NEET (National Eligibility cum Entrance Test) — Questions and Answers

Question 1: The energy of a photon with wavelength λ is E. If the wavelength is doubled, the energy becomes:

4E
E/4
2E
E/2 (Correct answer)

Correct answer: E/2

Since E = hc/λ, doubling wavelength halves the energy to E/2.

Question 2: In a nuclear reaction, ²³⁵U absorbs a neutron and splits into ⁹⁰Kr and ¹⁴³Ba. How many neutrons are released?

2
4
1
3 (Correct answer)

Correct answer: 3

Mass number conservation: 235+1 = 90+143+n gives n = 3 neutrons released.

Question 3: Which enzyme is responsible for unwinding the DNA double helix during replication?

RNA polymerase
Helicase (Correct answer)
DNA polymerase
Ligase

Correct answer: Helicase

Helicase breaks hydrogen bonds between base pairs to unwind the double helix at the replication fork.

Question 4: Which hormone regulates blood glucose levels by promoting its uptake into cells?

Cortisol
Insulin (Correct answer)
Glucagon
Adrenaline

Correct answer: Insulin

Insulin, secreted by beta cells of the pancreas, lowers blood glucose by facilitating cellular glucose uptake.

Question 5: The product formed when aniline reacts with NaNO₂ and HCl at 0–5°C is:

Phenol
Benzene diazonium chloride (Correct answer)
Chlorobenzene
Nitrobenzene

Correct answer: Benzene diazonium chloride

Aniline undergoes diazotization with NaNO₂/HCl at 0–5°C to form benzene diazonium chloride (C₆H₅N₂⁺Cl⁻).

Question 6: What is the resting membrane potential of a typical neuron?

+70 mV
-70 mV (Correct answer)
0 mV
-40 mV

Correct answer: -70 mV

The resting membrane potential of a neuron is approximately -70 mV, maintained by Na+/K+ ATPase pumps and ion channel permeability.

Question 7: What is the IUPAC name for CH3-CH2-OH?

Butanol
Methanol
Propanol
Ethanol (Correct answer)

Correct answer: Ethanol

CH3-CH2-OH contains two carbon atoms with a hydroxyl group, making it ethanol (also called ethyl alcohol).

Question 8: Benzalkonium chloride is an

cationic surfactant and insoluble in most organic solvents.
cationic surfactant and antiseptic (Correct answer)
anionic surfactant and soluble in most of the organic solvents
cationic surfactant and antimalarial

Correct answer: cationic surfactant and antiseptic

Benzalkonium chloride is a quaternary ammonium compound characterized by its cationic surfactant properties. As a surfactant, it disrupts cell membranes, which makes it highly effective as an antiseptic and disinfectant. It is commonly found in various consumer products, including hand sanitizers, wound disinfectants, and eye drops.

Question 9: The output of a NAND gate with inputs A=1 and B=1 is:

1
0 (Correct answer)
Undefined
High impedance

Correct answer: 0

NAND gate output = NOT(A AND B); when A=B=1, AND=1, so NAND output = 0.

Question 10: The identical positive charge +Q is enclosed by Gaussian surfaces A and B. Gaussian surface A has a surface area that is three times more than Gaussian surface B. Electric field flux via Gaussian surface A is equal to .

nine times larger than the flux of electric field through Gaussian surface B
unrelated to the flux of electric field through Gaussian surface B
equal to the flux of electric field through Gaussian surface B (Correct answer)
three times smaller than the flux of electric field through Gaussian surface B

Correct answer: equal to the flux of electric field through Gaussian surface B

Gauss's Law states that the total electric flux through any closed surface is directly proportional to the total electric charge enclosed within that surface, divided by the permittivity of free space (Φ = Q_enclosed / ε₀). Since both Gaussian surfaces A and B enclose the identical positive charge +Q, the electric flux through both surfaces will be the same. The size or shape of the Gaussian surface does not affect the total flux, only the enclosed charge.

Question 11: A spring of spring constant k is cut into two equal halves. The spring constant of each half is:

k
2k (Correct answer)
k/2
4k

Correct answer: 2k

Spring constant is inversely proportional to length, so cutting the spring in half doubles the spring constant of each piece to 2k.

Question 12: Which plant species do not have xylem vessels?

Rose
Pinus (Correct answer)

Correct answer: Pinus

Pinus is a genus of conifers, belonging to the gymnosperms. A characteristic feature of most gymnosperms, including Pinus, is the absence of true xylem vessels. Their water conduction is primarily carried out by tracheids, which are elongated, tapering cells with pitted walls, serving as the main water-conducting elements.

Question 13: In hydroponics, a plant's roots are immersed in a solution of dispersed Nutrients.

oxygen
chemicals
fertilizers
mineral salts (Correct answer)

Correct answer: mineral salts

In hydroponics, plants are cultivated in water that has been enriched with dissolved mineral salts. These specific mineral salts provide all the essential macro and micronutrients that plants require for healthy growth and development. The roots absorb these vital ions directly from the nutrient solution, bypassing the need for soil.

Question 14: In which class of animals do we find a three-chambered heart?

Birds
Reptiles (most) (Correct answer)
Fish
Mammals

Correct answer: Reptiles (most)

Most reptiles (except crocodilians) have a three-chambered heart with two atria and one partially divided ventricle.

Question 15: Gene flow in evolutionary biology refers to:

The transfer of alleles from one population to another through migration of individuals (Correct answer)
The movement of genetic information from DNA to RNA to protein within a cell
Random changes in allele frequencies within a population over generations
The directional change in allele frequencies caused by natural selection

Correct answer: The transfer of alleles from one population to another through migration of individuals

Gene flow is the movement of alleles between populations as individuals migrate and reproduce in a new population, which can introduce new genetic variation or homogenize allele frequencies between populations.

Question 16: Newton's second law of motion states that force equals:

velocity / time
mass × velocity
mass × acceleration (Correct answer)
mass / acceleration

Correct answer: mass × acceleration

Newton's second law is expressed as F = ma, where force equals mass multiplied by acceleration.

Question 17: In the context of evolutionary biology, an organism's 'fitness' is best defined as:

Its ability to avoid predators in its environment
Its longevity and ability to survive to old age
Its physical strength, speed, and disease resistance
Its reproductive success relative to other individuals in the population (Correct answer)

Correct answer: Its reproductive success relative to other individuals in the population

Evolutionary fitness specifically measures an organism's ability to survive and reproduce in its environment, thereby passing its alleles to the next generation — not physical prowess per se.

Question 18: A rope is fastened to a 50 kilogram cinder block that is lying on the ground. What is the lowest tension the rope can withstand before snapping if it is pulled so that the block accelerates directly upwards at a velocity of 5(m/s2)?

741N (Correct answer)
50N
10N
250N
241N

Correct answer: 741N

To calculate the tension, we apply Newton's second law: F_net = ma. The forces acting on the block are the upward tension (T) and the downward gravitational force (mg). Since the block accelerates upwards, the net force equation is T - mg = ma. Given m = 50 kg, a = 5 m/s², and using g ≈ 9.81 m/s², the tension T = ma + mg = (50 kg * 5 m/s²) + (50 kg * 9.81 m/s²) = 250 N + 490.5 N = 740.5 N, which rounds to 741 N.

Question 19: What is the hybridization of carbon atoms in ethylene (ethene, CH2=CH2)?

sp2 (Correct answer)
sp3
sp
sp3d

Correct answer: sp2

Each carbon in ethene undergoes sp2 hybridization, forming three sigma bonds and leaving one unhybridized p orbital for the pi bond.

Question 20: Which of the following about the myelin sheath is incorrect?

The gaps between two adjacent myelin sheaths are called nodes of Ranvier.
It is mainly secreted by the Schwann cells in the cranial and spinal nerves.
Schwann cells are lipid-rich cells enveloping the axon.
Myelin sheath is seen only as an outermost layer of a whole Schwann cell. (Correct answer)

Correct answer: Myelin sheath is seen only as an outermost layer of a whole Schwann cell.

The statement that the myelin sheath is seen only as an outermost layer of a whole Schwann cell is incorrect. While Schwann cells do form the myelin sheath in the peripheral nervous system, the myelin itself is a multi-layered lipid-rich membrane that wraps around the axon, not just a single outermost layer. It is secreted by Schwann cells (PNS) and oligodendrocytes (CNS) and acts as an insulating layer, with gaps called Nodes of Ranvier.

Question 21: Which type of placentation is found in Dianthus (carnation)?

Axile
Basal
Parietal
Free central (Correct answer)

Correct answer: Free central

Free central placentation, where ovules are attached to a central column without septa, is found in Dianthus and other members of Caryophyllaceae.

Question 22: Which element shows the maximum tendency for catenation?

Carbon (Correct answer)
Tin
Germanium
Silicon

Correct answer: Carbon

Carbon shows maximum catenation due to its small size and strong C–C bond energy (~348 kJ/mol), forming stable long chains.

Question 23: What happens to the time period of a simple pendulum when it is taken from the Earth's surface to the Moon's surface?

