Start streak

NEET Full Mock Test: Practice Test 3

Question paper with answer key. Selection Pro

Q1. A body of mass $2\text{ kg}$ is moving in a circular path of radius $1\text{ m}$ with a constant speed of $4\text{ m/s}$. The centripetal force acting on the body is:
  1. $8\text{ N}$
  2. $16\text{ N}$
  3. $32\text{ N}$
  4. $4\text{ N}$

Answer: (C) $32\text{ N}$

Centripetal force $F_c = \frac{m v^2}{r} = \frac{2 \times 4^2}{1} = 32\text{ N}$.

Q2. The work done in lifting a mass $m$ from the surface of the Earth to a height equal to the radius of the Earth $R$ is:
  1. $mgR$
  2. $\frac{1}{2} mgR$
  3. $2mgR$
  4. $\frac{1}{4} mgR$

Answer: (B) $\frac{1}{2} mgR$

$W = \Delta U = -\frac{GMm}{2R} - \left(-\frac{GMm}{R}\right) = \frac{GMm}{2R} = \frac{1}{2} mgR$.

Q3. An ideal transformer has $500$ primary turns and $100$ secondary turns. If the input primary voltage is $220\text{ V}$, the secondary output voltage is:
  1. $1100\text{ V}$
  2. $44\text{ V}$
  3. $22\text{ V}$
  4. $440\text{ V}$

Answer: (B) $44\text{ V}$

Transformer ratio $\frac{V_s}{V_p} = \frac{N_s}{N_p} \implies V_s = 220 \times \frac{100}{500} = 44\text{ V}$.

Q4. The speed of light in a medium of relative permittivity $\epsilon_r = 2$ and relative permeability $\mu_r = 2$ is:
  1. $3 \times 10^8\text{ m/s}$
  2. $1.5 \times 10^8\text{ m/s}$
  3. $6 \times 10^8\text{ m/s}$
  4. $2.25 \times 10^8\text{ m/s}$

Answer: (B) $1.5 \times 10^8\text{ m/s}$

Refractive index $n = \sqrt{\mu_r \epsilon_r} = \sqrt{2 \times 2} = 2$. Speed in medium $v = \frac{c}{n} = \frac{3 \times 10^8}{2} = 1.5 \times 10^8\text{ m/s}$.

Q5. The terminal velocity of a small spherical ball falling through a viscous liquid is directly proportional to:
  1. Radius of ball $r$
  2. Square of radius $r^2$
  3. Cube of radius $r^3$
  4. Viscosity coefficient $\eta$

Answer: (B) Square of radius $r^2$

Stokes' law gives terminal velocity $v_t = \frac{2 r^2 (\rho - \sigma) g}{9 \eta}$, hence $v_t \propto r^2$.

Q6. A charged particle $q$ enters a perpendicular magnetic field $B$ with velocity $v$. The kinetic energy of the particle:
  1. Increases continuously
  2. Decreases continuously
  3. Remains constant
  4. Oscillates periodically

Answer: (C) Remains constant

Magnetic force is always perpendicular to velocity ($ vec{F} = q vec{v} \times vec{B}$), doing zero work. Thus kinetic energy remains constant.

Q7. In a full-wave rectifier, if the input AC signal frequency is $50\text{ Hz}$, the fundamental ripple frequency of output is:
  1. $25\text{ Hz}$
  2. $50\text{ Hz}$
  3. $100\text{ Hz}$
  4. $200\text{ Hz}$

Answer: (C) $100\text{ Hz}$

For a full-wave rectifier, output ripple frequency is twice the input frequency ($2 \times 50\text{ Hz} = 100\text{ Hz}$).

Q8. The energy of hydrogen atom in ground state is $-13.6\text{ eV}$. The energy of $n=3$ state is:
  1. $-4.53\text{ eV}$
  2. $-1.51\text{ eV}$
  3. $-3.4\text{ eV}$
  4. $-0.85\text{ eV}$

Answer: (B) $-1.51\text{ eV}$

$E_n = \frac{-13.6}{n^2}\text{ eV}$. For $n=3$, $E_3 = \frac{-13.6}{9} = -1.51\text{ eV}$.

Q9. Which of the following molecules has maximum covalent character according to Fajan's rules?
  1. $\text{LiF}$
  2. $\text{LiCl}$
  3. $\text{LiBr}$
  4. $\text{LiI}$

Answer: (D) $\text{LiI}$

Larger anion size increases polarizability. Since $\text{I}^-$ is largest, $\text{LiI}$ has maximum covalent character.

