datavorous/entrance-exam-dataset huggingface dataset:
During ecological succession:

Options:
A The establishment of a new biotic community is very fast in its primary phase
B The numbers and types of animals remain constant
C The changes lead to a community that is in near equilibrium with the environment and is called pioneer community
D The gradual and predictable change in species composition occurs in a given area

The correct answer is:
The gradual and predictable change in species composition occurs in a given area

Solution:
Ecological succession involves a gradual and fairly predictable change in the species composition of a given area.

Topic: Biology, Ecosystem, NEET
During electrolysis of water the volume of O2 liberated is 2.24  dm 3 . The volume of hydrogen liberated, under same conditions will be

Options:
A 2.24Â dm3
B 1.12Â dm3
C 4.48 dm3
D 0.56Â dm3

The correct answer is:
4.48 dm3

Solution:
H 2 O→ H 2 + 1 2 O 2
During electrolysis, volumes of O2 and H2 liberated are in the ratio of 1 : 2 Hence, volume of H2 liberated =2×2.24 d m 3
=4.48 d m 3

Topic: Chemistry, Electrochemistry, JEE Main
During emergency which of the following hormone is secreted?

Options:
A Aldosterone
B Thyroxine
C Adrenalin
D Calcitonin

The correct answer is:
Adrenalin

Solution:
Adrenalin (epinephrine) is secreted by Chromaffin cells of adrenal medulla. The secretion of adrenalin is directly controlled by the autonomic nervous system, but not under the control of pituitary.
Adrenalin is also called 'emergency hormone' because it contributes the fright, fight or flight reactions' which occur in condition of emergency. Increase in emotional disturbance increases the secretion of adrenalin, accelerating the rate of respiration, dilating respiratory passage, increasing blood pressure, heart beat, sugar level and stimulating cellular metabolism.Aldosterone, is a mineralocorticoid or salt retaining hormone secreted by adrenal cortex. Its basic funtion is in conservation of sodium and water and dimination of potassium.Thyroxine (tri-iodothyronine) is manufactured in thyroid gland and is synthesized from iodine. Its main function is to control metabolism, regulating tissue growth and development.Calcitonin orThyrocalcitonin (TCT) is a non-iodized hormone, secreted by parafollicular cells of thyroid. Its main role is to lower the amount of calcium and phosphate in the blood.

Topic: Biology, Chemical Coordination and Integration, JIPMER, JIPMER 2009
During formation of CHCl3 from C2H5OH and bleaching powder, which one of the following processes does not occur

Options:
A Hydrolysis
B Oxidation
C Reduction
D Chlorination

The correct answer is:
Reduction

Solution:
In Haloform reaction chlorination followed by oxidation. Hydrolysis of bleaching powder produces chlorine and calcium hydroxide.
CaOCl2+H2O→HydrolysisCa(OH)2+Cl2
CH3CH2OH+Cl2→OxidationCH3CHO+2HCl

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
During ground wave propagation earth behaves like a

Options:
A Leaky capacitor
B Leaky Inductor
C Series combination of capacitor and inductor
D Parallel combination of capacitor and inductor

The correct answer is:
Leaky capacitor

Solution:
Any horizontal component of electric field which is in contact with earth is short circuited by earth. So earth behaves like a leaky capacity. It forms a resistor in shunt with a capacitor.

Topic: Physics, Communication System, JEE Main
During halogen test, sodium fusion extract is boiled with concentrated HNO3 to

Options:
A remove unreacted sodium
B decompose cyanide or sulphide of sodium
C extract halogen from organic compound
D maintain the pH of extract.

The correct answer is:
decompose cyanide or sulphide of sodium

Solution:
The sodium fusion extract is first boiled with concentrated nitric acid to decompose cyanide or sulphide of sodium formed during Lassaigne's test. These ions would otherwise interfere with silver nitrate test for halogens.

Topic: Chemistry, Amines, JEE Main, JEE Main 2022 (25 Jun Shift 2)
During hybridization offsprings with hybrid vigour superior to both parents are self-pollinated for a few successive generations to

Options:
A Retain their parental characters
B Remove their parental characters
C Get homozygosity
D Segregate characters

The correct answer is:
Get homozygosity

Solution:
The advantage of self-pollination lies in the genetic structure maintained within the crop. Self-pollination results in splitting the crop's gene-pool into independent homozygous lines. Due to this, the preservation of varietal identity becomes easy. One major advantage of self- over cross-pollination is the fact that self-pollination isolates the crop reproductively from its wild progenitor.

