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NEET Full Mock Test: Practice Test 1

Question paper with answer key. Selection Pro

Q1. The dimensions of Planck's constant are identical to that of:
  1. Linear momentum
  2. Angular momentum
  3. Energy
  4. Power

Answer: (B) Angular momentum

Both Planck's constant ($h$) and angular momentum ($L$) have dimensions $[M L^2 T^{-1}]$.

Q2. A particle is projected with velocity $u$ at an angle $\theta$ with the horizontal. The time of flight $T$ is given by:
  1. $\frac{u\sin\theta}{g}$
  2. $\frac{2u\sin\theta}{g}$
  3. $\frac{u\cos\theta}{g}$
  4. $\frac{2u\cos\theta}{g}$

Answer: (B) $\frac{2u\sin\theta}{g}$

Total time of flight $T = \frac{2u_y}{g} = \frac{2u\sin\theta}{g}$.

Q3. A wire of resistance $R$ is stretched to double its original length keeping volume constant. Its new resistance becomes:
  1. $2R$
  2. $4R$
  3. $R/2$
  4. $R/4$

Answer: (B) $4R$

$R = \rho \frac{L}{A}$. When length is doubled ($L'=2L$), area becomes $A'=A/2$, so $R' = 4R$.

Q4. The magnetic field at the center of a circular coil of radius $R$ carrying current $I$ is:
  1. $\frac{\mu_0 I}{2R}$
  2. $\frac{\mu_0 I}{4\pi R}$
  3. $\frac{\mu_0 I}{2\pi R}$
  4. $\frac{\mu_0 I}{4R}$

Answer: (A) $\frac{\mu_0 I}{2R}$

Standard Biot-Savart formula for the magnetic field at the center of a current loop is $B = \frac{\mu_0 I}{2R}$.

Q5. The focal length of a convex lens in air is $20\text{ cm}$. When immersed completely in water ($n_w = 4/3$), its focal length becomes ($n_g = 3/2$):
  1. $20\text{ cm}$
  2. $40\text{ cm}$
  3. $80\text{ cm}$
  4. $10\text{ cm}$

Answer: (C) $80\text{ cm}$

Using Lens Maker's formula, $f_{\text{water}} = 4 \times f_{\text{air}} = 4 \times 20 = 80\text{ cm}$.

Q6. The de Broglie wavelength associated with an electron accelerated through a potential difference of $V$ volts is approximately:
  1. $\frac{12.27}{\sqrt{V}}\text{ \AA}$
  2. $\frac{1.227}{\sqrt{V}}\text{ \AA}$
  3. $\frac{122.7}{\sqrt{V}}\text{ \AA}$
  4. $\frac{0.1227}{\sqrt{V}}\text{ \AA}$

Answer: (A) $\frac{12.27}{\sqrt{V}}\text{ \AA}$

$\lambda = \frac{h}{\sqrt{2meV}} = \frac{12.27}{\sqrt{V}}\text{ \AA}$.

Q7. A body falls freely from rest. The ratio of distances covered in the $1^{\text{st}}$, $2^{\text{nd}}$, and $3^{\text{rd}}$ seconds is:
  1. $1:2:3$
  2. $1:4:9$
  3. $1:3:5$
  4. $1:5:9$

Answer: (C) $1:3:5$

Distance covered in $n^{\text{th}}$ second $S_n \propto (2n-1)$. Ratio for $n=1,2,3$ is $1:3:5$ (Galileo's Law of Odd Numbers).

Q8. The half-life of a radioactive substance is $10\text{ days}$. The time required for $75\%$ of the substance to decay is:
  1. $10\text{ days}$
  2. $20\text{ days}$
  3. $30\text{ days}$
  4. $40\text{ days}$

Answer: (B) $20\text{ days}$

$75\%$ decay leaves $25\%$ ($1/4^{\text{th}}$) remaining, which takes $2$ half-lives $= 2 \times 10 = 20\text{ days}$.

Q9. The hybridization and shape of $\text{SF}_6$ molecule are respectively:
  1. $sp^3d$, Trigonal bipyramidal
  2. $sp^3d^2$, Octahedral
  3. $d^2sp^3$, Square planar
  4. $sp^3$, Tetrahedral

Answer: (B) $sp^3d^2$, Octahedral

$\text{SF}_6$ has 6 bond pairs and 0 lone pairs on S, giving $sp^3d^2$ hybridization and octahedral geometry.

