ = q/ε₀. This is a fundamental law in electrostatics.
Q24. (b) In parallel: C_eq = 2 + 3 + 6 = 11 μF.
Q25. (b) In semiconductors, increasing temperature provides energy for electrons to cross the band gap, increasing conductivity and decreasing resistivity.
Q26. (a) r = mv/qB. r_p/r_α = (m_p × v)/(q_p × B) ÷ (m_α × v)/(q_α × B) = (m_p/q_p)/(m_α/q_α) = (m_p × q_α)/(m_α × q_p) = (1 × 2)/(4 × 1) = 1:2.
Q27. (a) L = μ₀N²A/l. This is the standard formula for self-inductance of a solenoid.
Q28. (b) At resonance, X_L = X_C, so impedance Z = R (minimum value). Current is maximum.
Q29. (a) Gamma rays have the shortest wavelength (highest frequency/energy) in the electromagnetic spectrum.
Q30. (a) sin C = μ_water/μ_glass = 1.33/1.5 = 0.887 ≈ 0.89. C = sin⁻¹(0.89).
Q31. (a) λ = 12.27/√V Å = 12.27/√100 = 12.27/10 = 1.227 Å.
Q32. (c) Most alpha particles pass straight through. Only a very small fraction (less than 1%) are scattered at large angles (>90°), indicating a small dense nucleus.
Q33. (b) 90 days = 3 half-lives. Fraction remaining = (1/2)³ = 1/8.
Q34. (b) Full-wave rectifier rectifies both halves of input cycle, so output frequency = 2 × input frequency.
Q35. (a) H = u²sin²θ/(2g) = 400 × (0.5)²/(2 × 10) = 400 × 0.25/20 = 5 m.
Q36. (c) τ = pE sinθ. Maximum when θ = 90°.
Q37. (a) R = V/I_g − G = 10/0.001 − 50 = 10000 − 50 = 9950 Ω.
Q38. (a) V_s/V_p = N_s/N_p. V_s = 220 × 50/500 = 22 V.
Q39. (a) In single-slit diffraction, the central maximum is twice as wide as any secondary maximum.
Q40. (c) KE_max = hν − φ. It depends on frequency (wavelength) and work function, but NOT on intensity.
Q41. (a) 1 amu = 931.5 MeV/c². This is a standard conversion factor.
Q42. (c) NAND gate output is the complement of AND: Y = (A·B)’ = NOT(A AND B).
Q43. (b) KE = p²/(2m). If p doubles, KE becomes 4 times.
Q44. (b) By parallel axis theorem: I_tangent = I_diameter + MR² = 2MR²/5 + MR² = 7MR²/5.
Q45. (a) 1/f = 1/f₁ + 1/f₂ = 1/20 + 1/(−40) = 2/40 − 1/40 = 1/40. f = +40 cm.
Q46. (b) v_orbital = √(GM/(R+h)). When h doubles: v’ = v√[(R+h)/(R+2h)].
Q47. (a) η = 1 − T₂/T₁ = 1 − 300/400 = 1 − 0.75 = 0.25 = 25%. (Convert to Kelvin: 127+273=400K, 27+273=300K).
Q48. (a) R = ρL/(πr²). R_A/R_B = (L_A/L_B)(r_B/r_A)² = (1/2)(1/2)² = (1/2)(1/4) = 1/8.
Q49. (a) Lyman 1st: 1/λ_L = R(1 − 1/4) = 3R/4. Balmer 1st: 1/λ_B = R(1/4 − 1/9) = 5R/36. λ_L/λ_B = (4/3R)/(36/5R) = 20/108 = 5/27.
Q50. (b) In the last second before reaching the top, u_eff = g × 1 = 10 × 1. Distance = u(1) − ½g(1)² where velocity at start of last second = g×1 = 10. So d = 10(1) − ½(10)(1) = 5 m, regardless of initial velocity.

CHEMISTRY — Answer Key (Q51–Q100)

Q51. (b) In NaCl (rock salt) structure, each Na⁺ is surrounded by 6 Cl⁻ and each Cl⁻ by 6 Na⁺. Coordination number = 6.