Q10. The IUPAC name of $\text{CH}_3-\text{CO}-\text{CH}_2-\text{CHO}$ is:
  1. 3-oxobutanal
  2. 3-oxobutanol
  3. 2-oxobutanal
  4. 1,3-dioxobutane

Answer: (A) 3-oxobutanal

Aldehyde group ($-\text{CHO}$) has higher priority than ketone ($-\text{CO}-$). Numbering starts from $-\text{CHO}$ carbon: 3-oxobutanal.

Q11. What is the standard enthalpy of formation of an element in its standard reference state?
  1. Negative
  2. Positive
  3. Zero
  4. Variable depending on temperature

Answer: (C) Zero

By convention, standard enthalpy of formation ($\Delta_f H^\circ$) for an element in its most stable standard state is taken as zero.

Q12. Which alkali metal ion has highest ionic mobility in aqueous solution?
  1. $\text{Li}^+$
  2. $\text{Na}^+$
  3. $\text{K}^+$
  4. $\text{Cs}^+$

Answer: (D) $\text{Cs}^+$

$\text{Cs}^+$ has largest ionic radius and smallest hydrated radius, giving it least hydration drag and highest ionic mobility.

Q13. Aniline reacts with nitrous acid ($\text{NaNO}_2 + \text{HCl}$) at $0-5^\circ\text{C}$ to yield:
  1. Phenol
  2. Benzene
  3. Benzene diazonium chloride
  4. Nitrobenzene

Answer: (C) Benzene diazonium chloride

Primary aromatic amines undergo diazotization with $\text{HNO}_2$ at $273-278\text{ K}$ to form benzene diazonium salts.

Q14. The Coordination Number of central metal ion in $[\text{Fe}(\text{EDTA})]^-$ is:
  1. $2$
  2. $4$
  3. $6$
  4. $8$

Answer: (C) $6$

$\text{EDTA}^{4-}$ is a hexadentate ligand binding through 2 nitrogen and 4 oxygen donor atoms, so CN = 6.

Q15. Which of the following colligative properties is most suitable to determine molecular mass of polymers?
  1. Relative lowering of vapour pressure
  2. Elevation of boiling point
  3. Depression of freezing point
  4. Osmotic pressure

Answer: (D) Osmotic pressure

Osmotic pressure produces measurable values even at very low molar concentrations of macromolecules.

Q16. Electrolysis of aqueous $\text{NaCl}$ solution using inert electrodes produces which gas at cathode?
  1. $\text{Cl}_2$
  2. $\text{O}_2$
  3. $\text{H}_2$
  4. $\text{Na}$ vapor

Answer: (C) $\text{H}_2$

Water has higher reduction potential than $\text{Na}^+$ ion, so $\text{H}^+$ is reduced to hydrogen gas ($\text{H}_2$) at the cathode.

Q17. The primary $\text{CO}_2$ acceptor in C4 plants is:
  1. RuBP
  2. Phosphoenolpyruvate (PEP)
  3. OAA
  4. PGA

Answer: (B) Phosphoenolpyruvate (PEP)

In mesophyll cells of C4 plants, PEP (3-carbon compound) acts as initial $\text{CO}_2$ acceptor catalyzed by PEP carboxylase.

Q18. The term 'Omnis cellula-e cellula' (all cells arise from pre-existing cells) was proposed by:
  1. Schleiden
  2. Schwann
  3. Rudolf Virchow
  4. Robert Hooke

Answer: (C) Rudolf Virchow

Rudolf Virchow (1855) modified cell theory by establishing that new cells originate from pre-existing cells.

Q19. Which floral family shows marginal placentation in its ovary?
  1. Fabaceae
  2. Solanaceae
  3. Liliaceae
  4. Brassicaceae

Answer: (A) Fabaceae

Fabaceae (pea family) possesses monocarpellary ovary with marginal placentation.

Q20. The enzyme restriction endonuclease cleaves DNA at specific sequences called:
  1. Promoter sites
  2. Palindromic sequences
  3. Poly-A tails
  4. Exon regions

Answer: (B) Palindromic sequences

Restriction enzymes inspect DNA length to recognize specific symmetrical palindromic nucleotide sequences.