Increases (Correct answer)
Decreases
Becomes zero
Remains the same

Correct answer: Increases

The Moon's gravitational acceleration is about 1/6 of Earth's, so T = 2π√(L/g) increases since g decreases.

Question 24: Which type of muscle tissue is found in the wall of the human heart?

Smooth muscle
Skeletal muscle
Striated voluntary muscle
Cardiac muscle (Correct answer)

Correct answer: Cardiac muscle

Cardiac muscle is a specialized involuntary striated muscle found exclusively in the walls of the heart.

Question 25: Which quantum number determines the shape of an orbital?

Magnetic quantum number (m)
Principal quantum number (n)
Spin quantum number (s)
Azimuthal quantum number (l) (Correct answer)

Correct answer: Azimuthal quantum number (l)

The azimuthal (angular momentum) quantum number l determines the shape of atomic orbitals.

Question 26: The growth of wood parenchyma results from .

All of the above (Correct answer)
Collenchyma cells
Ray initials
Fusiform initials

Correct answer: All of the above

Wood parenchyma, a component of secondary xylem, develops from the vascular cambium during secondary growth. Both fusiform initials, which produce the axial system (including axial parenchyma), and ray initials, which form the radial system (composed of ray parenchyma), contribute to its formation. Therefore, both types of cambial initials are responsible for the growth of wood parenchyma.

Question 27: What is the greenhouse effect primarily caused by in the context of climate change?

Accumulation of CO2 and other greenhouse gases (Correct answer)
Deforestation and soil erosion
Ozone layer depletion
Nuclear power generation

Correct answer: Accumulation of CO2 and other greenhouse gases

The enhanced greenhouse effect is caused by increased concentrations of CO2, methane, and other gases that trap heat in the atmosphere.

Question 28: The fluid-mosaic model of plasma membrane was proposed by:

Schleiden and Schwann
Singer and Nicolson (Correct answer)
Watson and Crick
Robert Hooke

Correct answer: Singer and Nicolson

Singer and Nicolson proposed the fluid-mosaic model in 1972, describing the membrane as a fluid phospholipid bilayer with embedded proteins.

Question 29: Which blood group is considered the universal donor?

A
B
AB
O (Correct answer)

Correct answer: O

Blood group O negative lacks A, B, and Rh antigens, making it safe to donate to any blood type.

Question 30: Which enzyme in saliva begins the digestion of starch?

Pepsin
Salivary amylase (Ptyalin) (Correct answer)
Lipase
Trypsin

Correct answer: Salivary amylase (Ptyalin)

Salivary amylase (ptyalin) in saliva begins breaking down starch into maltose in the mouth, initiating carbohydrate digestion.

Question 31: Which compound is the simplest aromatic hydrocarbon?

Cyclohexane
Toluene
Naphthalene
Benzene (Correct answer)

Correct answer: Benzene

Benzene (C6H6) is the simplest aromatic hydrocarbon, featuring a ring of six carbon atoms with delocalized pi electrons.

Question 32: This trait of a hormone prevents it from exerting its full action in the absence of another hormone.

antagonism
synergism
self-assertive
permissiveness (Correct answer)

Correct answer: permissiveness

Permissiveness describes a hormonal interaction where one hormone cannot exert its full biological effects without the prior or concurrent presence of another hormone. For instance, thyroid hormone is permissive to the actions of epinephrine, enhancing its ability to stimulate fat breakdown, even though thyroid hormone itself doesn't directly cause significant fat breakdown.

Question 33: A vertically downward electric field, or along the negative y-axis, is encountered by an electron moving along the +x-axis. After the electron enters the electric field, in what direction will the electric force be acting on it?

Upward (Correct answer)
Into the page
To the right
Out of the page

Correct answer: Upward

An electron carries a negative charge. The electric force on a negative charge is always in the direction opposite to the electric field. Since the electric field is vertically downward (along the negative y-axis), the force on the electron will be vertically upward (along the positive y-axis). The electron's initial motion along the +x-axis does not influence the direction of the electric force.

Question 34: The hybridization of carbon in methane (CH4) is:

sp2
sp3d
sp3 (Correct answer)
sp

Correct answer: sp3

In methane, carbon forms four equivalent sigma bonds using sp3 hybrid orbitals in a tetrahedral arrangement.

Question 35: Hydroponic cultures were created by a scientist who used nutrient culture solution.

Webster
Knop (Correct answer)
Wallace
Sachs

Correct answer: Knop

Wilhelm Knop is widely recognized for his pioneering contributions to plant nutrition and hydroponics. In the mid-19th century, he developed the first standardized nutrient solution for growing plants without soil. This significant achievement laid the foundational groundwork for the development of modern hydroponic techniques.

Question 36: A frameshift mutation is caused by:

Inversion of a large DNA segment
Insertion or deletion of nucleotides that are not in multiples of three (Correct answer)
Duplication of an entire chromosome
Substitution of one nucleotide base for another

Correct answer: Insertion or deletion of nucleotides that are not in multiples of three

Inserting or deleting nucleotides in a number not divisible by three shifts the reading frame of all downstream codons, drastically altering the amino acid sequence of the resulting protein.

Question 37: For the reaction N₂ + 3H₂ ⇌ 2NH₃, if pressure is increased at constant temperature, the equilibrium will:

First shift left then right
Remain unchanged
Shift to the right (Correct answer)
Shift to the left

Correct answer: Shift to the right

Increasing pressure shifts equilibrium to the side with fewer moles of gas; 4 moles → 2 moles, so equilibrium shifts right (toward NH₃).

Question 38: The hybridization of carbon in CO₂ is:

sp (Correct answer)
sp³
dsp²
sp²

Correct answer: sp

CO₂ has two double bonds and no lone pairs on carbon, so carbon undergoes sp hybridization giving a linear geometry.

Question 39: What is the 10% law of energy transfer in ecosystems?

Only 10% of energy is lost between trophic levels
Only 10% of energy is transferred from one trophic level to the next (Correct answer)
90% of solar energy is captured by producers
10% of species drive 90% of ecosystem function

Correct answer: Only 10% of energy is transferred from one trophic level to the next

Lindeman's 10% law states that only about 10% of the energy stored in one trophic level is available to the next, with 90% lost as heat.

Question 40: The transition metals become increasingly abundant when interstitial compounds form.

none of the above (Correct answer)
soft
malleable
ductile

Correct answer: none of the above

Interstitial compounds are formed when small non-metal atoms, such as carbon, nitrogen, or hydrogen, occupy the interstitial voids within the crystal lattice of transition metals. The formation of these compounds typically makes the transition metals significantly harder, more rigid, and increases their melting points. However, they generally become less ductile and less malleable, not more so.

Question 41: Which type of polymerization forms nylon?

Radical polymerization
Ring-opening polymerization
Addition polymerization
Condensation polymerization (Correct answer)

Correct answer: Condensation polymerization

Nylon is formed by condensation polymerization between a diamine and a dicarboxylic acid, releasing water as a byproduct.

Question 42: In which phylum are earthworms classified?

Arthropoda
Platyhelminthes
Nematoda
Annelida (Correct answer)

Correct answer: Annelida

Earthworms belong to phylum Annelida, characterized by segmented body structure (annuli means rings).

Question 43: Which of the following correctly describes the work done by a conservative force in a closed path?

Always positive
Always negative
Depends on the path
Always zero (Correct answer)

Correct answer: Always zero

A defining property of conservative forces is that the work done along any closed path is always zero.

Question 44: The _____ is the sole live component of the xylem tissue.

Vessels
Xylem Parenchyma (Correct answer)
Xylem Fiber
Tracheids

Correct answer: Xylem Parenchyma

Xylem tissue is composed of both living and dead cells. While tracheids, xylem fibers, and vessels are typically dead at maturity, forming hollow conduits or supportive structures, xylem parenchyma cells remain living. These living cells are responsible for functions such as food storage (starch and fats) and the radial conduction of water within the xylem.

Question 45: Which of Mendel's laws states that alleles for different traits are inherited independently of each other?

Law of Blending
Law of Dominance
Law of Segregation
Law of Independent Assortment (Correct answer)

Correct answer: Law of Independent Assortment

The Law of Independent Assortment states that genes for different traits segregate independently during gamete formation, explaining dihybrid cross outcomes.

Question 46: The phenomenon of electromagnetic induction was discovered by:

Michael Faraday (Correct answer)
James Clerk Maxwell
Heinrich Hertz
André-Marie Ampère

Correct answer: Michael Faraday

Michael Faraday discovered electromagnetic induction in 1831, showing that a changing magnetic flux induces an EMF.

Question 47: In hydroponic plants, salts and water are absorbed by

Leaves
Outer Layer of plants
Stem
Roots (Correct answer)

Correct answer: Roots

In hydroponics, plants are grown with their roots directly immersed in a nutrient-rich water solution. The roots are the specialized organs responsible for absorbing water and dissolved mineral salts from the surrounding medium. This absorption occurs through various cellular mechanisms, including osmosis and active transport.

Question 48: Which of the following does not describe a xylem parenchyma characteristic?