Q52. (b) ΔT_b = K_b × m = 0.52 × (0.1/0.5) = 0.52 × 0.2 = 0.104 K.
Q53. (b) E_cell = E_cathode − E_anode = 0.34 − (−0.76) = 1.10 V.
Q54. (b) For 75% completion, 25% remains. (1/2)^n = 0.25, so n = 2 half-lives. t = 2 × 10 = 20 minutes.
Q55. (c) Physisorption involves weak van der Waals forces, is reversible, and occurs at low temperature. N₂ on mica at low temp is physisorption.
Q56. (b) In Hall-Héroult process, purified Al₂O₃ (alumina) is dissolved in molten cryolite (Na₃AlF₆) to lower the melting point.
Q57. (c) Nitrogen does not show allotropy. Carbon (diamond, graphite), sulphur (rhombic, monoclinic), and phosphorus (white, red, black) show allotropy.
Q58. (b) Cr has anomalous configuration [Ar] 3d⁵ 4s¹ due to extra stability of half-filled d-orbitals.
Q59. (d) IUPAC: ligands listed alphabetically — ammine before chlorido. Metal oxidation state: +3. Name: Dichloridotetraamminecobalt(III) chloride.
Q60. (a) Tertiary alkyl halides follow S_N1 due to stable tertiary carbocation intermediate. Steric hindrance prevents S_N2.
Q61. (c) Tertiary alcohols react immediately (within 5 min) with Lucas reagent (ZnCl₂/HCl) giving turbidity.
Q62. (b) Aldol condensation: CH₃CHO with dilute NaOH gives 3-hydroxybutanal (aldol product).
Q63. (b) Ethylamine (aliphatic amine) is a stronger base than aniline (aromatic amine) due to +I effect of ethyl group and no resonance deactivation.
Q64. (b) Sucrose (table sugar) on hydrolysis yields glucose + fructose. This mixture is called invert sugar.
Q65. (b) Buna-S (Styrene-Butadiene Rubber) is a copolymer of 1,3-butadiene and styrene.
Q66. (b) Aspirin (acetylsalicylic acid) is an antipyretic (fever-reducing), analgesic, and anti-inflammatory drug.
Q67. (b) Moles = M × V(in L) = 0.1 × 0.5 = 0.05 mol.
Q68. (a) Cr: [Ar] 3d⁵ 4s¹. The 19th electron enters 3d orbital. First 3d electron: n=3, l=2, m_l=−2, m_s=+½.
Q69. (b) O₂: Bond order = (N_b − N_a)/2 = (10−6)/2 = 2. O₂ is paramagnetic with bond order 2.
Q70. (b) Z = PV/nRT. For ideal gas, PV = nRT, so Z = 1.
Q71. (b) pH = −log[H⁺] = −log(0.01) = −log(10⁻²) = 2.
Q72. (a) In MnO₄⁻, Mn is +7. In Mn²⁺, it is +2. Change: +7 → +2 (gain of 5 electrons).
Q73. (a) CH₃−CH=CH−CHO: The double bond is at position 2, aldehyde at position 1. IUPAC: But-2-enal.
Q74. (b) ΔT_f = K_f × m. m = ΔT_f/K_f = 0.186/1.86 = 0.1 m.
Q75. (b) In close-packed structure: tetrahedral voids = 2 per atom, octahedral voids = 1 per atom.
Q76. (c) For second-order: rate = k[A]². k = rate/[A]² → units: (mol/L·s)/(mol/L)² = L mol⁻¹ s⁻¹.
Q77. (b) XeF₄: Xe has 2 lone pairs + 4 bond pairs (sp³d² hybridised). Shape is square planar.
Q78. (b) Kolbe’s reaction: Phenol + CO₂ + NaOH (high T, P) → sodium salicylate → salicylic acid (2-hydroxybenzoic acid).
Q79. (c) SF₆: S is bonded to 6 F atoms, no lone pairs → sp³d² hybridisation, octahedral shape.
Q80. (b) Mn shows oxidation states from +2 to +7 (highest among 3d elements), giving it the most oxidation states.
Q81. (b) [Co(en)₂Cl₂]⁺ shows 3 isomers: cis (which has optical isomers — d and l forms) and trans. Total = 3.
