NEET Full Mock Test: Practice Test 6

1. $\frac{1}{4\pi\varepsilon_0} \frac{2q}{d}$
2. Zero
3. $\frac{1}{4\pi\varepsilon_0} \frac{4q}{d}$
4. $\frac{1}{4\pi\varepsilon_0} \frac{q}{d^2}$

Answer: (B) Zero

Potential at midpoint $V = V_1 + V_2 = \frac{1}{4\pi\varepsilon_0}\frac{q}{d/2} + \frac{1}{4\pi\varepsilon_0}\frac{-q}{d/2} = 0$.

1. $3\ \Omega$
2. $6\ \Omega$
3. $12\ \Omega$
4. $2.4\ \Omega$

Answer: (A) $3\ \Omega$

The diameter divides the wire into two semi-circular halves, each having resistance $6\ \Omega$. Connected in parallel: $R_{eq} = \frac{6 \times 6}{6 + 6} = 3\ \Omega$.

1. $f$
2. $2f$
3. $\frac{f}{2}$
4. $4f$

Answer: (B) $2f$

Closed pipe fundamental frequency $f_{closed} = \frac{v}{4L} = f$. Open pipe fundamental frequency $f_{open} = \frac{v}{2L} = 2f$.

1. $mgR$
2. $\frac{1}{2}mgR$
3. $2mgR$
4. $\frac{1}{4}mgR$

Answer: (A) $mgR$

Binding energy at Earth's surface is $\frac{GMm}{R} = mgR$. To send it to infinity, initial $KE = mgR$.

1. AND gate
2. NAND gate
3. NOR gate
4. OR gate

Answer: (B) NAND gate

NAND gate truth table produces $0$ only when $A=1$ and $B=1$.

1. $+2.5\text{ D}$
2. $-2.5\text{ D}$
3. $+5.0\text{ D}$
4. $-5.0\text{ D}$

Answer: (A) $+2.5\text{ D}$

$P_1 = \frac{100}{20} = +5\text{ D}$, $P_2 = \frac{100}{-40} = -2.5\text{ D}$. Net power $P = P_1 + P_2 = +5 - 2.5 = +2.5\text{ D}$.

1. $T$
2. $\sqrt{T}$
3. $T^2$
4. $\frac{1}{\sqrt{T}}$

Answer: (B) $\sqrt{T}$

$v_{rms} = \sqrt{\frac{3RT}{M}}$, which shows $v_{rms} \propto \sqrt{T}$.

1. Wavelength
2. Speed
3. Frequency
4. Amplitude

Answer: (C) Frequency

Frequency is a characteristic property of the source emitting light and remains constant during refraction.

1. $\text{SO}_2$
2. $\text{H}_2\text{O}$
3. $\text{BeCl}_2$
4. $\text{O}_3$

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

$\text{BeCl}_2$ has $sp$ hybridization with $180^\circ$ bond angle and linear geometry.

1. Benzene
2. Toluene
3. Benzoic acid
4. Anisole

Answer: (A) Benzene

Heating phenol with zinc dust causes reduction to yield benzene and $\text{ZnO}$.

1. Caprolactam only
2. Hexamethylenediamine and Adipic acid
3. Styrene and 1,3-Butadiene
4. Ethylene glycol and Terephthalic acid

Answer: (B) Hexamethylenediamine and Adipic acid

Nylon-6,6 is a condensation polymer of hexamethylenediamine and adipic acid.

1. $\text{Fe}^{2+}$
2. $\text{Mn}^{2+}$
3. $\text{Cr}^{3+}$
4. $\text{Cu}^{2+}$

Answer: (B) $\text{Mn}^{2+}$

$\text{Mn}^{2+}$ has $3d^5$ configuration with 5 unpaired electrons ($n=5$), giving maximum magnetic moment $\mu = \sqrt{5(5+2)} = 5.92\text{ BM}$.

1. $\text{s}^{-1}$
2. $\text{mol L}^{-1}\text{ s}^{-1}$
3. $\text{L mol}^{-1}\text{ s}^{-1}$
4. $\text{L}^2\text{ mol}^{-2}\text{ s}^{-1}$

Answer: (B) $\text{mol L}^{-1}\text{ s}^{-1}$

For zero-order, $\text{Rate} = k[A]^0 \implies k = \text{Rate} = \text{mol L}^{-1}\text{ s}^{-1}$.

1. Ammoniacal Silver Nitrate solution
2. Alkaline Copper Sulfate solution
3. Aqueous Potassium Permanganate
4. Neutral Ferric Chloride solution

Answer: (A) Ammoniacal Silver Nitrate solution

Tollens' reagent is an ammoniacal silver nitrate solution containing $[\text{Ag}(\text{NH}_3)_2]^+$.