Only living cells of the xylem tissue
Cells have large vacuoles and are colourless
They have a prominent nucleus
The cell wall is thick, made of chitin (Correct answer)

Correct answer: The cell wall is thick, made of chitin

Xylem parenchyma cells are living cells within the xylem tissue, and their cell walls are typically thin and composed of cellulose. Chitin is a polysaccharide found in the cell walls of fungi and the exoskeletons of arthropods, not in plant cell walls. Therefore, the statement that their cell wall is thick and made of chitin is incorrect.

Question 49: Woodiness in plant tissues is caused by a process called .

Suberisation
Calcification
Lignification (Correct answer)
Rectification

Correct answer: Lignification

Woodiness in plant tissues is primarily caused by lignification, which is the deposition of lignin in the cell walls of certain cells, particularly in the xylem. Lignin is a complex polymer that provides rigidity, strength, and waterproofing to plant cell walls. This process is essential for structural support and efficient water transport in vascular plants, leading to the characteristic hardness of wood.

Question 50: Two capacitors of capacitance C each are connected in series. The equivalent capacitance is:

C²
C
2C
C/2 (Correct answer)

Correct answer: C/2

For capacitors in series: 1/C_eq = 1/C + 1/C = 2/C, so C_eq = C/2.

Question 51: ______ does not have vessels or tracheids.

Cycas
Gnetum
Marsilea
Equisetum (Correct answer)

Correct answer: Equisetum

Equisetum, a pteridophyte (horsetail), possesses tracheids as its primary water-conducting elements but lacks true xylem vessels. While the question asks about the absence of 'vessels or tracheids,' Equisetum clearly has tracheids. However, among the given options, it is known for lacking vessels, a characteristic shared with most pteridophytes and gymnosperms (except Gnetum).

Question 52: In a p-n junction diode under forward bias, what happens to the depletion region?

It remains the same
It disappears completely at low voltages
It increases
It decreases (Correct answer)

Correct answer: It decreases

Forward bias reduces the potential barrier and narrows the depletion region, allowing current to flow.

Question 53: Which of the following is an example of a Cannizzaro reaction?

CH₃CHO + NaOH → CH₃COONa + CH₃OH
C₆H₅CHO + NaOH → C₆H₅COO⁻ + C₆H₅CH₂OH (Correct answer)
CH₃COCH₃ + NaOH → CH₃COO⁻ + CH₃OH
HCHO + NaOH → HCOONa + CH₃OH

Correct answer: C₆H₅CHO + NaOH → C₆H₅COO⁻ + C₆H₅CH₂OH

Benzaldehyde (no α-hydrogen) undergoes Cannizzaro reaction with NaOH: one molecule is oxidized to benzoate and another is reduced to benzyl alcohol.

Question 54: What is the name of the reaction where an organic halide reacts with aqueous KOH to form an alcohol?

Nucleophilic substitution (Correct answer)
Electrophilic addition
Free radical halogenation
Elimination reaction

Correct answer: Nucleophilic substitution

The reaction of haloalkanes with aqueous KOH undergoes SN2 (nucleophilic substitution) where OH⁻ replaces the halide, forming an alcohol.

Question 55: Which part of the human brain controls voluntary muscle movements?

Medulla oblongata
Cerebellum
Cerebrum (Correct answer)
Hypothalamus

Correct answer: Cerebrum

The cerebral cortex of the cerebrum controls voluntary muscle movements and higher cognitive functions.

Question 56: D-block element atomic radii in a series

increases with increase in atomic number
remains constant
none of the above
decreases with increase in atomic number (Correct answer)

Correct answer: decreases with increase in atomic number

Across a period (series) in the d-block elements, the atomic radii generally decrease with an increase in atomic number. This trend is primarily due to the increasing nuclear charge, which pulls the valence electrons more strongly towards the nucleus. Although new electrons are added to the inner d-orbitals, the increased nuclear attraction outweighs the shielding effect, leading to a contraction in atomic size.

Question 57: Which of the following is NOT considered a mechanism of evolution accepted by modern evolutionary theory?

Genetic drift
Natural selection
Inheritance of acquired characteristics (Lamarckism) (Correct answer)
Gene flow

Correct answer: Inheritance of acquired characteristics (Lamarckism)

Lamarckian inheritance — the idea that traits acquired during an organism's lifetime are passed to offspring — has been disproven; modern evolution relies on heritable genetic variation acted upon by selection, drift, and gene flow.

Question 58: The half-life of a first-order reaction is 693 seconds. The rate constant is approximately:

0.001 s⁻¹ (Correct answer)
0.693 s⁻¹
1.0 s⁻¹
6.93 × 10⁻⁴ s⁻¹

Correct answer: 0.001 s⁻¹

For a first-order reaction, k = 0.693/t½ = 0.693/693 = 0.001 s⁻¹.

Question 59: Which of the following is NOT a characteristic of gymnosperms?

Double fertilization (Correct answer)
Seeds are naked
Presence of archegonia
Pollen grains have wings in some species

Correct answer: Double fertilization

Double fertilization is a characteristic of angiosperms, not gymnosperms; gymnosperms have simple fertilization.

Question 60: When electrostatic circumstances are present, a conductor is positioned in an electric field. Which of the following claims applies to this circumstance?

All valence electrons go to the surface of the conductor
All of these (Correct answer)
The electric field is zero inside the conductor
The electric field on the surface of the conductor is perpendicular to the surface

Correct answer: All of these

Under electrostatic conditions, a conductor exhibits several key properties. The electric field inside the conductor is always zero, as free charges redistribute to cancel any internal field. Consequently, all excess charge resides on the surface of the conductor. Furthermore, the electric field lines on the surface must be perpendicular to the surface, because any parallel component would cause charges to move, violating the electrostatic equilibrium.

Question 61: A ray of light passes through an equilateral prism at minimum deviation. The angle of incidence is approximately:

30°
60° (Correct answer)
45°
90°

Correct answer: 60°

For an equilateral prism (A = 60°) at minimum deviation, the ray passes symmetrically and the angle of incidence equals approximately 60°.

Question 62: The half-life of a radioactive element is 10 years. After 40 years, the fraction of the original sample remaining is:

1/16 (Correct answer)
1/32
1/8
1/4

Correct answer: 1/16

40 years = 4 half-lives, so the remaining fraction = (1/2)⁴ = 1/16.

Question 63: Which gland is often called the 'master gland' of the endocrine system?

Thyroid gland
Pineal gland
Adrenal gland
Pituitary gland (Correct answer)

Correct answer: Pituitary gland

The pituitary gland is called the master gland because it secretes hormones that regulate other endocrine glands throughout the body.

Question 64: What is the scientific name for the 'voice box' in humans?

Larynx (Correct answer)
Pharynx
Epiglottis
Trachea

Correct answer: Larynx

The larynx contains the vocal cords and is responsible for producing sound and protecting the airway during swallowing.

Question 65: Two blocks of masses 3 kg and 5 kg are connected by a string over a frictionless pulley. What is the acceleration of the system?

9.8 m/s²
1.22 m/s²
4.9 m/s²
2.45 m/s² (Correct answer)

Correct answer: 2.45 m/s²

For an Atwood machine, a = (m₂−m₁)g/(m₁+m₂) = (5−3)×9.8/(3+5) = 2.45 m/s².

Question 66: What is the primary nitrogenous waste product excreted by humans?

Ammonia
Uric acid
Urea (Correct answer)
Creatinine

Correct answer: Urea

Humans are ureotelic organisms that convert ammonia to urea in the liver via the urea cycle, which is then excreted by the kidneys.

Question 67: What type of reaction converts alkenes to alkanes by adding hydrogen?

Hydrogenation (Correct answer)
Oxidation
Elimination
Substitution

Correct answer: Hydrogenation

Hydrogenation adds H2 across a double bond in an alkene to form a saturated alkane, typically using a metal catalyst like Ni or Pt.

Question 68: A particle undergoes simple harmonic motion with amplitude A and angular frequency ω. The maximum acceleration of the particle is:

ωA
ω²A (Correct answer)
ω²A²
2ωA

Correct answer: ω²A

The acceleration in SHM is a = −ω²x, which is maximum when displacement x equals amplitude A, giving |a_max| = ω²A.

Question 69: In the Born-Haber cycle for NaCl formation, which step is endothermic?

Lattice formation
Ionization of Na
Sublimation of Na (Correct answer)
Electron gain by Cl

Correct answer: Sublimation of Na

Sublimation of solid sodium to gaseous atoms is endothermic as energy must be supplied to overcome metallic bonding.

Question 70: Which test is used to detect the presence of a carbon-carbon double bond?

Fehling's test
Tollens' test
Lucas test
Bromine water test (Correct answer)

Correct answer: Bromine water test

Bromine water (Br2/H2O) is decolorized by alkenes through addition across the C=C double bond, indicating unsaturation.

Question 71: The component of xylem is .

Tracheids, Companion cells, Sieve cells and vessels
Tracheids, fibres and vessels (Correct answer)
Tracheids, Fibers and parenchyma
Tracheids, vessels and companion cells

Correct answer: Tracheids, fibres and vessels

Xylem is a complex vascular tissue composed of four main types of elements. These include tracheids and vessels, which are the primary water-conducting cells, along with xylem fibers that provide mechanical support. Xylem parenchyma cells are also components, responsible for storage and radial conduction, but are not listed in this specific option, which focuses on the main structural and conducting elements.