Q10. What is the pH of a $10^{-8}\text{ M } \text{HCl}$ solution at $25^\circ\text{C}$?
  1. $8$
  2. $7$
  3. $6.98$
  4. $7.02$

Answer: (C) $6.98$

In dilute acids, $[\text{H}^+]$ from water ($10^{-7}\text{ M}$) must be considered: total $[\text{H}^+] = 1.1 \times 10^{-7}\text{ M}$, yielding $\text{pH} \approx 6.98$.

Q11. The oxidation state of Chromium in Potassium Dichromate ($\text{K}_2\text{Cr}_2\text{O}_7$) is:
  1. $+3$
  2. $+4$
  3. $+6$
  4. $+7$

Answer: (C) $+6$

$2(+1) + 2(x) + 7(-2) = 0 \implies 2x = 12 \implies x = +6$.

Q12. Which of the following compounds does NOT undergo Aldol condensation?
  1. Acetaldehyde
  2. Benzaldehyde
  3. Propananal
  4. Acetone

Answer: (B) Benzaldehyde

Benzaldehyde lacks $\alpha$-hydrogens and therefore undergoes Cannizzaro reaction instead of Aldol condensation.

Q13. The SI unit of rate constant for a first-order chemical reaction is:
  1. $\text{mol L}^{-1} \text{s}^{-1}$
  2. $\text{L mol}^{-1} \text{s}^{-1}$
  3. $\text{s}^{-1}$
  4. $\text{mol}^{-2} \text{L}^2 \text{s}^{-1}$

Answer: (C) $\text{s}^{-1}$

Unit of $k = (\text{mol L}^{-1})^{1-n} \text{s}^{-1}$. For $n=1$, unit is $\text{s}^{-1}$.

Q14. The primary structure of a protein is stabilized and maintained mainly by:
  1. Hydrogen bonds
  2. Peptide bonds
  3. Disulfide linkages
  4. Ionic bonds

Answer: (B) Peptide bonds

Primary structure refers to the sequence of amino acids joined linearly by covalent peptide bonds ($-\text{CO-NH-}$).

Q15. Which of the following elements has the highest electronegativity according to Pauling scale?
  1. Oxygen
  2. Chlorine
  3. Fluorine
  4. Nitrogen

Answer: (C) Fluorine

Fluorine is the most electronegative element in the periodic table with a value of $4.0$ on the Pauling scale.

Q16. According to IUPAC nomenclature, the correct name for $\text{CH}_3\text{-CH(OH)-CH}_2\text{-COOH}$ is:
  1. 3-hydroxybutanoic acid
  2. 2-hydroxybutanoic acid
  3. beta-hydroxybutyric acid
  4. 4-hydroxybutanoic acid

Answer: (A) 3-hydroxybutanoic acid

Numbering starts from carboxyl carbon: $\text{C}_1(\text{COOH})-\text{C}_2\text{H}_2-\text{C}_3\text{H(OH)}-\text{C}_4\text{H}_3$. Name is 3-hydroxybutanoic acid.

Q17. In photorespiration (C3 plants), the cell organelles involved in sequence are:
  1. Chloroplast, Peroxisome, Mitochondria
  2. Chloroplast, Mitochondria, Peroxisome
  3. Peroxisome, Chloroplast, Mitochondria
  4. Mitochondria, Peroxisome, Chloroplast

Answer: (A) Chloroplast, Peroxisome, Mitochondria

Photorespiration occurs sequentially in Chloroplast $\rightarrow$ Peroxisome $\rightarrow$ Mitochondria.

Q18. Double fertilization is a characteristic features unique to which group of plants?
  1. Gymnosperms
  2. Pteridophytes
  3. Angiosperms
  4. Bryophytes

Answer: (C) Angiosperms

Double fertilization (syngamy + triple fusion) is unique to Angiosperms.

Q19. The phenotypic ratio of a typical Mendelian dihybrid cross in $F_2$ generation is:
  1. $3:1$
  2. $1:2:1$
  3. $9:3:3:1$
  4. $9:7$

Answer: (C) $9:3:3:1$

Mendel's dihybrid cross yields a phenotypic ratio of $9:3:3:1$ in the $F_2$ generation.