Topic: Biology, Strategies for Enhancement in Food Production, NEET
During inelastic collision between two bodies, which of the following quantities always remain conserved?

Options:
A Total kinetic energy

B Total mechanical energy

C Total linear momentum

D Speed of each body

The correct answer is:
Total linear momentum

Solution:
According to the question, consider the two bodies as system, the total external force on the system will be zero.
Hence, in an inelastic collision KE does not conserved but total linear momentum of the system remain conserved.

Topic: Physics, Work Power Energy
During inelastic collision between two objects, which of the following quantity always remains
conserved?

Options:
A Total linear momentum
B Total kinetic energy
C Speed of each body
D Total mechanical energy

The correct answer is:
Total linear momentum

Solution:
Since no external forces are acting on the colliding bodies during collision, thus total linear momentum is always conserved in all type of collisions but kinetic energy in not conserved in all collisions.
Kinetic energy is conserved in perfectly elastic collision only but some kinetic energy is lost in inelastic collisions. So, total kinetic energy is not conserved in inelastic collision.

Topic: Physics, Center of Mass Momentum and Collision, KCET, KCET 2019
During inspiration,

Options:
A diaphragm contracts and becomes dome shaped
B diaphragm contracts and becomes flat
C diaphragm relaxes and becomes dome shaped
D diaphragm relaxes and becomes flat

The correct answer is:
diaphragm contracts and becomes flat

Solution:
Transport of oxygen from the atmosphere to tissues and transport of carbon dioxide from tissues to the atmosphere is known as the exchange of gases. This occurs due to the partial pressure of gases, and due to this gases flow from high to low pressure. Partial pressure is the pressure of one gas exerted in a mixture of gases. During inspiration external intercostal muscles contract due to which diaphragm also contracts and changes its shape from normal dome shape to flat. This increases the volume due to which pressure inside the lungs decreases and thus air flows from out to in i.e. inspiration takes place.
During inspiration,
External intercostal muscles contract⏐↓Pulls ribs upwards and outwards⏐↓Diaphragm gets flattened⏐↓Results in increase in volume of thoracic cavity⏐↓Lowers pressure in the lungs than atmospheric pressure⏐↓To fill this gap air from outside rushes into lungsExternal intercostal muscles contract↓Pulls ribs upwards and outwards↓Diaphragm gets flattened↓Results in increase in volume of thoracic cavity↓Lowers pressure in the lungs than atmospheric pressure↓To fill this gap air from outside rushes into lungs

Topic: Biology, Breathing and Exchange of Gases, NEET
During ionic flux, uptake of ions into inner space is

Options:
A Active
B Passive
C Energy-dependent
D Both active and energy-dependent

The correct answer is:
Both active and energy-dependent

Solution:
The movement of ions is called flux. The movement of ions into the cell is called influx and outward migration of ions is known as efflux. The energy is considered to be involved in the transport of such free ions across the membrane. The absorption of ions, involving the use of metabolic energy, is called active absorption. Energy used in these mechanisms comes from metabolic activities. Mineral absorption is mainly an active process.

Topic: Biology, Mineral Nutrition, NEET
During muscle contraction in humans, the:

Options:
A sarcomere does not shorten
B A band remains same
C A, H and I bands shorten
D actin filaments shorten.

The correct answer is:
A band remains same

Solution:
During muscle contraction in humans, the A band remains of the same size. Increase in $\mathrm{Ca}^{++}$level into the sarcoplasm leads to the binding of calcium with a subunit of troponin on actin filaments and thereby remove the masking on active sites for myosin. Utilising the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge. This pulls the attached actin filaments towards the centre of ' $A$ ' band. The ' $Z$ ' line attached to these actins are also pulled inwards thereby causing a shortening of the sarcomere, i.e., contraction. It is clear from the above steps, that during shortening of the muscle, i.e., contraction, the 'I' bands get reduced, whereas the ' $A$ ' bands retain the length.
Related Theory
Myofibrils are composed of long myofilaments of actin, myosin, and other associated proteins. These proteins are organized into regions termed sarcomeres, the functional contractile region of the myocyte. Within the sarcomere actin and myosin, myofilaments are interlaced with each other and slide over each other via the sliding filament model of contraction. The regular organization of these sarcomeres gives skeletal and cardiac muscle their distinctive striated appearance.

Topic: Biology, Locomotion and Movement, NEET, NEET 2013 (Karnataka)
During muscular contraction which of the following events occur?
(a) 'H' zone disappears
(b) 'A' band widens
(c) 'I' band reduces in width
(d) Myosin hydrolyzes ATP, releasing the ADP and Pi
(e) Z-lines attached to actins are pulled inwards Choose the correct answer from the options given below.