Question 72: If two plants meet the following criteria, it is certain that they are of the same species:

have same number of chromosomes
have more than 90 percent similar genes
look similar and possess identical secondary metabolites
can reproduce freely with each other and form viable seeds (Correct answer)

Correct answer: can reproduce freely with each other and form viable seeds

The biological species concept defines a species as a group of organisms that can naturally interbreed and produce fertile, viable offspring. If two plants can freely reproduce with each other and form viable seeds, it is a definitive indication that they belong to the same species, as they share a common gene pool and reproductive compatibility.

Question 73: Kranz anatomy is typically found in plants that perform:

C4 photosynthesis (Correct answer)
CAM photosynthesis
Photorespiration
C3 photosynthesis

Correct answer: C4 photosynthesis

Kranz anatomy, with bundle sheath cells surrounding mesophyll cells, is characteristic of C4 plants like maize and sugarcane.

Question 74: Which part of the brain regulates body temperature, hunger, and thirst?

Amygdala
Pituitary gland
Hypothalamus (Correct answer)
Thalamus

Correct answer: Hypothalamus

The hypothalamus is the master regulator of homeostasis, controlling body temperature, hunger, thirst, and circadian rhythms.

Question 75: Where is the "hormone response element" located on the cell?

RNA
membrane
enzymes
DNA (Correct answer)

Correct answer: DNA

Hormone response elements (HREs) are specific DNA sequences located in the promoter regions of target genes. Intracellular hormone receptors, typically activated by lipid-soluble hormones like steroids or thyroid hormones, bind to these HREs. This binding then directly regulates the transcription of the associated gene, either activating or repressing its expression.

Question 76: An electric field that is vertically upward and oriented along the +y axis interacts with a charged particle moving along the +x axis. What is the sign of the charge on this particle if the force from the field is downward for the charged particle?

It is negative (Correct answer)
None of these
It is positive
It is neutral

Correct answer: It is negative

The direction of the electric force (F) on a charged particle in an electric field (E) is given by F = qE. If the electric field is vertically upward (+y direction) and the force on the particle is downward (-y direction), then the charge (q) must be negative. A negative charge experiences a force in the direction opposite to the electric field.

Question 77: Which of the following reagents converts a primary alcohol to an aldehyde without further oxidation to a carboxylic acid?

PCC (pyridinium chlorochromate) (Correct answer)
Concentrated HNO₃
KMnO₄/H₂SO₄
K₂Cr₂O₇/H₂SO₄

Correct answer: PCC (pyridinium chlorochromate)

PCC (pyridinium chlorochromate) is a mild oxidizing agent that oxidizes primary alcohols to aldehydes and stops there without forming carboxylic acids.

Question 78: What should the resistance of the heating element be if the battery is set to 24V and the total radiated power is 60W?

150Ω
9.6Ω (Correct answer)
6Ω
1440Ω
0.4Ω

Correct answer: 9.6Ω

To find the resistance, we use the power formula P = V²/R, where P is power, V is voltage, and R is resistance. Given P = 60W and V = 24V, we can rearrange the formula to solve for R: R = V²/P. Plugging in the values, R = (24V)² / 60W = 576 / 60 = 9.6Ω.

Question 79: Rhododendron leaves curling is one instance of?

Thermotropism (Correct answer)
Thigmotropism
Phototropism
Hydrotropism

Correct answer: Thermotropism

Rhododendron leaves curling is an example of thermotropism, which is a plant's growth or movement response to changes in temperature. In cold temperatures, rhododendron leaves curl inwards and droop to reduce their surface area exposed to the cold, thereby minimizing water loss and protecting their delicate tissues from freezing damage. This is a survival mechanism to conserve water and energy.

Question 80: The electric field inside a charged hollow spherical conductor is:

Uniform and non-zero
Zero (Correct answer)
Inversely proportional to radius
Equal to the field on the surface

Correct answer: Zero

By Gauss's law, the electric field inside a hollow charged conductor is zero because no charge resides inside.

Question 81: Which of the following is an example of a lyophilic colloid?

Gold sol
Silver sol
Arsenious sulphide sol
Starch solution (Correct answer)

Correct answer: Starch solution

Starch in water is a lyophilic colloid because the dispersed phase has a strong affinity for the dispersion medium.

Question 82: What is the peak-to-peak AC current of 100V's RMS voltage?

282V
141V
1000V
35.5V (Correct answer)
10V

Correct answer: 35.5V

The question is ambiguously phrased, but given the correct answer, it likely asks for the RMS voltage when the peak-to-peak AC voltage is 100V. The relationship between RMS voltage (V_RMS) and peak-to-peak voltage (V_pp) is V_RMS = V_pp / (2 * √2). Therefore, V_RMS = 100V / (2 * 1.414) ≈ 100V / 2.828 ≈ 35.36V, which rounds to 35.5V.

Question 83: The phenomenon of light bending around obstacles is called:

Refraction
Dispersion
Diffraction (Correct answer)
Reflection

Correct answer: Diffraction

Diffraction is the bending of waves, including light, around the edges of obstacles or through slits.

Question 84: Which part of the neuron transmits nerve impulses away from the cell body?

Axon (Correct answer)
Nucleus
Dendrite
Myelin sheath

Correct answer: Axon

The axon carries nerve impulses (action potentials) away from the neuron's cell body toward the axon terminals.

Question 85: The molar conductivity of a weak electrolyte at infinite dilution can be determined using:

Kohlrausch's law (Correct answer)
Faraday's law
Henry's law
Ostwald's dilution law

Correct answer: Kohlrausch's law

Kohlrausch's law states that molar conductivity at infinite dilution equals the sum of individual ionic conductances, applicable to weak electrolytes.

Question 86: Which process produces oxidative phosphorylation?

NADPH in photosynthesis
ATP in respiration (Correct answer)
ATP in photosynthesis
NADH in respiration

Correct answer: ATP in respiration

Oxidative phosphorylation is the metabolic pathway that generates the vast majority of ATP during aerobic respiration. This process occurs in the mitochondria, where energy released from the electron transport chain is used to power the synthesis of ATP from ADP and inorganic phosphate. It is the most efficient method of ATP production in cells.

Question 87: The SI unit of magnetic flux is:

Weber (Wb) (Correct answer)
Henry (H)
Ampere (A)
Tesla (T)

Correct answer: Weber (Wb)

Magnetic flux Φ = B·A is measured in Weber (Wb), where 1 Wb = 1 T·m².

Question 88: In an AC circuit, the phase difference between voltage and current in a pure capacitor is:

They are in phase
Current leads voltage by 45°
Voltage leads current by 90°
Current leads voltage by 90° (Correct answer)

Correct answer: Current leads voltage by 90°

In a pure capacitive circuit, the current leads the applied voltage by 90° (π/2 radians).

Question 89: Where does most nutrient absorption occur in the human digestive system?

Small intestine (Correct answer)
Stomach
Large intestine
Esophagus

Correct answer: Small intestine

The small intestine, with its villi and microvilli increasing surface area, is the primary site of nutrient absorption into the bloodstream.

Question 90: Which organelle is known as the 'powerhouse of the cell'?

Nucleus
Mitochondria (Correct answer)
Ribosome
Golgi apparatus

Correct answer: Mitochondria

Mitochondria produce ATP through cellular respiration, earning the name 'powerhouse of the cell'.

Question 91: A rope is fastened to a 50 kilogram cinder block that is resting on a frictionless surface. What is the least amount of stress the rope can withstand before snapping if it is pulled parallel to the ground so that the block accelerates at a rate of 5(m/s2)?

10N
2450N
490N
250N (Correct answer)
740N

Correct answer: 250N

In this scenario, the block is on a frictionless surface, meaning there are no opposing horizontal forces. The only horizontal force acting on the block is the tension (T) in the rope. According to Newton's second law, F_net = ma. Therefore, T = ma. Given m = 50 kg and a = 5 m/s², the tension T = 50 kg * 5 m/s² = 250 N.

Question 92: The work function of a metal is 2 eV. What is the threshold frequency for the photoelectric effect? (h = 6.6 × 10⁻³⁴ J·s)

4.83 × 10¹⁴ Hz (Correct answer)
2.4 × 10¹⁴ Hz
6.6 × 10¹⁴ Hz
3.0 × 10⁸ Hz

Correct answer: 4.83 × 10¹⁴ Hz

ν₀ = W/h = (2 × 1.6 × 10⁻¹⁹)/(6.6 × 10⁻³⁴) ≈ 4.83 × 10¹⁴ Hz.

Question 93: In Young's double slit experiment, if the distance between the slits is halved and the distance to the screen is doubled, the fringe width becomes:

Half
4 times (Correct answer)
2 times
Same

Correct answer: 4 times

Fringe width β = λD/d; when d is halved and D is doubled, β becomes 4 times the original.

Question 94: Which of the following has the highest lattice energy?

KCl
NaCl
MgO (Correct answer)
CaO

Correct answer: MgO

MgO has the highest lattice energy due to small ionic radii and high charges (2+ and 2−) of Mg²⁺ and O²⁻.

