datavorous/entrance-exam-dataset huggingface dataset:
What is the value of rate constant of first order reaction, if it takes 15 minutes for consumption of $20 \%$ of reactants?

Options:
A $1 \cdot 84 \times 10^{-2} \min ^{-1}$
B $1 \cdot 38 \times 10^{-2} \min ^{-1}$
C $1 \cdot 07 \times 10^{-2} \min ^{-1}$
D $1 \cdot 48 \times 10^{-2} \min ^{-1}$

The correct answer is:
$1 \cdot 48 \times 10^{-2} \min ^{-1}$

Solution:
(B)
$[\mathrm{A}]_{0}=$ Original amount of reactant $=100$
$[\mathrm{A}]_{t}=$ Reactant remaining unreacted $=100-20=80$
For first order reaction,
$\begin{aligned}
\mathrm{k} &=\frac{2.303}{\mathrm{t}} \log _{10} \frac{[\mathrm{A}]_{0}}{[\mathrm{~A}]_{t}} \\
\therefore \mathrm{k} &=\frac{2.303}{15 \mathrm{~min}} \log _{10} \frac{100}{80}=0.0148 \mathrm{~min}^{-1} \\
\therefore \mathrm{k} &=1.48 \times 10^{-2} \mathrm{~min}^{-1}
\end{aligned}$

Topic: Chemistry, Chemical Kinetics, MHT CET, MHT CET 2020 (16 Oct Shift 2)
What is the value of the maximum kinetic energy acquired by electron due to radiation of wavelength $100 \mathrm{~nm}$ ?

Options:
A $12 \mathrm{eV}$
B $6.2 \mathrm{eV}$
C $100 \mathrm{eV}$
D $300 \mathrm{eV}$

The correct answer is:
$6.2 \mathrm{eV}$

Solution:
From photoelectric equation, kinetic energy :
$\begin{aligned}& \mathrm{K}=\mathrm{hc}\left(\frac{1}{\lambda}-\frac{1}{\lambda_0}\right) \\& =\frac{6.6 \times 10^{-34} \times 3 \times 10^8}{1.6 \times 10^{-19}} \times\left(\frac{1}{100 \times 10^{-} 9}-\frac{1}{200 \times 10^{-} 9}\right) \mathrm{eV} \\& =6.2 \mathrm{eV}\end{aligned}$

Topic: Physics, Dual Nature of Matter, JEE Main
What is the velocity of the bob of a simple pendulum at its mean position, if it is able to rise to vertical height of $10 \mathrm{~cm}$ (Take $g=9.8 \mathrm{~m} / \mathrm{s}^2$ )

Options:
A $0.6 \mathrm{~m} / \mathrm{s}$
B $1.4 \mathrm{~m} / \mathrm{s}$
C $1.8 \mathrm{~m} / \mathrm{s}$
D $2.2 \mathrm{~m} / \mathrm{s}$

The correct answer is:
$1.4 \mathrm{~m} / \mathrm{s}$

Solution:
$v=\sqrt{2 g h}=\sqrt{2 \times 9.8 \times 0.1}=\sqrt{1.96}=1.4 \mathrm{~m} / \mathrm{s}$

Topic: Physics, Center of Mass Momentum and Collision, JEE Main
What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with n = 4 to an energy level with n = 2?
[Given: Rydberg constant = 1 912  A o ]

Options:
A 185.2 nm
B 285.2 nm
C 385.2 nm
D 486.4ânm

The correct answer is:
486.4 nm

Solution:
1 Î» â=â R H Z 2 1 n 1 2 â 1 n 2 2
=â 1 Î» â=â R H âÃâ 1 2 1 2 2 â 1 4 2
⇒ 1 λ  =  1 912  ×  3 16
âÎ»=4864â A o
â´âÎ»=486.4ânm

Topic: Chemistry, Structure of Atom, JEE Main
What is the work done in stretching a uniform metal
wire of length from 2 m to 2.004 m with an area of cross
section $10^{-6} \mathrm{~m}^2 ?$
[Young's modulus of the wire = 2 × 1011 N/m2]