Q82. (b) Williamson’s synthesis: R−O⁻Na⁺ + R’−X → R−O−R’ (ether). It is the standard method for preparing ethers.
Q83. (c) Glycine (H₂N−CH₂−COOH) has no chiral carbon (R = H), so it is optically inactive.
Q84. (b) Tyndall effect (scattering of light) is characteristic of colloidal solutions due to their particle size (1-1000 nm).
Q85. (b) Cannizzaro reaction is given by aldehydes without α-hydrogen (e.g., formaldehyde, benzaldehyde). One molecule is oxidised and one reduced.
Q86. (c) K₂SO₄ → 2K⁺ + SO₄²⁻ (3 ions). Van’t Hoff factor i = 3 for complete dissociation.
Q87. (c) For strong electrolytes: both extrapolation and Kohlrausch’s law work. For weak electrolytes, only Kohlrausch’s law is reliable.
Q88. (c) Liquid dispersed in gas = aerosol (e.g., fog, mist, cloud).
Q89. (b) ClF₃: Cl has 3 bond pairs + 2 lone pairs (sp³d hybridised). Shape is T-shaped.
Q90. (b) La³⁺ has [Xe] configuration with no unpaired electrons (4f⁰), making it diamagnetic.
Q91. (a) Spectrochemical series: I⁻ < Br⁻ < Cl⁻ < F⁻ < OH⁻ < H₂O < NH₃ < en < NO₂⁻ < CN⁻ < CO. So Cl⁻ < H₂O < NH₃ < CN⁻.
Q92. (a) Hoffmann bromamide degradation: RCONH₂ + Br₂ + 4NaOH → RNH₂ + Na₂CO₃ + 2NaBr + 2H₂O. Gives primary amine with one fewer carbon.
Q93. (b) Nylon-6,6 is made by condensation of hexamethylenediamine (6C) and adipic acid (6C) — hence the name 6,6.
Q94. (b) Negative ΔH_f means heat is released (exothermic). 393.5 kJ released when 1 mol CO₂ is formed from C(graphite) + O₂(g).
Q95. (b) CN⁻ (nucleophile) attacks the electrophilic carbon, displacing Br⁻ (leaving group). This is nucleophilic substitution.
Q96. (c) Fehling’s solution is reduced by aliphatic aldehydes (acetaldehyde). Benzaldehyde does not reduce it. Ketones don’t react.
Q97. (c) Hardy-Schulze rule: higher the charge of the coagulating ion (opposite to sol), greater the coagulating power. PO₄³⁻ (charge 3−) is most effective.
Q98. (a) Acid strength increases across a period (HF > H₂O) and down a group (HCl > HF, H₂S > H₂O). Overall: H₂O < HF < H₂S < HCl.
Q99. (a) Self-reduction (bessemerisation): Cu₂S + 2Cu₂O → 6Cu + SO₂↑. Cu₂O oxidises Cu₂S without external reducing agent.
Q100. (b) Secondary structure: regular folding patterns stabilised by hydrogen bonds — α-helix and β-pleated sheet.

BOTANY — Answer Key (Q101–Q150)

Q101. (a) Embryo sac: 8 nucleate, 7 celled — 1 egg, 2 synergids, 3 antipodals, 1 central cell (2 polar nuclei).
Q102. (b) Double fertilisation: one male gamete fuses with egg (→ zygote, 2n) and other fuses with secondary nucleus/polar nuclei (→ endosperm, 3n).
Q103. (b) Independent assortment requires genes to be on different (non-homologous) chromosomes. Linked genes don’t assort independently.
Q104. (b) Central dogma: DNA → (transcription) → RNA → (translation) → Protein. Proposed by Crick.
Q105. (b) Lactose (specifically allolactose, an isomer) is the inducer that binds to the repressor, freeing the operator for transcription.
Q106. (b) Green Revolution (1960s-70s): HYV of wheat (by Norman Borlaug/M.S. Swaminathan) and rice transformed Indian agriculture.
Q107. (b) Lactobacillus converts lactose in milk to lactic acid, causing coagulation of milk protein (casein) to form curd.