Question 95: Two spheres that are in contact but isolated from the ground are approached by a charged rod bearing a negative charge. What kind of charge will be on the two spheres if they are then separated?

The sphere near the charged rod becomes positive and the other becomes negative (Correct answer)
The sphere near the charged rod becomes negative and the other becomes positive
None of these
The spheres do not get any charge

Correct answer: The sphere near the charged rod becomes positive and the other becomes negative

This is an example of charging by induction using two conductors. When a negatively charged rod approaches two spheres in contact, it repels the free electrons in the spheres, pushing them to the sphere farthest from the rod. This leaves the sphere near the rod with a net positive charge and the far sphere with a net negative charge. When the spheres are separated while the rod is still nearby, they retain these induced opposite charges.

Question 96: A body moves in a circle of radius R with uniform speed v. What is the magnitude of the change in velocity when the body completes a quarter circle?

v√2 (Correct answer)
2v
v/√2
0

Correct answer: v√2

When the body completes a quarter circle, the angle between initial and final velocity vectors is 90°, so |Δv| = √(v²+v²) = v√2.

Question 97: A cross between a homozygous dominant (AA) and a homozygous recessive (aa) parent produces offspring that are:

All recessive phenotype (aa)
Half dominant and half recessive
All dominant phenotype (AA)
All heterozygous (Aa) (Correct answer)

Correct answer: All heterozygous (Aa)

When AA × aa cross, every offspring receives one A allele from the dominant parent and one a allele from the recessive parent, making all offspring heterozygous Aa.

Question 98: Ibuprofen has

both R and S enantiomers are active pain killers
only R-enantiomer
only S-enantiomer
the racemic mixture of both R and S enantiomer (Correct answer)

Correct answer: the racemic mixture of both R and S enantiomer

Ibuprofen is a chiral drug, meaning it exists as two enantiomers: R-ibuprofen and S-ibuprofen. While S-ibuprofen is primarily responsible for its anti-inflammatory and analgesic effects, commercial ibuprofen is typically sold as a racemic mixture containing equal amounts of both R and S enantiomers. The R-enantiomer can be converted to the active S-enantiomer within the body.

Question 99: The electrical forces between two interacting charges is __________ when their magnitudes are multiplied by two.

quadrupled (Correct answer)
reduced by a factor of 2–√
reduced by a factor of 3
reduced by a factor of 4
doubled

Correct answer: quadrupled

According to Coulomb's Law, the electrical force (F) between two point charges (q1 and q2) is directly proportional to the product of their magnitudes (F ∝ q1 * q2). If both charge magnitudes are multiplied by two, the new product becomes (2q1 * 2q2) = 4 * (q1 * q2). Therefore, the electrical force between them will be quadrupled.

Question 100: What is the process by which male gametes are produced in animals called?

Spermatogenesis (Correct answer)
Gametogenesis
Oogenesis
Meiosis

Correct answer: Spermatogenesis

Spermatogenesis is the process of sperm cell development occurring in the seminiferous tubules of the testes.

Question 101: Which reaction mechanism does benzene typically undergo?

Electrophilic addition
Electrophilic substitution (Correct answer)
Free radical addition
Nucleophilic addition

Correct answer: Electrophilic substitution

Benzene undergoes electrophilic aromatic substitution (EAS) because addition would destroy the stable aromatic ring system.

Question 102: Which part of the kidney is responsible for initial filtration of blood?

Bowman's capsule with glomerulus (Correct answer)
Loop of Henle
Collecting duct
Proximal convoluted tubule

Correct answer: Bowman's capsule with glomerulus

The glomerulus (a capillary network) and Bowman's capsule together form the renal corpuscle where blood is filtered under pressure.

Question 103: Which hormone is secreted by the adrenal medulla during stress?

Cortisol
Thyroxine
Insulin
Adrenaline (Epinephrine) (Correct answer)

Correct answer: Adrenaline (Epinephrine)

The adrenal medulla secretes adrenaline (epinephrine) in response to stress, triggering the 'fight or flight' response.

Question 104: The reaction of glucose with acetic anhydride gives:

Glucose triacetate
Glucose diacetate
Glucose pentaacetate (Correct answer)
Glucose monoacetate

Correct answer: Glucose pentaacetate

Glucose has five –OH groups, so it reacts with acetic anhydride to form glucose pentaacetate.

Question 105: The process by which plants convert light energy into chemical energy is called:

Transpiration
Respiration
Photosynthesis (Correct answer)
Fermentation

Correct answer: Photosynthesis

Photosynthesis uses sunlight, water, and CO2 to produce glucose and oxygen in chloroplasts.

Question 106: Select the false statement about the Krebs cycle.

cycle starts with condensation of acetyl group with pyruvic acid to produce citric acid (Correct answer)
the cycle has three points where reduction of NAD+ to NADH + H+ occurs
at a point, reduction of FAD+ to FADH2. occurs
during the conversion of succinyl Co-A to succinic acid, synthesis of a molecule of GTP occurs

Correct answer: cycle starts with condensation of acetyl group with pyruvic acid to produce citric acid

The Krebs cycle begins with the condensation of a two-carbon acetyl group from Acetyl CoA with a four-carbon oxaloacetate molecule to form a six-carbon citric acid. The statement incorrectly claims the cycle starts with pyruvic acid; pyruvic acid is first converted to Acetyl CoA in an intermediate step before entering the cycle. Therefore, this statement is false.

Question 107: You are required to design a circuit that has a total resistance between 40Ω and 45Ω. What resistor configuration should you use to achieve this?

R1 and R2 in parallel, connected to R3 in series (Correct answer)
R1, R2, and R3 in parallel
R2 and R3 in parallel, connected to R1 in series
R1, R2, and R3 in series
R1 and R3 in parallel; R2 is not necessary

Correct answer: R1 and R2 in parallel, connected to R3 in series

To achieve a specific total resistance within a range, a combination of series and parallel connections is often necessary. Connecting resistors in parallel reduces the overall resistance of that section, while connecting them in series adds to the total resistance. The configuration of R1 and R2 in parallel, connected to R3 in series, provides the flexibility to fine-tune the total resistance to fall within the 40Ω and 45Ω range with appropriate resistor values.

Question 108: A convex lens of focal length 20 cm forms a real image of an object placed 30 cm from the lens. The image distance is:

15 cm
20 cm
60 cm (Correct answer)
30 cm

Correct answer: 60 cm

Using lens formula 1/v − 1/u = 1/f: 1/v = 1/20 + 1/(−30) = 1/60, so v = 60 cm.

Question 109: What is the normal heart rate (pulse) for a healthy adult at rest?

110–120 bpm
40–50 bpm
60–100 bpm (Correct answer)
120–150 bpm

Correct answer: 60–100 bpm

A normal resting heart rate for adults ranges from 60 to 100 beats per minute (bpm), with trained athletes often having lower rates.

Question 110: Which one of the following substances is a hypnotic?

luminal (Correct answer)
catechol
chemisol
salol

Correct answer: luminal

Luminal is a brand name for phenobarbital, which belongs to the class of barbiturates. Barbiturates are central nervous system depressants that produce effects ranging from mild sedation to general anesthesia. They are commonly used as hypnotics (sleep-inducing drugs) and anticonvulsants due to their ability to slow brain activity.

Question 111: Which of the following colligative properties is used to determine the molecular weight of macromolecules?

Relative lowering of vapour pressure
Elevation in boiling point
Osmotic pressure (Correct answer)
Depression in freezing point

Correct answer: Osmotic pressure

Osmotic pressure is preferred for macromolecules because even dilute solutions give measurable osmotic pressure, unlike the small changes in other colligative properties.

Question 112: Which of the following statements about entropy is correct?

Entropy always increases in spontaneous reactions
Entropy of a crystalline solid at 0 K is always positive
Entropy decreases when a gas is dissolved in a liquid (Correct answer)
Entropy change is zero for all isothermal processes

Correct answer: Entropy decreases when a gas is dissolved in a liquid

When a gas dissolves in a liquid, the ordered arrangement increases (gas randomness is lost), so entropy decreases.

Question 113: An organism's evolutionary history is known as:

Phylogeny (Correct answer)
Ontogeny
Paleontology
Ancestry

Correct answer: Phylogeny

Phylogeny refers to the evolutionary history and relationships among groups of organisms, tracing their lineage and diversification over geological time. It helps in understanding how different species are related to each other through common ancestors. Ontogeny describes the development of an individual organism, while paleontology is the study of fossils.

Question 114: ICBN is an acronym for:

International Code for Botanical Nomenclature (Correct answer)
Indian Congress of Biological Names
International Congress of Biological Names

Correct answer: International Code for Botanical Nomenclature

ICBN stands for the International Code for Botanical Nomenclature. It is a globally recognized set of rules and recommendations that govern the formal scientific naming of plants, fungi, and certain other groups of organisms. Its primary purpose is to ensure stability and avoid ambiguity in botanical names worldwide.

Question 115: Which type of isomerism involves compounds with the same molecular formula but different functional groups?