Options:
A 1.6 J
B 0.8 J
C 8 J
D 16 J

The correct answer is:
0.8 J

Solution:
$\begin{aligned} & \text { Work done }=\frac{1}{2} \mathrm{Kx}^2 \\ & =\frac{1}{2} \frac{\mathrm{yA}}{\ell} \times(\Delta \ell)^2=\frac{1}{2} \times \frac{2 \times 10^{11} \times 10^{-6}}{2} \times(0.004)^2 \\ & =0.8 \mathrm{~J}\end{aligned}$

Topic: Physics, Mechanical Properties of Solids, JEE Main
What is the $\mathrm{x}$ -coordinate of the point on the curve $\mathrm{f}(\mathrm{x})=$ $\sqrt{\mathrm{x}}(7 \mathrm{x}-6)$, where the tangent is parallel to $\mathrm{x}$ -axis?

Options:
A $-\frac{1}{3}$
B $\frac{2}{7}$
C $\frac{6}{7}$
D $\frac{1}{2}$

The correct answer is:
$\frac{2}{7}$

Solution:
$\begin{aligned} \mathrm{f}(\mathrm{x}) &=\sqrt{\mathrm{x}}(7 \mathrm{x}-6)=7 \mathrm{x}^{3 / 2}-6 \mathrm{x}^{1 / 2} \\ \mathrm{f}^{\prime}(\mathrm{x}) &=7 \times \frac{3}{2} \mathrm{x}^{1 / 2}-6 \times \frac{1}{2} \mathrm{x}^{-1 / 2} \end{aligned}$
When tangent is parallel to $\mathrm{x}$ axis $\mathrm{f}^{\prime}(\mathrm{x})=0$ or, $\frac{21}{2} \mathrm{x}^{1 / 2}-3 \mathrm{x}^{-1 / 2}=0$
$\frac{21}{2} \sqrt{x}=\frac{3}{\sqrt{x}}$
or, $7 x=2 \Rightarrow x=\frac{2}{7}$

Topic: Mathematics, Application of Derivatives, JEE Main
What is true about Bt toxin?

Options:
A The concerned Bacillus has antitoxins
B The inactive protoxin gets converted into active form in the insect gut
C Bt protein exists as active toxin in the Bacillus
D The activated toxin enters the ovaries of the pest to sterillise it and thus prevent its multiplication.

The correct answer is:
The inactive protoxin gets converted into active form in the insect gut

Solution:
No Solution Available

Topic: Biology, Biotechnology and Its Applications, NEET, NEET 2009 (Mains)
What is true about RBCs in humans?

Options:
A They carry about 20-25 per cent of $\mathrm{CO}_2$
B They transport 99.5 per cent of $\mathrm{O}_2$
C They transport about 80 per cent oxygen only and the rest 20 per cent of it is transported in dissolved state in blood plasma
D They do not carry $\mathrm{CO}_2$ at all

The correct answer is:
They carry about 20-25 per cent of $\mathrm{CO}_2$

Solution:
Nearly 20-25 per cent of $\mathrm{CO}_2$ is transported by RBCs. It is caused by haemoglobin as carbamino haemoglobin. 70 per cent of $\mathrm{CO}_2$ is carried as bicarbonates.
About 97 per cent of $\mathrm{O}_2$ is transported by RBCs in the blood. The remaining 3 per cent of $\mathrm{O}_2$ is carried in dissolved state through the plasma.

Topic: Biology, Body Fluids and Circulation, NEET, NEET 2010 (Screening)
What is true about the isolated small tribal populations?