Q108. (c) Restriction endonucleases (molecular scissors) cut DNA at specific palindromic recognition sequences.
Q109. (b) Bt cotton contains cry gene from Bacillus thuringiensis, producing Cry protein toxic to bollworm larvae.
Q110. (c) Competition (−/−): both species are harmed. They compete for same resources. Differs from parasitism (+/−) and mutualism (+/+).
Q111. (a) Food chain: Producers → Primary consumers (herbivores) → Secondary consumers (carnivores) → Tertiary consumers (top predators).
Q112. (b) Norman Myers coined the term “biodiversity hotspot” in 1988 for regions with high species richness and endemism under threat.
Q113. (b) Eutrophication: excess nutrients (N, P) from fertilisers/sewage cause algal blooms, oxygen depletion, and death of aquatic life.
Q114. (a) Nephron is the structural and functional unit of the kidney, responsible for filtration, reabsorption, and secretion.
Q115. (b) DNA replication is semi-conservative — each new DNA molecule has one old strand and one new strand (Meselson-Stahl experiment).
Q116. (b) In C₄ plants, the first CO₂ fixation product is OAA (4-carbon compound), formed by PEP carboxylase in mesophyll cells.
Q117. (b) Casparian strip is a band of suberin in the endodermis of roots that controls water and mineral movement into the stele.
Q118. (c) Zinc is a micronutrient. N, K, Ca are macronutrients (required in larger amounts).
Q119. (b) Crossing over occurs during pachytene stage of prophase I (meiosis), when homologous chromosomes form bivalents/tetrads.
Q120. (b) Somaclonal variations arise in plants regenerated from tissue culture (in vitro) due to chromosomal/genetic changes during callus formation.
Q121. (b) Ti (Tumor-inducing) plasmid is found in Agrobacterium tumefaciens. T-DNA region is used to transfer genes into plants.
Q122. (b) Climax community is the final, stable community in ecological succession with maximum species diversity and biomass.
Q123. (c) Vallisneria shows hydrophily — male flowers are released on water surface and float to female flowers for pollination.
Q124. (b) Incomplete dominance: F₂ ratio is 1:2:1 (phenotypic = genotypic). E.g., snapdragon flower colour: Red:Pink:White.
Q125. (b) Ozone layer is located in the stratosphere (15-35 km altitude), protecting life from harmful UV radiation.
Q126. (b) Net ATP yield from aerobic respiration of glucose is approximately 30-32 ATP (by current estimates using the chemiosmotic model).
Q127. (b) Watson-Crick model: two antiparallel strands (5’→3′ and 3’→5′) held by H-bonds between A=T (2 bonds) and G≡C (3 bonds).
Q128. (c) N₂ is not a greenhouse gas. CO₂, CH₄, and N₂O absorb and re-emit infrared radiation. N₂ is transparent to IR.
Q129. (b) RNA polymerase II transcribes mRNA (hnRNA) in eukaryotes. RNA Pol I makes rRNA, RNA Pol III makes tRNA and 5S rRNA.
Q130. (b) Kary Mullis invented PCR in 1983, winning the Nobel Prize in Chemistry (1993) for this revolutionary technique.
Q131. (c) The ovary of the flower develops into the fruit after fertilisation. Ovules develop into seeds.
Q132. (b) India has 4 biodiversity hotspots. Western Ghats is one of them (others: Himalayas, Indo-Burma, Sundaland).
Q133. (b) Biogas is produced by methanogenic bacteria. It mainly contains methane (50-70%) and CO₂ (30-40%).
Q134. (a) Species-Area relationship: log S = log C + Z log A, where S = species richness, A = area, Z = regression coefficient, C = y-intercept.
Q135. (b) Transpiration increases with low humidity (dry air) and high temperature (increases water vapour capacity of air).
Q136. (b) Emasculation (removal of anthers) prevents self-pollination in bisexual flowers during hybridisation experiments.
Q137. (b) Cyclosporin A is produced by the fungus Trichoderma polysporum. It is used to prevent organ transplant rejection.
Q138. (b) Golden Rice is genetically engineered to produce beta-carotene (provitamin A) to address vitamin A deficiency.