Options:
A (a), (c), (d), (e) only
B (a), (b), (c), (d) only
C (b), (c), (d), (e) only
D (b), (d), (e), (a) only

The correct answer is:
(a), (c), (d), (e) only

Solution:
The following events take place during muscular contraction.

(1) Myosin hydrolysis ATP into ADP and Pi. The energy released is used to make a cross-bridge with actin filaments. This pulls the actin filaments towards A-band.
(2) 'Z' line attached to these actins are also pulled inwards thereby causing the shortening of the I-band and thus the sarcomere.
(3) The size of the A-band remains constant.
(4) The movement of actins towards the A-band, causes H-zone to disappear.

Topic: Biology, Locomotion and Movement, NEET, NEET 2021
During muscular contraction, which of the following events occur?
(i) H-zone disappears
(ii) A band widens
(iii) I band reduces in width
(iv) Width of A band is unaffected
(v) M line and $Z$ line come closer.

Options:
A (i), (iii), (iv) and (v)
B (i), (ii) and (v)
C (ii), (iv) and (v)
D (i), (ii) and (iii)

The correct answer is:
(i), (iii), (iv) and (v)

Solution:
Muscle contraction is brought about by sliding of the actin filaments over myosin filaments. When a muscle fibril contracts, its A band remains constant and I band shortens. $\mathrm{H}$ zone also disappears as the actin filaments of both sides in each sarcomere may overlap each other at M line.

Topic: Biology, Locomotion and Movement, AIIMS, AIIMS 2012
During nuclear explosion, one of the products is \({ }^{90} \mathrm{Sr}\) with half-life of \(28 \cdot 1\) years. If \(1 \mu \mathrm{g}\) of \({ }^{90} \mathrm{Sr}\) was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically?

Options:

None

Solution:
Radioactive disintegration follow first order kinetics, Decay constant of \({ }^{90} \mathrm{Sr}\),
\(\begin{aligned}
&k=\frac{0 \cdot 693}{t_{1 / 2}}=\frac{0 \cdot 693}{28 \cdot 1 \text { years }} \\
&=2 \cdot 466 \times 10^{-2} \text { years }^{-1}
\end{aligned}\)
Calculation of amount left after 10 years
\(a=1 \mu g, t=10\) years, \(k=2.466 \times 10^{-2}\) years \(^{-1}\), \((a-x)=\) ?
\(\begin{aligned}
\therefore \quad & k=\frac{2 \cdot 303}{t} \log \frac{a}{a-x} \\
& 2 \cdot 466 \times 10^{-2}=\frac{2 \cdot 303}{10} \log \frac{1}{(a-x)} \\
& \log (a-x)=-0 \cdot 1071 \\
(a-x)=\text { Antilog } 1.8929=0.7814 \mu g
\end{aligned}\)
Calculation of amount left after 60 years
\(\begin{aligned}
&a=1 \mu g, t=60 \text { years } \\
&k=2.466 \times 10^{-1} \text { year }^{-1},(a-x)=? \\
&k=\frac{2.303}{t} \log \frac{a}{a-x}
\end{aligned}\)
\(\begin{aligned}
&2.466 \times 10^{-2}=\frac{2.303}{60} \log \frac{1}{(a-x)} \\
&\log (a-x)=-0.6426 \\
&(a-x)=\text { Antilog } 1.3575=0.2278 \mu g .
\end{aligned}\)

Topic: Chemistry, Chemical Kinetics
During nuclear explosion, one of the products is90Sr with half-life of 28.1 years. If 1µg of90Sr was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically.

Options:
A 0.7814 μg of90Sr will remain after 10 years and 0.227 μg of90Sr will remain after 60 years
B 0.7814 μg of90Sr will remain after 10 years and 0.7814 μg of90Sr will remain after 60 years
C 0.227 μg of90Sr will remain after 10 years and 0.227 μg of90Sr will remain after 60 years
D 0.227 μg of90Sr will remain after 10 years and 0.7814 μg of90Sr will remain after 60 years

The correct answer is:
0.7814 μg of90Sr will remain after 10 years and 0.227 μg of90Sr will remain after 60 years

Solution:
Correct Option is : (A)
0.7814 μg of90Sr will remain after 10 years and 0.227 μg of90Sr will remain after 60 years

Topic: Chemistry, Chemical Kinetics, NEET
During phase change, entropy

Options:
A remains constant
B always increases
C always decreases
D may increase or decrease

The correct answer is:
may increase or decrease

Solution:
The entropy of a system during phase change (phase transition) increases, if the phase transition is towards higher internal energy (e.g., during melting) and decreases if the phase transition is towards lower internal energy (e.g., during freezing). Therefore, during phase change, entropy of the system may increase or decrease.