Options:
A There is no change in population size as they have a large gene pool
B There is a decline in population as boys marry girls only from their own tribe
C Hereditary diseases like colour blindness do not spread in the isolated population
D Wrestlers who develop strong body muscles in their life time pass this character on to their progeny

The correct answer is:
There is a decline in population as boys marry girls only from their own tribe

Solution:
The acquired character such as strong muscles of a wrestler obtained by regular exercise will not be transmitted to the next generation. Gene pool of a population will consist of a large number of genes which will vary in their frequencies. These frequencies also depend on proportion of various genotypes in the total population. Small tribal population will have small gene pool.
Hereditary diseases like colour blindness will spread in isolated population due to inbreeding.
There is a decline in population as boys marry girls only from their own tribe, this is due to absence of gene migration/gene flow.

Topic: Biology, Organisms and Populations, NEET, NEET 2008 (Mains)
What is true about T-lymphocytes in mammals?

Options:
A there are three main typescytotoxic T-cells, helper T-cells and suppressor T-cells
B these originate in lymphoid tissues
C they scavenge damaged cells and cellular debris
D these are produced in thyroid

The correct answer is:
there are three main typescytotoxic T-cells, helper T-cells and suppressor T-cells

Solution:
T cells account for about \(80 \%\) of all lymphocytes. They are named T cells because they mature in the thymus, a gland found in the chest. There are three types of T cell lymphocytes:
- Cytotoxic T cell
- Suppressor T cell
- Helper T cell
Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate \(B\) cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic \(T\) cells to kill infected target cells. A cytotoxic T cell is a Tlymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways. The regulatory T cells formerly known as suppressor T cells are a subpopulation of T cells that modulate the immune system, maintain tolerance to self-antigens, and prevent autoimmune disease.
So, the correct answer is 'There are three main types-cytotoxic T-cells, helper T-cells, and suppressor T-cells'.

Topic: Biology, Human Health and Diseases, NEET, NEET 2003
What is turgidity in plant growth?

Options:
A The process of cell enlargement
B The release of metabolic energy
C The process of releasing enzymatic activities
D The release of metabolic energy and water uptake

The correct answer is:
The process of cell enlargement

Solution:
Turgidity in plant growth refers to the process of cell enlargement, which is necessary for extension growth and is maintained by water uptake.

Topic: Biology, Plant - Growth and Development, NEET
What is vital capacity of our lungs?

Options:
A Total lungs capacity minus residual volume
B Inspiratory reserve volume plus tidal volume
C Total lungs capacity minus expiratory reserve volume
D Inspiratory reserve volume plus expiratory reserve volume

The correct answer is:
Total lungs capacity minus residual volume

Solution:
Vital capacity $=T V+I R V+E R V$
Total lung capacity $=\mathrm{VC}+\mathrm{RV}$
So we can say that $\mathrm{VC}=$ Total lung capacity - Residual volume.

Topic: Biology, Breathing and Exchange of Gases, NEET, NEET 2008 (Mains)
What is $X$ in the following reaction?
$2 \mathrm{CH}_3 \mathrm{COCH}_3 \stackrel{\mathrm{Ba}(\mathrm{OH})_2}{\longrightarrow} X$

Options:
A

B

C

D

The correct answer is:

Solution:

Topic: Chemistry, Aldehydes and Ketones, JEE Main
What is 'X' in the given reaction?

Options:
A
B
C
D

The correct answer is:

Solution:

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main, JEE Main 2021 (25 Feb Shift 2)
What is Y ?

Options:
A

B

C

D

The correct answer is:

Solution:
The reaction series takes place as

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
What is $Y$ in the following reaction?
$\begin{aligned} & \mathrm{C}_2 \mathrm{H}_3 \mathrm{I}+\mathrm{NaOC}_2 \mathrm{H}_3 \longrightarrow X+\mathrm{Nal} \\ & X+2 \mathrm{HI} \stackrel{\Delta}{\longrightarrow} 2 \mathrm{Y}+\mathrm{H}_2 \mathrm{O} \\ & \end{aligned}$

Options:
A $\mathrm{C}_2 \mathrm{H}_6$
B $\mathrm{C}_2 \mathrm{H}_5 \mathrm{I}$
C $\mathrm{C}_2 \mathrm{H}_4$
D $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OC}_2 \mathrm{H}_5$

The correct answer is:
$\mathrm{C}_2 \mathrm{H}_5 \mathrm{I}$

Solution:
According to the conditions of question

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main
What is Y in the following sequence of reactions?