Q139. (b) Pyramid of energy is always upright because energy decreases at each successive trophic level (10% law).
Q140. (c) Endosperm is triploid (3n) — formed by fusion of one male gamete (n) with two polar nuclei (n + n = 2n).
Q141. (b) A codon is a triplet of three consecutive nucleotides on mRNA that codes for a specific amino acid.
Q142. (c) Gene flow (migration) disturbs Hardy-Weinberg equilibrium by introducing new alleles or changing allele frequencies.
Q143. (b) Mycorrhiza is a symbiotic association between fungi and plant roots. Fungus helps in mineral/water absorption.
Q144. (b) EcoRI recognises 5′-GAATTC-3′ and cuts between G and A, producing sticky ends. Named after E. coli strain RY13.
Q145. (b) Kranz anatomy (wreath-like arrangement of bundle sheath cells around vascular bundles) is characteristic of C₄ plants.
Q146. (b) Taq polymerase (from Thermus aquaticus) is thermostable and synthesises new DNA at high temperatures during PCR extension step.
Q147. (a) The vegetative cell is larger with a big irregularly shaped nucleus and dense cytoplasm. The generative cell is smaller.
Q148. (c) In situ conservation preserves species in their natural habitat — national parks, wildlife sanctuaries, biosphere reserves.
Q149. (b) Lindeman (1942) proposed the 10% law — only 10% of energy is transferred from one trophic level to the next.
Q150. (b) Apomixis: production of seeds without fertilisation. Seeds are genetically identical to parent (clones). E.g., some grasses, Asteraceae.

ZOOLOGY — Answer Key (Q151–Q200)

Q151. (c) One primary spermatocyte → 2 secondary spermatocytes → 4 spermatids → 4 sperms. Four functional sperms from one spermatogonium.
Q152. (c) Implantation occurs when the blastocyst embeds in the endometrium of the uterus, approximately 6-7 days after fertilisation.
Q153. (c) IVF is an assisted reproductive technology (ART), not a contraceptive method. It helps infertile couples conceive.
Q154. (b) Natural selection acts on heritable variations — traits that can be passed to offspring and provide survival/reproductive advantage.
Q155. (b) Malaria is caused by Plasmodium species (P. vivax, P. falciparum, P. malariae, P. ovale), transmitted by female Anopheles mosquito.
Q156. (b) B-lymphocytes differentiate into plasma cells that produce antibodies (immunoglobulins) for humoral immunity.
Q157. (c) Echinodermata (starfish, sea urchins) have a unique water vascular system used for locomotion, feeding, and respiration.
Q158. (b) Mammary glands (for milk production to nourish young) are the defining characteristic of mammals.
Q159. (b) Ligaments connect bone to bone. Tendons connect muscle to bone. Both are dense connective tissues.
Q160. (b) Pepsin requires acidic pH (1.5-2.0). HCl in gastric juice provides this acidic environment and activates pepsinogen to pepsin.
Q161. (b) Haemoglobin (in RBCs) binds O₂ to form oxyhaemoglobin. Each Hb molecule can carry 4 O₂ molecules.
Q162. (a) Vital capacity = TV + IRV + ERV (maximum air that can be exhaled after maximum inhalation). ~4500 mL in males.
Q163. (b) SA node (pacemaker) is in the right atrium near the opening of the superior vena cava. It initiates the heartbeat.
Q164. (b) JG cells produce renin (an enzyme) that initiates the RAAS pathway, regulating blood pressure and fluid balance.
Q165. (b) Atlas-axis joint is a pivot joint, allowing rotational movement (turning the head side to side).
Q166. (c) Hypothalamus is the master control centre for homeostasis — regulates body temperature, hunger, thirst, circadian rhythms.
Q167. (b) Beta cells of Islets of Langerhans secrete insulin (lowers blood glucose). Alpha cells secrete glucagon (raises blood glucose).
Q168. (b) The acrosome (cap-like structure on sperm head) is derived from the Golgi apparatus. It contains enzymes for penetrating the egg.
Q169. (b) MTP is considered safe during the first trimester (up to 12 weeks). After that, risks increase significantly.