Q20. Gaseous plant hormone responsible for ripening of fruits is:
  1. Auxin
  2. Gibberellin
  3. Ethylene
  4. Abscisic Acid

Answer: (C) Ethylene

Ethylene ($\text{C}_2\text{H}_4$) is a gaseous plant hormone that promotes climacteric fruit ripening.

Q21. During which phase of mitosis do chromosomes line up along the equatorial plate?
  1. Prophase
  2. Metaphase
  3. Anaphase
  4. Telophase

Answer: (B) Metaphase

At Metaphase, chromosomes align at the metaphase plate (equator) attached to spindle fibers via kinetochores.

Q22. Which enzyme unwinds the double helical DNA structure during replication?
  1. DNA Polymerase
  2. DNA Ligase
  3. Helicase
  4. Primase

Answer: (C) Helicase

Helicase breaks hydrogen bonds between nitrogenous base pairs to unwind the DNA double helix.

Q23. The functional unit of environment in which living organisms interact with non-living components is:
  1. Biome
  2. Ecosystem
  3. Community
  4. Population

Answer: (B) Ecosystem

An Ecosystem is a functional structural unit where biotic elements interact with abiotic factors.

Q24. C4 plants are ecologically adapted to hot dry climates because they avoid:
  1. Transpiration
  2. Photorespiration
  3. Glycolysis
  4. Kreb's cycle

Answer: (B) Photorespiration

C4 plants concentrate $\text{CO}_2$ around RuBisCO in bundle sheath cells, preventing oxygenation and avoiding photorespiration.

Q25. Which antibody is predominant in human colostrum providing natural passive immunity to newborn?
  1. IgG
  2. IgM
  3. IgA
  4. IgE

Answer: (C) IgA

IgA is secretory antibody present abundantly in colostrum (first milk).

Q26. Which factor causes oxygen-hemoglobin dissociation curve to shift to the RIGHT?
  1. High $pO_2$
  2. High $pCO_2$ and High $[H^+]$
  3. Low temperature
  4. High pH

Answer: (B) High $pCO_2$ and High $[H^+]$

High $pCO_2$, low pH (high $H^+$ concentration), elevated temperature, and high 2,3-BPG cause right shift (Bohr effect), decreasing affinity.

Q27. The functional structural unit of the human kidney is called:
  1. Neuron
  2. Nephron
  3. Glomerulus
  4. Henle's Loop

Answer: (B) Nephron

Each human kidney contains approximately 1 million nephrons, which serve as its basic structural and functional unit.

Q28. 'Saheli', a non-steroidal once-a-week oral contraceptive pill, was developed at:
  1. AIIMS, New Delhi
  2. CDRI, Lucknow
  3. ICMR, New Delhi
  4. IISC, Bangalore

Answer: (B) CDRI, Lucknow

Saheli was formulated by scientists at Central Drug Research Institute (CDRI) in Lucknow, India.

Q29. The joint present between Atlas (C1) and Axis (C2) vertebrae in humans is a:
  1. Hinge joint
  2. Pivot joint
  3. Ball and Socket joint
  4. Gliding joint

Answer: (B) Pivot joint

The atlanto-axial joint between atlas and axis is a pivot synovial joint allowing rotational movement of head.

Q30. In response to low blood pressure/blood volume, Juxtaglomerular (JG) cells secrete:
  1. Aldosterone
  2. Renin
  3. Angiotensinogen
  4. ANF

Answer: (B) Renin

JG cells release the enzyme Renin, which converts angiotensinogen to angiotensin I to initiate the RAAS cascade.

Q31. Which hormone is master regulator of basal metabolic rate (BMR) in human body?
  1. Insulin
  2. Thyroxine ($T_4$)
  3. Adrenaline
  4. Parathormone

Answer: (B) Thyroxine ($T_4$)

Thyroid hormones ($T_3$ and $T_4$) regulate Basal Metabolic Rate (BMR) across tissues.

Q32. According to Darwin, organic evolution is driven by:
  1. Inheritance of acquired characters
  2. Natural selection acting on small, directional variations
  3. Mutational saltations
  4. Genetic drift alone

Answer: (B) Natural selection acting on small, directional variations

Darwin's theory of evolution attributes speciation to Natural Selection acting on minor, continuous variations.