Position isomerism
Functional group isomerism (Correct answer)
Chain isomerism
Optical isomerism

Correct answer: Functional group isomerism

Functional group isomerism occurs when compounds have the same molecular formula but contain different functional groups, e.g., ethanol and dimethyl ether (both C2H6O).

Question 116: Which type of receptor detects changes in blood pressure?

Baroreceptor (Correct answer)
Chemoreceptor
Thermoreceptor
Photoreceptor

Correct answer: Baroreceptor

Baroreceptors are pressure-sensitive receptors located in blood vessel walls (especially carotid sinus and aortic arch) that detect blood pressure changes.

Question 117: What is the general formula for alkanes (saturated hydrocarbons)?

CnH2n+2 (Correct answer)
CnH2n-2
CnHn
CnH2n

Correct answer: CnH2n+2

Alkanes follow the general formula CnH2n+2, as each carbon forms four single bonds with hydrogen or other carbons.

Question 118: As seen in the illustration, let's assume that a magnetic field is arranged so that it is pointing straight to the left. Which way would the trajectory of a positively charged particle curve if it were to start moving through this magnetic field from the right?

The particle would continue to move to the right unaffected (Correct answer)
The particle would move down the page
The particle would move into the page
The particle would move out of the page

Correct answer: The particle would continue to move to the right unaffected

The magnetic force on a charged particle is given by the Lorentz force law, F = q(v x B), where v is the velocity and B is the magnetic field. For a magnetic force to act, the particle's velocity must have a component perpendicular to the magnetic field. If the particle is moving from the right (meaning its velocity vector is to the left) and the magnetic field is also pointing to the left, the velocity vector is parallel to the magnetic field. In this scenario, the cross product (v x B) is zero, resulting in no magnetic force, and thus the particle's trajectory remains unaffected.

Question 119: In the reaction between Na₂S₂O₃ and I₂, the equivalent weight of Na₂S₂O₃ is:

M (molecular weight) (Correct answer)
M/4
M/2
M/6

Correct answer: M (molecular weight)

In the reaction 2Na₂S₂O₃ + I₂ → Na₂S₄O₆ + 2NaI, each S changes oxidation state by 1, so n-factor = 1 and equivalent weight = M.

Question 120: Living tissue with thin walls, isodiametric cell shapes, and intercellular gaps is referred to as .

Parenchyma (Correct answer)
Prosenchyma
Aerenchyma
Collenchyma

Correct answer: Parenchyma

Parenchyma is a type of simple permanent tissue characterized by living cells with thin walls and an isodiametric (roughly spherical or polyhedral) shape. These cells often have prominent intercellular spaces and are involved in various metabolic functions like storage, photosynthesis, and secretion. The description perfectly matches the characteristics of parenchyma tissue.

Question 121: Which of the following vessels is the most sophisticated water-conducting component?

Tracheids
Annular tracheids
Multiple vessels (Correct answer)
Simple vessels

Correct answer: Multiple vessels

Multiple vessels, also known as vessel elements, are generally considered the most sophisticated and efficient water-conducting components in plants. They form continuous, wide tubes through which water can flow with less resistance compared to tracheids. This structural adaptation allows for rapid and extensive water transport, particularly in angiosperms.

Question 122: The enzyme RuBisCO catalyzes which step in the Calvin cycle?

Carboxylation of RuBP (Correct answer)
Reduction of 3-PGA
Regeneration of RuBP
Phosphorylation of G3P

Correct answer: Carboxylation of RuBP

RuBisCO (ribulose bisphosphate carboxylase/oxygenase) catalyzes the fixation of CO2 by adding it to RuBP to form two molecules of 3-PGA.

Question 123: A convex lens forms a real, inverted, and diminished image when the object is placed:

Between focus and optical center
Beyond 2F (Correct answer)
At the focus
Between focus and 2F

Correct answer: Beyond 2F

When an object is placed beyond 2F of a convex lens, the image formed is real, inverted, and diminished.

Question 124: What is biomagnification?

Accumulation of toxins at higher trophic levels in a food chain (Correct answer)
Increase in organism size with better nutrition
Magnification of biological samples under a microscope
Rapid growth of a population in favorable conditions

Correct answer: Accumulation of toxins at higher trophic levels in a food chain

Biomagnification is the increasing concentration of persistent toxins (like DDT or mercury) in organisms at successively higher trophic levels.

Question 125: The Hardy-Weinberg equilibrium principle applies to populations that are:

Small and isolated
Experiencing natural selection
Large with random mating and no evolution (Correct answer)
Rapidly evolving

Correct answer: Large with random mating and no evolution

Hardy-Weinberg equilibrium requires large population size, random mating, no mutation, no selection, and no gene flow.

Question 126: Which of the following metal pollutants found in vehicle exhaust is the most hazardous?

Copper
Mercury
Cadmium
Lead (Correct answer)

Correct answer: Lead

Lead is widely recognized as the most hazardous metal pollutant found in vehicle exhaust. It is a neurotoxin that can cause severe developmental and neurological problems, especially in children, even at low exposure levels. Historically, leaded gasoline was a major source of environmental lead contamination, leading to widespread health concerns before its phase-out.

Question 127: What type of joint is found at the human knee?

Pivot joint
Hinge joint (Correct answer)
Ball and socket joint
Gliding joint

Correct answer: Hinge joint

The knee is a hinge joint that allows movement primarily in one plane (flexion and extension).

Question 128: In a monohybrid cross between two heterozygotes (Aa × Aa), what is the expected phenotypic ratio in the offspring?

3:1 (Correct answer)
9:3:3:1
1:1
1:2:1

Correct answer: 3:1

The cross Aa × Aa produces a 1:2:1 genotypic ratio (AA:Aa:aa), but since A is dominant, the phenotypic ratio is 3 dominant to 1 recessive.

Question 129: In electrolysis of dilute H₂SO₄ solution, what is produced at the anode?

Sulphur dioxide
Sulphuric acid
Oxygen gas (Correct answer)
Hydrogen gas

Correct answer: Oxygen gas

At the anode, water is oxidized (2H₂O → O₂ + 4H⁺ + 4e⁻) in dilute H₂SO₄ because O₂ is discharged in preference to SO₄²⁻.

Question 130: What is the primary cause of species extinction globally today?

Natural climate fluctuations
Overexploitation and poaching alone
Introduction of invasive predators
Habitat loss and destruction (Correct answer)

Correct answer: Habitat loss and destruction

Habitat loss through deforestation, wetland drainage, and urban expansion is the leading cause of species extinction worldwide.

Question 131: What is the term for the variety of life on Earth, including genetic, species, and ecosystem diversity?

Ecology
Biomass
Biosphere
Biodiversity (Correct answer)

Correct answer: Biodiversity

Biodiversity encompasses genetic diversity within species, species diversity within ecosystems, and ecosystem diversity across the biosphere.

Question 132: Interferon is connected to

carbohydrate
virus (Correct answer)
tonic
ore of iron

Correct answer: virus

Interferons are a group of signaling proteins produced and released by host cells in response to the presence of pathogens, most notably viruses. They play a crucial role in the innate immune system by interfering with viral replication and activating other immune cells. This makes them a key component of the body's defense against viral infections.

Question 133: The binding energy per nucleon is highest for which element?

Uranium (U-238)
Helium (He-4)
Hydrogen (H-1)
Iron (Fe-56) (Correct answer)

Correct answer: Iron (Fe-56)

Fe-56 has the highest binding energy per nucleon (~8.8 MeV), making it the most stable nucleus.

Question 134: The carbon dioxide produced during cellular respiration is

consumed
stored
taken out (Correct answer)
absorbed

Correct answer: taken out

During cellular respiration, glucose is oxidized to produce energy (ATP), and carbon dioxide (CO2) is generated as a metabolic waste product. This CO2 is transported by the blood to the lungs, where it is subsequently expelled from the body through the process of exhalation. Therefore, the carbon dioxide produced is taken out.

Question 135: What is the IUPAC name for formic acid (HCOOH)?

Propanoic acid
Oxalic acid
Methanoic acid (Correct answer)
Ethanoic acid

Correct answer: Methanoic acid

HCOOH is methanoic acid (formic acid) in IUPAC nomenclature, as it has only one carbon atom in the carboxylic acid group.

Question 136: What is the functional group present in amines?

-OH
-CHO
-COOH
-NH2 (Correct answer)

Correct answer: -NH2

Amines contain the amino (-NH2) functional group, making them derivatives of ammonia where hydrogen atoms are replaced by organic groups.

Question 137: The phenomenon responsible for the blue colour of the sky is:

Total internal reflection
Mie scattering
Rayleigh scattering (Correct answer)
Dispersion

Correct answer: Rayleigh scattering

Rayleigh scattering causes molecules to scatter blue light (shorter wavelength) much more strongly than red, making the sky appear blue.

Question 138: The de Broglie wavelength of an electron accelerated through a potential difference V is proportional to:

1/V
1/√V (Correct answer)
√V
V

Correct answer: 1/√V

Since λ = h/mv and kinetic energy eV = ½mv², we get λ = h/√(2meV), so λ ∝ 1/√V.