2-methyl-2-bromo propane â dryâether Mg X â H 2 O Y

Options:
A Propane
B 2-methyl propene
C 2-methyl propane
D 2-methyl butane

The correct answer is:
2-methyl propane

Solution:

Topic: Chemistry, Hydrocarbons, JEE Main
What is $Z$ in the following reaction sequence?

Options:
A $\mathrm{C}_6 \mathrm{H}_5 \mathrm{CO}_2 \mathrm{H}$
B $\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}$
C $\mathrm{C}_6 \mathrm{H}_5 \mathrm{CHO}$
D $\mathrm{C}_6 \mathrm{H}_6$

The correct answer is:
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{CHO}$

Solution:

Topic: Chemistry, Amines, JEE Main
What is Z in the following reaction sequence?

C 6 H 5 NH 2 â i NaNO 2 +HCl/273 K ii H 3 PO 2 + H 2 O iii CO, HCl anhy . AlCl 3 /CuCl Z.

Options:
A C 6 H 5 CO 2 H
B C 6 H 5 OH
C C 6 H 5 CHO
D C 6 H 6

The correct answer is:
C 6 H 5 CHO

Solution:

Topic: Chemistry, Amines, JEE Main
What is $Z$ in the following reactions?

Options:
A $\left(\mathrm{CH}_3\right) \mathrm{BH}_2$
B $\left(\mathrm{CH}_3\right)_4 \mathrm{~B}_2 \mathrm{H}_2$
C $\left(\mathrm{CH}_3\right)_3 \mathrm{~B}_2 \mathrm{H}_3$
D $\left(\mathrm{CH}_3\right)_6 \mathrm{~B}_2$

The correct answer is:
$\left(\mathrm{CH}_3\right)_4 \mathrm{~B}_2 \mathrm{H}_2$

Solution:
$\begin{aligned} & \mathrm{BCl}_3+\mathrm{H}_2 \underset{{ }^4 0^{\circ} \mathrm{C}}{\stackrel{\mathrm{Cu}-\mathrm{Al}}{\longrightarrow}} \underset{\substack{\text { diborane } \\ \text { 'X' }}}{\mathrm{B}_2 \mathrm{H}_6}+\mathrm{HCl} \\ & \underset{ }{\mathrm{B}_2 \mathrm{H}_6}+4 \mathrm{CH}_3 \mathrm{Cl} \stackrel{\text { Methylation }}{\longrightarrow} \underset{{ }^{\prime} \mathrm{Z}}{\longrightarrow}\left(\mathrm{CH}_3\right)_4 \mathrm{~B}_2 \mathrm{H}_2 \\ & \end{aligned}$

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
What is (Z) is in the following sequence of reaction?

HCâ¡CHâi 2NaNH2ii 2CH3IXâHgSO4, H2SO4Yâi NaOH+Br2ii H3O+Z

Options:
A CH3CH2CH2CHO
B CH3CH2COCH3
C CH3CH2COOH
D CH3CH2CH2COOH

The correct answer is:
CH3CH2COOH

Solution:
The reaction sequence is as follows

Topic: Chemistry, Hydrocarbons, JEE Main
What kind of evidence suggested that man is more closely related with chimpanzee than with at her hominoid apes?

Options:
A evidence from DNA from sex chromosomes only
B comparison of chromosomes morphology only
C evidence from fossil remains, and the fossil mitochondrial DNA alone
D evidence from DNA extracted from sex chromosomes, autosomes and mitochondria.

The correct answer is:
evidence from DNA extracted from sex chromosomes, autosomes and mitochondria.