Q21. Pneumatophores (respiratory roots) are modified roots present typically in:
  1. Hydrophytes
  2. Halophytes (Mangroves)
  3. Xerophytes
  4. Mesophytes

Answer: (B) Halophytes (Mangroves)

Mangrove plants (Rhizophora) growing in swampy saline soils produce erect negative geotropic pneumatophores for oxygen uptake.

Q22. During aerobic respiration, maximum ATP molecules are synthesized via electron transport chain in:
  1. Cytoplasm
  2. Inner mitochondrial membrane
  3. Mitochondrial matrix
  4. Perimitochondrial space

Answer: (B) Inner mitochondrial membrane

ETC complexes and ATP synthase ($F_0-F_1$ particles) are embedded in inner mitochondrial membrane (cristae).

Q23. The cross between an $F_1$ individual and its homozygous recessive parent is termed:
  1. Monohybrid cross
  2. Back cross
  3. Test cross
  4. Reciprocal cross

Answer: (C) Test cross

A test cross identifies unknown genotype by crossing $F_1$ hybrid with homozygous recessive parent.

Q24. Which pyramid is ALWAYS upright in any stable ecosystem without exception?
  1. Pyramid of Biomass
  2. Pyramid of Energy
  3. Pyramid of Numbers
  4. Pyramid of Height

Answer: (B) Pyramid of Energy

Pyramid of energy is always upright because energy is lost as heat at every successive trophic level.

Q25. Which cell organelles in human sperm contain enzymes aiding penetration of egg membrane (corona radiata)?
  1. Centrioles
  2. Acrosome
  3. Mitochondrial spiral
  4. Axoneme

Answer: (B) Acrosome

Acrosome is a modified Golgi structure containing sperm lysins like hyaluronidase.

Q26. Glomerular filtration rate (GFR) in a healthy human adult is approximately:
  1. $125\text{ mL/min}$
  2. $180\text{ mL/min}$
  3. $500\text{ mL/min}$
  4. $12.5\text{ mL/min}$

Answer: (A) $125\text{ mL/min}$

Normal GFR is around $125\text{ mL/min}$, amounting to about $180\text{ L}$ of filtrate per day.

Q27. Insulin deficiency or resistance leads to diabetes mellitus characterized by glucose in urine called:
  1. Uremia
  2. Glycosuria
  3. Ketonuria
  4. Hematuria

Answer: (B) Glycosuria

Excretion of glucose in urine is termed glycosuria, a hallmark sign of Diabetes Mellitus.

Q28. Which cranial nerve in human body is the longest and innervates visceral organs?
  1. Optic nerve (II)
  2. Trigeminal nerve (V)
  3. Vagus nerve (X)
  4. Hypoglossal nerve (XII)

Answer: (C) Vagus nerve (X)

Vagus nerve ($X^{\text{th}}$ cranial nerve) is the longest parasympathetic cranial nerve supplying thoracic and abdominal viscera.

Q29. In humerus bone, the head fits into which cavity of pectoral girdle?
  1. Acetabulum
  2. Glenoid cavity
  3. Foramen magnum
  4. Sigmoid notch

Answer: (B) Glenoid cavity

The head of humerus articulates with glenoid cavity of scapula forming shoulder ball-and-socket joint.

Q30. In human menstrual cycle, sudden surge of which hormone induces ovulation around day 14?
  1. FSH
  2. LH
  3. Progesterone
  4. Estrogen

Answer: (B) LH

LH surge (rapid rise in Luteinizing Hormone) triggers rupture of Graafian follicle and release of ovum.

Q31. The enzyme present in human saliva that hydrolyzes starch into maltose is:
  1. Pepsin
  2. Salivary Amylase (Ptyalin)
  3. Trypsin
  4. Lipase

Answer: (B) Salivary Amylase (Ptyalin)

Salivary amylase breaks down about 30% starch into disaccharide maltose at optimum pH 6.8.

Q32. A person with blood group AB positive is considered a universal recipient because:
  1. RBCs lack both A and B antigens
  2. Plasma lacks anti-A and anti-B antibodies
  3. RBCs carry anti-A antibodies
  4. Plasma contains both anti-A and anti-B antibodies

Answer: (B) Plasma lacks anti-A and anti-B antibodies

Blood group AB plasma lacks anti-A and anti-B antibodies, avoiding agglutination with donated RBCs.