1. $\text{CH}_3\text{COOH}$ and $\text{CH}_3\text{COONa}$
2. $\text{NH}_4\text{OH}$ and $\text{NH}_4\text{Cl}$
3. $\text{HCl}$ and $\text{NaCl}$
4. $\text{NaOH}$ and $\text{NaCl}$

Answer: (A) $\text{CH}_3\text{COOH}$ and $\text{CH}_3\text{COONa}$

An acidic buffer consists of a weak acid ($\text{CH}_3\text{COOH}$) and its salt with a strong base ($\text{CH}_3\text{COONa}$).

1. $sp^3$ and $sp^2$
2. $sp^2$ and $sp^2$
3. $sp^3$ and $sp$
4. $sp$ and $sp^2$

Answer: (A) $sp^3$ and $sp^2$

In $\text{CH}_3-\text{CH}=\text{CH}_2$, C3 ($\text{CH}_3$) is $sp^3$ hybridized and C2 ($=\text{CH}-$) is $sp^2$ hybridized.

1. Subsidiary cells
2. Bulliform cells
3. Trichomes
4. Lenticels

Answer: (A) Subsidiary cells

Subsidiary cells are modified epidermal cells closely surrounding guard cells.

1. Promoter gene
2. Operator gene
3. Structural gene z
4. Regulator gene

Answer: (B) Operator gene

In absence of inducer, repressor protein binds to operator region preventing RNA polymerase from transcribing operon.

1. Chloroplast
2. Mitochondrion
3. Golgi body
4. Endoplasmic reticulum

Answer: (B) Mitochondrion

Mitochondria produce cellular energy in the form of ATP via oxidative phosphorylation.

1. DNA Polymerase I
2. DNA Ligase
3. Helicase
4. RNA Primase

Answer: (B) DNA Ligase

DNA ligase joins discontinuous Okazaki fragments synthesized on lagging strand.

1. Active transport
2. Osmosis
3. Imbibition
4. Turgor pressure

Answer: (B) Osmosis

Root hair cells absorb water down a water potential gradient by osmosis.

1. cry gene
2. lac gene
3. pBR322 gene
4. ori gene

Answer: (A) cry gene

The crystal insecticidal protein is encoded by *cry* genes (e.g., *cryIAc*, *cryIIAb*).

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Answer: (B) Metaphase

Chromosomes are highly condensed and aligned on equatorial plane during metaphase, making it ideal for morphological study.

1. Iron
2. Magnesium
3. Calcium
4. Manganese

Answer: (B) Magnesium

Magnesium ($Mg^{2+}$) forms the central atom of the porphyrin ring of chlorophyll.

1. Parathyroid gland
2. Thyroid gland
3. Adrenal cortex
4. Pancreas

Answer: (B) Thyroid gland

Thyrocalcitonin (TCT) is secreted by parafollicular cells of thyroid gland and reduces blood $Ca^{2+}$ levels.

1. Bicuspid (Mitral) valve
2. Tricuspid valve
3. Aortic semilunar valve
4. Eustachian valve

Answer: (B) Tricuspid valve

Tricuspid valve Guards the right atrioventricular opening and prevents backflow of blood into right atrium.

1. Hepatic lobule
2. Glisson's capsule
3. Crypts of Lieberkuhn
4. Kupffer cell

Answer: (A) Hepatic lobule

Hepatic lobules are structural units of liver containing hepatic cells arranged in cords.

1. Infundibulum
2. Ampulla
3. Isthmus
4. Uterus

Answer: (B) Ampulla

Fertilization occurs at the ampullary region of the oviduct/fallopian tube.

1. Ligament
2. Tendon
3. Cartilage
4. Areolar tissue

Answer: (B) Tendon

Tendons are dense regular connective tissue structures that attach muscles to bones.

1. Cushing's syndrome
2. Addison's disease
3. Grave's disease
4. Acromegaly

Answer: (B) Addison's disease

Underproduction of hormones by adrenal cortex leads to Addison's disease.

1. Dissolved in plasma
2. Oxyhemoglobin
3. Carbamino-hemoglobin
4. Bicarbonate ions

Answer: (B) Oxyhemoglobin

About $97\%$ of oxygen is transported by RBCs in the form of oxyhemoglobin.

1. Trypsinogen
2. Pepsinogen
3. Renin
4. Ptyalin

Answer: (A) Trypsinogen

Pancreatic juice contains zymogens including trypsinogen, chymotrypsinogen, and procarboxypeptidase.