Solution:
Chimpanzee is more closely related to man than other hominoids. Chimpanzees are genetically closest to humans, and in fact, chimpanzees share about $98.6 \%$ of our DNA. Some similarities between human and chimpanzee in the chromosome banding pattern in sex chromosomes, autosomes and mitochondria. There is little difference in banding pattern in chromosomes 3 and 6 in human and chimpanzee. Serum test indicate maximum homology between human and chimpanzee.
Related Theory
Humans and monkeys are both primates. But humans are not descended from monkeys or any other primate living today. We do share a common ape ancestor with chimpanzees. It lived between 8 and 6 million years ago. They determined that chimpanzees are more closely related to humans than gorillas.

Topic: Biology, Evolution, NEET, NEET 2004
What macroscopic properties remain constant for a system in equilibrium state?

Options:
A Pressure and temperature
B Volume and mass
C Density and composition
D Energy and entropy

The correct answer is:
Pressure and temperature

Solution:
Pressure and temperature remain constant for a system in an equilibrium state.

Topic: Chemistry, Thermodynamics (C), NEET
What maintains the ionic gradients across the resting membrane of a neuron?

Options:
A Sodium-potassium pump
B Sodium-potassium exchanger
C Sodium-protein pump
D Potassium-protein exchanger

The correct answer is:
Sodium-potassium pump

Solution:
The ionic gradients across the resting membrane are maintained by the active transport of ions by the sodium-potassium pump which transports 3 Na⁺ outwards for 2 K⁺ into the cell.

Topic: Biology, Neural Control and Coordination, NEET
What makes neurons excitable cells?

Options:
A Their membranes are polarised.
B Their membranes are non-polarised.
C Their membranes are partially polarised.
D Their membranes are impermeable to ions.

The correct answer is:
Their membranes are polarised.

Solution:
Neurons are excitable cells because their membranes are in a polarised state, meaning the electrical potential difference across the membrane is maintained by ionic gradients.

Topic: Biology, Neural Control and Coordination, NEET
What mass in miligram of CaCO3 is required to react completely with 25 ml of 0.75 M HCl according to the reaction CaCO3(s)+2HCl(a)→CaCl2(a)+CO2(g)+H2O(l)?

Options:

The correct answer is:
937.5

Solution:
Given
CaCO 3 (s) + 2HCl (aq) →  CaCl 2 (aq) +  CO 2 (g) +  H 2 O (l)
Moles present in 25 ml of 0.75 M HCl =0.751000×25
=0.01875 moles
Since 2 moles react completely with 1 mole  CaCO 3  = 100 g
0.01875 moles react completely with CaCO 3 = 100 2 ×0.01875
0.9375 g=937.5 mg

Topic: Chemistry, Some Basic Concepts of Chemistry, JEE Main
What mass of 95% pure CaCO3 will be required to neutralise 50 mL of 0.5 M HCl solution according to the following reaction?

CaCO3s+2HClaq→CaCl2aq+CO2g+2H2Ol

[Calculate upto second place of decimal point]

Options:
A 1.32 g
B 3.65 g
C 9.50 g
D 1.25 g

The correct answer is:
1.32 g

Solution:
\(\underset{(s)}{\mathrm{CaCO}_3}+\underset{50 \mathrm{~mL}, 0.5 \mathrm{M}}{2 \mathrm{HCl}(\mathrm{aq})} \longrightarrow \underset{(\mathrm{aq})}{\mathrm{CaCl}_2}+\underset{(g)}{\mathrm{CO}_2}+\underset{(l)}{2 \mathrm{H}_2 \mathrm{O}}\)
the number of moles of HCl taken \(=0.5 \times 0.05\)
\(=0.025\) moles
As we can see that from the above balanced equation is one mole of \(\mathrm{CaCO}_3(s)\) requires 2 moles of \(\mathrm{HCl}(\mathrm{aq})\) therefore, for 0.025 moles of \(\mathrm{HCl}(\mathrm{aq}), 0.0125\) moles of \(\mathrm{CaCO}_3(s)\) will be required.
Mass of 0.0125 moles of \(\mathrm{CaCO}_3(s)=0.0125 \times\) molar mass of \(\mathrm{CaCO}_3\)
\(\begin{aligned}
& =0.0125 \times 100 \\
& =1.25 \mathrm{~g}
\end{aligned}\)
But purity of \(\mathrm{CaCO}_3(s)\) is \(95 \%\). Therefore, the actual amount of \(\mathrm{CaCO}_3(s)\) required is
Percentage purity \(=\frac{\text { weight of pure substance }}{\text { weight of impure sample }} \times 100\)
\(95=\frac{1.25}{\text { weight of impure sample }} \times 100\)
weight of impure sample \(=\frac{1.25 \times 100}{95}\)
\(=1.32 \mathrm{~g}\)
Hence. option 1 is correct.