Q170. (b) Analogous organs (same function, different origin) arise through convergent evolution. E.g., wings of insects and birds.
Q171. (b) HIV attacks helper T-cells (CD4⁺ cells), crippling the immune system and leading to AIDS.
Q172. (c) Bile is produced by hepatocytes in the liver. Gall bladder only stores and concentrates bile.
Q173. (c) Gas exchange occurs at the alveoli — thin-walled air sacs with extensive capillary network for efficient O₂/CO₂ exchange.
Q174. (c) ABO blood group antigens (glycoproteins) are present on the surface of red blood cells. Antibodies are in plasma.
Q175. (b) Sarcomere (region between two Z-lines) is the functional unit of muscle contraction. Contains actin and myosin filaments.
Q176. (c) Adrenaline (epinephrine) from adrenal medulla triggers fight-or-flight: increased heart rate, blood pressure, and glucose release.
Q177. (b) Turner’s syndrome: 44 + XO (45 chromosomes). Affected females are short, sterile, with undeveloped secondary sexual characteristics.
Q178. (b) First life forms were anaerobic heterotrophs — Earth’s early atmosphere lacked O₂, and organic molecules were available in primordial soup.
Q179. (b) Colostrum contains IgA antibodies that provide passive immunity to the newborn, protecting against infections.
Q180. (b) Oogenesis: one primary oocyte produces one functional ovum and three non-functional polar bodies (unequal division of cytoplasm).
Q181. (b) Interferons are antiviral proteins that don’t kill viruses directly but signal neighbouring uninfected cells to produce antiviral proteins.
Q182. (c) Loop of Henle creates an osmotic gradient in the medulla through the countercurrent mechanism, essential for concentrating urine.
Q183. (b) During contraction: I-band (light band) and H-zone shorten as actin slides over myosin. A-band remains unchanged.
Q184. (b) Optic nerve (cranial nerve II) carries visual information from the retina to the brain (visual cortex).
Q185. (b) Addison’s disease: hyposecretion of adrenal cortex hormones (cortisol, aldosterone). Symptoms: weakness, low BP, hyperpigmentation.
Q186. (b) Placenta forms by interdigitation of chorionic villi (foetal) with uterine endometrium (decidua/maternal). It facilitates nutrient/gas exchange.
Q187. (b) Syphilis (Treponema pallidum) and gonorrhoea (Neisseria gonorrhoeae) are sexually transmitted bacterial diseases.
Q188. (b) Industrial melanism: dark-coloured moths were selected by predators (birds) in polluted areas — a classic example of natural selection.
Q189. (b) Widal test detects antibodies against Salmonella typhi (causative agent of typhoid fever) in patient serum.
Q190. (a) Cnidarians (jellyfish, corals, Hydra) possess nematocysts (stinging cells) on their tentacles for defence and capturing prey.
Q191. (b) Trypsin is a proteolytic enzyme that digests proteins into peptides. It works in alkaline pH of the small intestine.
Q192. (b) Bohr effect: increased CO₂ (low pH) decreases haemoglobin’s affinity for O₂, promoting O₂ release in active tissues.
Q193. (b) Erythropoietin (EPO) is primarily produced by the kidneys in response to hypoxia (low O₂). It stimulates RBC production.
Q194. (c) Acetylcholine is the neurotransmitter at the neuromuscular junction, binding to receptors on muscle fibres to initiate contraction.
Q195. (b) Gigantism occurs due to GH excess during childhood (before epiphyseal closure). In adults, it causes acromegaly instead.
Q196. (b) Adaptive radiation: diversification of a species into many new forms adapted to different niches. E.g., Darwin’s finches, marsupials in Australia.
Q197. (b) Rheumatoid arthritis is an autoimmune disease where the immune system attacks the synovial membrane of joints.
Q198. (b) The vertebral column (backbone) encloses and protects the spinal cord within the vertebral canal.
Q199. (b) Corpus luteum secretes progesterone (and some estrogen) to maintain the endometrium and support early pregnancy.
Q200. (b) Darwin’s finches on Galapagos Islands evolved different beak shapes from a common ancestor — a classic example of adaptive radiation.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top