Topic: Physics, Thermodynamics, AP EAMCET, AP EAMCET 2020 (22 Sep Shift 2)
During photosynthesis when PGA is changed into phosphoglyceraldehyde, which of the following reactions occur?

Options:
A oxidation
B reduction
C electrolysis
D hydrolysis

The correct answer is:
reduction

Solution:
Photosynthesis is the process of converting light to chemical energy and using that to produce glucose.
The general word formula for photosynthesis is -
6CO2+12H2O→ C6H12O6+6H2O+6O2 in presence of light and chlorophyll. The whole photosynthesis process is divided into two broad parts -
Light reaction where the light energy is used to generate ATP and NADPH2 which is later used in the Dark reaction to reduce carbon dioxide into glucose (carbohydrate) molecule. The free oxygen released as a byproduct in the photosynthesis occurs by splitting water. The oxygen of the carbon dioxide is used in making the glucose molecule through the Calvin cycle.
The second phase of the photosynthesis process is the light independent reaction where glucose is produced by fixing CO2 . This process occurs in the stroma of the chloroplast and utilizes the products of the light reaction. CO2 fixation is brought about by Calvin cycle or C3 pathway. This cycle involves three mains steps of carboxylation, reduction and regeneration. The important enzyme RuBisCO catalyzes the reaction of CO2 (1C) with 1,5-RUBP (5C) to form an unstable 6C compound which then forms 2 3C compounds - Phosphoglyceric acid (PGA) by hydrolysis. In the next step, PGA is reduced to the phosphoglyceraldehyde using ATP and NADPH. This step is reduction because NADPH donates electrons to reduce PGA.

Topic: Biology, Photosynthesis in Higher Plants, NEET
During phylogenetic studies which of the following is sequenced?

Options:
A rRNA
B mRNA
C mitochondrial RNA
D tRNA

The correct answer is:
rRNA

Solution:
The study of relationships between different groups/species of organisms and their evolutionary development is called phylogeny. It helps in determining the ancestry and evolutionary history of all life forms on Earth.
One of the RNA found in the cell that helps in translation by supporting the protein synthesis organelle ribosomes is the ribosomal RNA (rRNA) which is sent to the cytoplasm from nucleus. rRNA varies between species due to mutation and using its sequence can trace the evolutionary relationships. Also, it is a simpler molecule compared to DNA and its function is same in all organism. Conducting experiments is easier. rRNA study led to the formation of 'Domains' - Bacteria, Archaea and Eukaryotes.

Topic: Biology, The Living World, NEET
During repolarization of nerve:

Options:
A Na+ channels are closed and K+ channels are open inside the nerve membrane.
B K+ gate closes and Na+ gate opens inside the nerve membrane.
C Both K+ and Na+ gates are closed inside the nerve membrane.
D Both gates remain open inside the nerve membrane.

The correct answer is:
Na+ channels are closed and K+ channels are open inside the nerve membrane.

Solution:
The resting state is polarized state. This contains sodium extracellularly while potassium ions are present inside the axons. As impulse arrives Sodium channels open and thus there is influx of sodium. This is state of action potential or depolarization. This continues for only 0.5 msec after which potassium channels open and sodium channels close. This causes efflux of potassium and this is known as repolarization.

Topic: Biology, Neural Control and Coordination, NEET
During sewage treatment, biogases are produced, which include

Options:
A methane, hydrogen sulphide and carbon dioxide
B methane, oxygen and hydrogen sulphide
C hydrogen sulphide, methane and sulphur dioxide
D hydrogen sulphide, nitrogen and methane

The correct answer is:
methane, hydrogen sulphide and carbon dioxide

Solution:
Biogas is a mixture of gases (mainly methane) produced by the microbial activity and which may be used as fuel. During biogas production, the bacteria called methanogens digest the activated sludge and produce a mixture of gases such as methane, hydrogen sulphide, carbon dioxide and hydrogen.

Topic: Biology, Microbes in Human Welfare, NEET, NEET 2013 (All India)
During the borax bead test with CuSO4, a blue green colour of the bead was observed in oxidising flame due to the formation of

Options:
A Cu3B2
B Cu
C CuBO22
D CuO

The correct answer is:
CuBO22

Solution:
Blue green colour is due to formation of CuBO22. Copper gives blue green colour in borax bead test. Reactions which lead to formation of borax bead:

CuSO4⟶ΔCuO+SO3

CuO+B2O3→CuBO22

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main, JEE Main 2023 (29 Jan Shift 1)
During the denaturation of proteins, which of these structures will remain intact ?