Topic: Chemistry, Some Basic Concepts of Chemistry, JEE Main
What may be expected to happen when phosphine gas is mixed with chlorine gas

Options:
A The mixture only cools down
B $\mathrm{PCl}_3$ and $\mathrm{HCl}$ are formed and the mixture warms up
C $\mathrm{PCl}_5$ and $\mathrm{HCl}$ are formed and the mixture cools down
D $\mathrm{PH}_3 \cdot \mathrm{Cl}_2$ is formed with warming up

The correct answer is:
$\mathrm{PCl}_3$ and $\mathrm{HCl}$ are formed and the mixture warms up

Solution:
$\mathrm{PH}_3+4 \mathrm{Cl}_2 \rightarrow \mathrm{PCl}_5+3 \mathrm{HCl}$
(exothermic) make the solution warm

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
What may be expected to happen when phosphine gas is mixed with chlorine gas?

Options:
A
$\mathrm{PCI}_3$ and $\mathrm{HCI}$ are formed and the mixture warms up

B
$\mathrm{PCI}_5$ and $\mathrm{HCI}$ are formed and the mixture cools down

C
$\mathrm{PH}_3 . \mathrm{Cl}_2$ is formed with warming up

D
The mixture only cools down

The correct answer is:
$\mathrm{PCI}_5$ and $\mathrm{HCI}$ are formed and the mixture cools down

Solution:
$\mathrm{PH}_3+4 \mathrm{Cl}_2 \rightarrow \mathrm{PCl}_5+3 \mathrm{HCI}$

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main, JEE Main 2003
What minimum separation between two objects a human eye would be able to resolve, if the eye pupil diameter is $2 \mathrm{~mm}$ and the two objects are $20 \mathrm{~m}$ away from the eye?
(Assume, human eye to be equivalent to a convex lens and consider the average wave length of light as $600 \mathrm{~nm}$ )

Options:
A $7.32 \mathrm{~mm}$
B $8.72 \mathrm{~mm}$
C $6.2 \mathrm{~mm}$
D $4.71 \mathrm{~mm}$

The correct answer is:
$7.32 \mathrm{~mm}$

Solution:
Given, diameter of pupil, $d=2 \mathrm{~mm}=2 \times 10^{-3} \mathrm{~m}$ $D=20 \mathrm{~m}, \lambda=600 \mathrm{~nm}=6 \times 10^{-7} \mathrm{~m}$
For any aparture, limit of resolution is given as,
$\frac{y}{D} \geq \frac{1.22 \lambda}{d} \Rightarrow y \geq \frac{1.22 \lambda D}{d}$[For lens]
Putting the values
$y \geq \frac{6 \times 10^{-7} \times 20 \times 1.22}{2 \times 10^{-3}}$
$\Rightarrow \quad y \geq 6 \times 10^{-3} \times 1.22 \Rightarrow y \geq 7.32 \mathrm{~mm}$
Hence, minimum required separation is $7.32 \mathrm{~mm}$.

Topic: Physics, Ray Optics, JEE Main
What observation is made when a solution of an organic dye is well shaken with animal charcoal?

Options:
A It turns colorless
B It becomes darker
C It solidifies
D It remains unchanged

The correct answer is:
It turns colorless

Solution:
The paragraph mentions that when a solution of an organic dye is well shaken with animal charcoal, the filtrate turns colorless.

Topic: Chemistry, Surface Chemistry, NEET
What occurs during plasmolysis in a plant cell?