Question 139: IUPAC name of CH3-CH2-OH is:

Butanol
Propanol
Ethanol (Correct answer)
Methanol

Correct answer: Ethanol

CH3-CH2-OH contains two carbon atoms with a hydroxyl group, making it ethanol by IUPAC nomenclature.

Question 140: Which plant hormone is responsible for apical dominance?

Auxin (Correct answer)
Gibberellin
Ethylene
Cytokinin

Correct answer: Auxin

Auxin produced at the apical bud suppresses the growth of lateral buds, a phenomenon called apical dominance.

Question 141: Which of the following is the correct order of boiling points of noble gases?

He < Ne < Ar < Kr < Xe (Correct answer)
He < Ar < Ne < Kr < Xe
Xe < Kr < Ar < Ne < He
Ne < He < Ar < Kr < Xe

Correct answer: He < Ne < Ar < Kr < Xe

Boiling points of noble gases increase with atomic mass due to increasing London dispersion forces: He < Ne < Ar < Kr < Xe.

Question 142: What is the major product of Markovnikov addition of HBr to propene (CH3-CH=CH2)?

Propanol
2-Bromopropane (Correct answer)
1,2-Dibromopropane
1-Bromopropane

Correct answer: 2-Bromopropane

Markovnikov's rule states that H adds to the carbon with more H atoms, so Br adds to the middle carbon of propene, giving 2-bromopropane.

Question 143: The chloramine-T is.

antipyretic
disinfectant (Correct answer)
analgesic
antiseptic

Correct answer: disinfectant

Chloramine-T is an organic compound that releases chlorine, making it a potent oxidizing agent. It is widely used as a disinfectant and antiseptic due to its effectiveness against bacteria, viruses, and fungi. Its applications range from medical and dental settings to water purification.

Question 144: What is the term for the full range of environmental conditions within which an organism can survive and reproduce?

Ecological niche (Correct answer)
Habitat
Biome
Territory

Correct answer: Ecological niche

An ecological niche encompasses the functional role of an organism in its ecosystem, including its habitat, diet, behavior, and interactions with other species.

Question 145: Among the most widely used drugs in medicine iodex is

ethyl salicylate
o-hydroxy benzoic acid
methyl salicylate (Correct answer)
acetyl salicylic acid

Correct answer: methyl salicylate

Iodex is a well-known topical analgesic balm used for relieving muscular and joint pain. Its primary active ingredient is methyl salicylate, commonly known as oil of wintergreen. Methyl salicylate acts as a counter-irritant and anti-inflammatory agent, providing a warming sensation and pain relief when applied to the skin.

Question 146: The corners of a cubic unit cell in a solid "AB" with a NaCl structure are occupied by "A" atoms. The solid's resulting stoichiometry is as follows if all the atoms with faces to one of the axes are eliminated:

A2B
A3B4 (Correct answer)
AB2
A4B3

Correct answer: A3B4

In a solid with a NaCl structure, one type of atom (A) forms an FCC lattice (corners and face centers), and the other (B) occupies octahedral voids (edge centers and body center), resulting in A4B4 initially. If atoms on faces perpendicular to one axis are eliminated, this typically refers to the two face-centered atoms on those opposite faces. These are A atoms, and each contributes 1/2 to the unit cell, so 1 A atom is effectively removed. B atoms, being at edge centers and the body center, are not affected. Thus, the stoichiometry becomes A3B4.

Question 147: On a lab bench, two tiny lead balls with weights of 5 kg and 10 kg are attached at a distance of 100 cm apart. The distance is now only 20 cm after a pupil transfers the larger mass in the direction of the smaller mass. What influenced the gravitational force between the lead balls when the mass was moved?

5
0.4
1
0.2
25 (Correct answer)

Correct answer: 25

The gravitational force (F) between two masses is inversely proportional to the square of the distance (r) between their centers, as described by Newton's Law of Universal Gravitation (F ∝ 1/r²). The initial distance was 100 cm, and the new distance is 20 cm, which is 1/5th of the original distance. Since force is proportional to 1/r², reducing the distance to 1/5th increases the force by a factor of (1 / (1/5)²) = 1 / (1/25) = 25.

Question 148: Which of the following polymers is used in making bulletproof vests?

Nylon-6,6
Kevlar (Correct answer)
Teflon
Bakelite

Correct answer: Kevlar

Kevlar is an aromatic polyamide with exceptional tensile strength, used in bulletproof vests.

Question 149: Ozone (O3) is an allotrope of which element?

Sulfur
Oxygen (Correct answer)
Nitrogen
Carbon

Correct answer: Oxygen

Ozone (O3) is an allotropic form of oxygen, differing from the common diatomic O2 molecule.

Question 150: How can a positively charged rod make a conducting sphere on an insulating surface negatively charged?

Charge by convection
Charge by induction (Correct answer)
Charge by conduction
None of these

Correct answer: Charge by induction

Charging by induction involves bringing a charged object near a conductor without direct contact. When a positively charged rod is brought near a conducting sphere, it attracts electrons to the near side and repels positive charges (or creates a deficit of electrons) on the far side. If the sphere is then grounded while the rod is still nearby, electrons will flow from the ground onto the sphere, leaving it with a net negative charge once the ground connection and rod are removed.

Question 151: Which vitamin is synthesized by the human body upon exposure to sunlight?

Vitamin A
Vitamin D (Correct answer)
Vitamin B12
Vitamin C

Correct answer: Vitamin D

UV-B radiation converts 7-dehydrocholesterol in skin to Vitamin D3 (cholecalciferol) upon sun exposure.

Question 152: Which biogeochemical cycle involves the conversion of atmospheric N2 into usable forms by bacteria?

Carbon cycle
Water cycle
Nitrogen cycle (Correct answer)
Oxygen cycle

Correct answer: Nitrogen cycle

The nitrogen cycle includes nitrogen fixation by bacteria (e.g., Rhizobium) that convert atmospheric N2 into ammonia usable by plants.

Question 153: Chloramphenicol is a

narrow spectrum antibiotic
broad spectrum analgesic
broad spectrum antibiotic (Correct answer)
broad spectrum antibacterial

Correct answer: broad spectrum antibiotic

Chloramphenicol is a powerful antibiotic that inhibits bacterial protein synthesis. It is effective against a wide range of both Gram-positive and Gram-negative bacteria, as well as other microorganisms like rickettsiae and chlamydiae. This broad spectrum of activity against various bacterial types classifies it as a broad-spectrum antibiotic.

Question 154: Which of these is not a result of a mineral nutrition deficiency?

Etiolation
Necrosis (Correct answer)
Shortening internode
Chlorosis

Correct answer: Necrosis

Necrosis, which is the localized death of plant tissue, is a common and well-documented symptom of various severe mineral deficiencies, such as those of potassium, calcium, and magnesium. However, necrosis is also a very general symptom that can be caused by a wide range of other factors, including pathogens, environmental stress, or chemical toxicity. In contrast, symptoms like chlorosis, etiolation, and shortening internodes are often more directly and specifically linked to particular mineral imbalances or nutrient deficiencies, making necrosis less exclusively diagnostic of mineral deficiency compared to the other options.

Question 155: What distinguishes gravitational and electrical forces most significantly?

Electrical forces attract and gravitational forces repel
Gravitational forces obey the inverse square law and electrical forces do not
Electrical forces obey the inverse square law and gravitational forces do not
Gravitational forces are always attractive but electrical forces can be attractive or repulsive (Correct answer)

Correct answer: Gravitational forces are always attractive but electrical forces can be attractive or repulsive

The most significant distinction lies in the nature of the forces. Gravitational forces are always attractive, drawing masses towards each other. In contrast, electrical forces can be either attractive (between opposite charges) or repulsive (between like charges), due to the existence of both positive and negative charges.

Question 156: Vernalization refers to:

Flowering promoted by cold temperature treatment (Correct answer)
Flowering induced by day length
Vegetative growth inhibition by light
Seed germination triggered by red light

Correct answer: Flowering promoted by cold temperature treatment

Vernalization is the process by which prolonged cold temperature exposure promotes or accelerates flowering in certain plants.

Question 157: When light travels from a denser medium to a rarer medium at an angle greater than the critical angle, what phenomenon occurs?

Polarization
Diffraction
Total internal reflection (Correct answer)
Refraction

Correct answer: Total internal reflection

Total internal reflection occurs when light strikes the interface at an angle exceeding the critical angle while traveling from denser to rarer medium.

Question 158: Which of the following is the method through which H2SO4 is used to manufacture detergents?

Cyclohexanol
p-Nitrophenol
cholesterol
Lauryl alcohol (Correct answer)

Correct answer: Lauryl alcohol

Many synthetic detergents, particularly alkyl sulfate detergents, are manufactured through the sulfonation of long-chain alcohols. Lauryl alcohol (dodecanol) is a common starting material that reacts with concentrated sulfuric acid (H2SO4) to form lauryl hydrogen sulfate. This intermediate is then neutralized to produce sodium lauryl sulfate, a widely used anionic surfactant in various cleaning products.