Options:
A Primary
B Secondary
C Tertiary
D Quarternary

The correct answer is:
Primary

Solution:
Protein structures are made by condensation of amino acids forming peptide bonds. The sequence of amino acids in a protein is called its primary structure. The secondary structure is determined by the dihedral angles of the peptide bonds, the tertiary structure by the folding of protein chains in space.

Denaturation involves the breaking of many of the weak linkages, or bonds (e.g., hydrogen bonds), within a protein molecule that are responsible for the highly ordered structure of the protein in its natural (native) state.

During denaturation 2° and 3° structures are destroyed but 1° structure remains intact

Topic: Chemistry, Biomolecules, JEE Main, JEE Main 2022 (25 Jul Shift 1)
During the detection of acidic radical present in a salt, a student gets a pale yellow precipitate soluble with difficulty in \(\mathrm{NH}_4 \mathrm{OH}\) solution when sodium carbonate extract was first acidified with dil. \(\mathrm{HNO}_3\) and then \(\mathrm{AgNO}_3\) solution was added. This indicates presence of :

Options:
A \(\mathrm{Br}^{-}\)
B \(\mathrm{I}^{-}\)
C \(\mathrm{Cl}^{-}\)
D \(\mathrm{CO}_3{ }^{2-}\)

The correct answer is:
\(\mathrm{Br}^{-}\)

Solution:
$\begin{array}{ll}
\mathrm{Ag}^{+}+\mathrm{I}^{-} \rightarrow \mathrm{AgI} & \text{Yellow ppt.} \\
\mathrm{Ag}^{+}+\mathrm{Cl}^{-} \rightarrow \mathrm{AgCl} & \text{White ppt} \\
\mathrm{Ag}^{+}+\mathrm{Br}^{-} \rightarrow \mathrm{AgBr} & \text{Pale yellow ppt}
\end{array}$

Topic: Chemistry, Practical Chemistry, JEE Main, JEE Main 2024 (06 Apr Shift 2)
During the electrolysis of an electrolyte, the number of ions produced, is directly proportional to the

Options:
A Time consumed
B Electro chemical equivalent of electrolysis
C Quantity of electricity passed
D Mass of electrons

The correct answer is:
Quantity of electricity passed

Solution:
According to Faraday’s law.

Topic: Chemistry, Electrochemistry, JEE Main
During the emission of a positron from a nucleus, the mass number of the daughter element remains the same but the atomic number

Options:
A is decreased by 1 unit
B is decreased by 2 units
C is increased by 1 unit
D remains unchanged

The correct answer is:
is decreased by 1 unit

Solution:
When a positron is emitted, a proton is converted into neutron and neutrino. Thus, the number of protons and hence the atomic number decreases by one unit.

Topic: Chemistry, Chemical Kinetics, WBJEE, WBJEE 2014
During the formation of a chemical bond

Options:
A energy decreases
B energy increases
C energy of the system does not change
D electron-electron repulsion becomes more than the nucleus-electron attraction

The correct answer is:
energy decreases

Solution:
During the formation of a chemical bond energy of system decreases with the release of energy. This result in stability of bond formex.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
During the formation of the slag by the reaction of flux and impurities which of the following is an example of acidic and basic flux?
(i) FeO+SiO2→FeSiO3
(ii) SiO2+MgO→MgSiO3

Options:
A (i) SiO2 -Acidic flux (ii) MgO-Basic flux
B (i) SiO2 -Basic flux (ii) MgO-Acidic flux
C (i) SiO2 -Basic flux (ii) MgO-Basic flux
D (i) SiO2 -Acidic flux (ii) MgO-Acidic flux

The correct answer is:
(i) SiO2 -Acidic flux (ii) MgO-Basic flux

Solution:
(i) FeObasicimpurity+SiO2acidicflux→FeSiO3slag
(ii) SiO2acidicimpurity+MgObasicflux→MgSiO3slag

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main
During the free expansion of an ideal gas in an isolated chamber,

Options:
A internal energy remains constant

B internal energy decreases

C work done on the system is negative

D temperature increases

The correct answer is:
internal energy remains constant

Solution:
In a free expansion, external pressure pex=0
∴ W=-pex·ΔV=0
and the system is isolated. Heat does not enter or leave, q=0ΔU=q+W=0, where U= internal
energy.

Topic: Chemistry, Thermodynamics (C), KVPY, KVPY 2019 (SA)