Options:
A Water moves into the cell
B The cell membrane shrinks away from the cell wall
C The cell enlarges
D The cell remains unchanged

The correct answer is:
The cell membrane shrinks away from the cell wall

Solution:
Plasmolysis occurs when water moves out of the cell and the cell membrane shrinks away from the cell wall.

Topic: Biology, Transport in Plants, NEET
What occurs during the formation of an antibonding molecular orbital?

Options:
A The electron waves cancel each other.
B The electron waves reinforce each other.
C The electron waves remain unchanged.
D The electron waves combine into a single wave.

The correct answer is:
The electron waves cancel each other.

Solution:
During the formation of an antibonding molecular orbital, the electron waves cancel each other due to destructive interference.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
What occurs when an evacuated container is partially filled with a liquid?

Options:
A The liquid solidifies.
B The liquid evaporates to fill the remaining volume with vapor.
C The liquid separates into its constituent elements.
D The liquid becomes denser.

The correct answer is:
The liquid evaporates to fill the remaining volume with vapor.

Solution:
When an evacuated container is partially filled with a liquid, a portion of the liquid evaporates to fill the remaining volume with vapor.

Topic: Chemistry, States of Matter, NEET
What percentage of kinetic energy of a moving particle is transferred to a stationary particle when it strikes the stationary particle of 5 times its mass?
(Assume the collision to be head-on elastic collision)

Options:
A 50.0%
B 66.6%
C 55.6%
D 33.3%

The correct answer is:
55.6%

Solution:
After collision,

Applying momentum conservation,

mu=mv1+5mv2 ⇒u=v1+5v2 ...1

Coefficient of restitution, e=1=v2-v1u

∴ u=v2-v1 ...2

Adding 2u=6v2 ⇒v2=u3 and u=u3-v1

∴ v1=u3-u=-2u3

Percentage change in kinetic energy =12mv12-12mu212mu2×100

=v12-u2u2×100=4u29-u2u2×100 =-59×100 =55.6%

Topic: Physics, Center of Mass Momentum and Collision, JEE Main, JEE Main 2022 (27 Jun Shift 1)
What percentage of O₂ is carried in a dissolved state through plasma?

Options:
A 0%
B 3%
C 7%
D 20-25%

The correct answer is:
3%

Solution:
Approximately 3% of O₂ is carried in a dissolved state through plasma, while the remaining 97% is transported by red blood cells (RBCs).

Topic: Biology, Breathing and Exchange of Gases, NEET
What percentage of oxygen is present in the compound \( \mathrm{CaCO}_{3} \cdot 3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} ? \)

Options:
A \( 40.54 \% \)
B \( 35.56 \% \)
C \( 15.40 \% \)
D \( 41.95 \% \)

The correct answer is:
\( 41.95 \% \)

Solution:
% of O=GAMOxygen×No. of Oxygen atomGMM×100GMMCaCO3 = 100g and GMMCa3PO42 =310% of O=16×27100+3×310×100=41.95%

Topic: Chemistry, Some Basic Concepts of Chemistry, JEE Main
What percentage of the total area in hilly regions does the National Forest Policy suggest to be under forests?

Options:
A 30%
B 67%
C 33%
D 66%

The correct answer is:
67%

Solution:
The National Forest Policy developed by the Indian government gives the main attention in maintaining proper ecological balance and environmental stability in the forest parts of the country and suggested that the protection of forest is the responsibility of the people. It also proposed that along with the forest department, certain village groups will assist in managing of forest areas. As per the NFP (1988), 67% of the forest area covers the hilly regions and 33% forests in the plains.

Topic: Biology, Biodiversity and its Conservation, NEET
What power is required by the engine to maintain a rotor at a uniform angular speed of 200 rad s^-1 when transmitting a torque of 180 N m?

Options:
A 9,000 W
B 18,000 W
C 36,000 W
D 72,000 W

The correct answer is:
36,000 W

Solution:
Correct Option is : (C)
36,000 W

Topic: Chemistry, Rotational Motion, NEET