Question 159: The first transitional component is

copper
vanadium
scandium (Correct answer)
nickel

Correct answer: scandium

Transition metals are characterized by having incompletely filled d-orbitals in their common oxidation states. Scandium (Sc), with an atomic number of 21, is the first element in the periodic table to begin filling its 3d subshell, having an electron configuration of [Ar] 3d¹ 4s². Consequently, scandium is recognized as the first transitional component.

Question 160: The correct order of acidic strength among HF, HCl, HBr, HI is:

HF > HI > HBr > HCl
HF > HCl > HBr > HI
HCl > HBr > HI > HF
HI > HBr > HCl > HF (Correct answer)

Correct answer: HI > HBr > HCl > HF

Acid strength increases down the group as bond dissociation enthalpy decreases; HI is the strongest acid and HF the weakest.

Question 161: The 'Fight or Flight' response is triggered by which hormone?

Estrogen
Thyroxine
Insulin
Adrenaline (Epinephrine) (Correct answer)

Correct answer: Adrenaline (Epinephrine)

Adrenaline (epinephrine), secreted by the adrenal medulla, prepares the body for the 'fight or flight' stress response.

Question 162: Of the following, which won't work as an antacid?

aluminium carbonate (Correct answer)
magnesium hydroxide
sodium carbonate
sodium hydrogen carbonate

Correct answer: aluminium carbonate

Antacids are mild bases designed to neutralize excess hydrochloric acid in the stomach. Sodium carbonate, sodium hydrogen carbonate (baking soda), and magnesium hydroxide (milk of magnesia) are all effective bases commonly used as antacids. Aluminium carbonate, however, is generally insoluble and not effectively utilized as an antacid, making it unsuitable for this purpose.

Question 163: The speed of light in vacuum is approximately:

3 × 10^12 m/s
3 × 10^6 m/s
3 × 10^10 m/s
3 × 10^8 m/s (Correct answer)

Correct answer: 3 × 10^8 m/s

The speed of light in vacuum is approximately 3 × 10^8 m/s (299,792,458 m/s exactly).

Question 164: What is the product when a carboxylic acid reacts with an alcohol in the presence of acid catalyst?

Ether
Ketone
Aldehyde
Ester (Correct answer)

Correct answer: Ester

Esterification is the reaction between a carboxylic acid and an alcohol (with H2SO4 catalyst) to produce an ester and water.

Question 165: Which of these plants might not be suitable for hydroponic cultivation?

Cucumber
Strawberries
Carrot (Correct answer)
Tomatoes

Correct answer: Carrot

Hydroponics is generally well-suited for crops with shallow root systems or those that produce fruits and leafy greens. Carrots, however, are deep-rooting taproots that require a substantial, solid medium to develop their characteristic shape and size properly. While technically possible, growing carrots hydroponically is less practical and efficient compared to other crops like strawberries, tomatoes, or cucumbers.

Question 166: A table tennis ball with a conducting tip on it hangs between two metal plates and is supported by a thin thread. One plate is connected to the earth, while the other is to a high-voltage generator, with the ball in between.

Hangs without moving
Swings backward & forward hitting each plate in turn (Correct answer)
Is attracted to the high voltage plate and stays there
Is repelled by an earthed plate and stays there

Correct answer: Swings backward & forward hitting each plate in turn

When the conducting ball touches the high-voltage plate, it acquires the same charge and is then repelled by that plate while being attracted to the earthed plate. Upon contact with the earthed plate, the ball discharges or acquires an opposite charge, causing it to be repelled by the earthed plate and attracted back to the high-voltage plate. This continuous cycle of attraction and repulsion results in the ball swinging back and forth between the two plates.

Question 167: DNA replication occurs during which phase of the cell cycle?

S phase (Correct answer)
M phase
G2 phase
G1 phase

Correct answer: S phase

DNA synthesis and replication occurs during the S (Synthesis) phase of interphase.

Question 168: What size resistor should be placed across the 12V battery's terminals in order to generate 500mA of current?

6Ω
24Ω (Correct answer)
24kΩ
0.042Ω
42Ω

Correct answer: 24Ω

This problem can be solved using Ohm's Law, which states that Voltage (V) = Current (I) × Resistance (R). Given V = 12V and I = 500mA (which is 0.5 Amperes), we can rearrange the formula to find R = V / I. Therefore, R = 12V / 0.5A = 24Ω.

Question 169: Transitional metals typically have color because

none of the above
their penultimate d-subshells are fully filled
they absorb electromagnetic radiations
of d-d transition (Correct answer)

Correct answer: of d-d transition

Transition metal compounds often exhibit vibrant colors due to the presence of partially filled d-orbitals. When white light interacts with these compounds, electrons in lower energy d-orbitals can absorb specific wavelengths and transition to higher energy d-orbitals, a process called d-d transition. The observed color is the complementary color of the light that was absorbed.

Question 170: The dimensional formula for coefficient of viscosity (η) is:

[ML⁻¹T⁻²]
[M⁰L⁰T⁰]
[ML⁻¹T⁻¹] (Correct answer)
[MLT⁻¹]

Correct answer: [ML⁻¹T⁻¹]

From Newton's law of viscosity F = ηA(dv/dx), solving for η gives dimensions [ML⁻¹T⁻¹].

Question 171: Which colour of visible light has the highest frequency?

Red
Green
Violet (Correct answer)
Yellow

Correct answer: Violet

Violet light has the shortest wavelength (~400 nm) in the visible spectrum and therefore the highest frequency.

Question 172: Which of the following tissues participates in the conduction of water?

Xylem fibres and bast fibres
Xylem and Phloem (Correct answer)
Tracheids and trachea
Sclerenchyma and Parenchyma

Correct answer: Xylem and Phloem

Xylem is the primary vascular tissue responsible for the efficient conduction of water and dissolved minerals from the roots throughout the plant. While phloem's main role is transporting sugars, it also contains water as the solvent for these sugars, thus participating in water movement within the plant. Therefore, both xylem and phloem are involved in the overall conduction of water.

Question 173: The process of converting glucose to pyruvate in the absence of oxygen is called:

Beta oxidation
Glycolysis (Correct answer)
Oxidative phosphorylation
Krebs cycle

Correct answer: Glycolysis

Glycolysis is the anaerobic breakdown of glucose into two pyruvate molecules, producing 2 ATP net gain.

Question 174: A transformer has 500 primary turns and 50 secondary turns. If the primary voltage is 220 V, the secondary voltage is:

2200 V
220 V
110 V
22 V (Correct answer)

Correct answer: 22 V

Using V₂/V₁ = N₂/N₁: V₂ = 220 × (50/500) = 22 V.

Question 175: A current-carrying conductor is placed in a magnetic field. The force on the conductor is zero when the angle between the current direction and magnetic field is:

0° (Correct answer)
90°
45°
180°

Correct answer: 0°

The force on a conductor F = BIL sinθ is zero when θ = 0° or 180° (current parallel to field), but θ = 0° is the standard answer.

Question 176: Which of the following statements regarding hydroponics is false?

Technical knowledge required
Requires high investment (Correct answer)
Can be misused to cultivate banned crops
Plants through hydroponics cannot be cultivated everywhere

Correct answer: Requires high investment

Hydroponics, while offering numerous benefits, typically requires a substantial initial investment for setting up specialized equipment, nutrient solutions, and controlled environmental systems. This high upfront cost can be a significant barrier for many potential cultivators. The other options generally represent true challenges or potential downsides associated with hydroponic cultivation.

Question 177: In humans, how many pairs of spinal nerves are present?

24 pairs
42 pairs
12 pairs
31 pairs (Correct answer)

Correct answer: 31 pairs

The human spinal cord gives rise to 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.

Question 178: Which of the following oxoacids of phosphorus is diprotic (dibasic)?

H₃PO₂
H₄P₂O₇
H₃PO₄
H₃PO₃ (Correct answer)

Correct answer: H₃PO₃

H₃PO₃ (phosphorous acid) is diprotic because one H is directly bonded to P (P–H bond), leaving only two ionizable –OH groups.

Question 179: The primary reason for stomach acidity is

release of extra bile juice which increases alkaline medium in the stomach
release of extra gastric acids which decrease the pH level (Correct answer)
indigestion and pain in the large intestine
release of extra bile juice which increases alkaline medium in the stomach

Correct answer: release of extra gastric acids which decrease the pH level

The stomach naturally produces gastric juice, which contains hydrochloric acid (HCl) to aid digestion and kill pathogens. Stomach acidity, often experienced as heartburn, primarily results from the excessive release of these gastric acids. This overproduction significantly lowers the pH level within the stomach, leading to discomfort and indigestion.

Question 180: Meiosis results in daughter cells with:

Double the chromosomes of parent
Identical DNA to parent
Half the chromosomes of parent (Correct answer)
Same number of chromosomes as parent

Correct answer: Half the chromosomes of parent

Meiosis undergoes two division cycles producing four haploid (n) cells from one diploid (2n) parent cell.

NEET (National Eligibility cum Entrance Test)

The NEET exam is a national-level entrance examination in India for students who wish to pursue undergraduate medical (MBBS), dental (BDS), and AYUSH (BAMS, BUMS, BHMS, etc.) courses in government and private institutions.

200

Questions

200 min

Time Limit

50%

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