datavorous/entrance-exam-dataset huggingface dataset:
Energy storage at consumer level is called

Options:
A Gross primary productivity
B Secondary productivity
C Net primary productivity
D Net productivity

The correct answer is:
Secondary productivity

Solution:
The rate at which the consumers convert the chemical energy of their food into their own biomass is called secondary productivity.

Topic: Biology, Ecosystem, NEET
Epidermal cells are often modified to perform specialised functions in plants. Name some of them and function they perform.

Options:

None

Solution:
The epidermal tissue system comprises of one cell thick layer of epidermal tissue and forms the outer most covering of the whole plant body.
Modification of Epidermal Cells Following are the modifications of the epidermal tissue
(i) root hair
Structure
These unicellular hairs are the extensions of epidermal cell of roots in the root hair zone.
Function
They increase the surface area for absorption of water and minerals.
(ii) Epidermal Appendages
Structure
These are called trichomes and are epidermal cell modifications. There any be unicellular or multicellular.
Appendages of epidermis of leaves
A-Stellate hair of a Alyssum
B-Glandular hair of Pelargonium
C-Short glandular hair of Lavandula
D-Floccose hair of Malva
E-Glandular hair of solanum
F-Urtivating hair of Verbascum
Function
They produce some glandular secretions.

Topic: Biology, Anatomy of Flowering Plants
Equation of a circle passing through origin is $\mathrm{x}^{2}+\mathrm{y}^{2}-6 \mathrm{x}$ $+2 \mathrm{y}=0$. What is the equation of one of its diameters?

Options:
A $x+3 y=0$
B $x+y=0$
C $x=y$
D $3 x+y=0$

The correct answer is:
$x+3 y=0$

Solution:
Equation of the given circle is:
$x^{2}+y^{2}-6 x+2 y=0$
$\Rightarrow x(x-6)+y(y+2)=0$
or, $(x-0)(x-6)+(y-0)(y+2)=0$
This is the equation of circle in diameter form. Here, end points of diameter are $(0,0)$ and $(6,-2)$. Hence, equation of diameter is a line which passes through the points $(0,0)$ and $(6,-2)$ which is
$(y-0)=\frac{-2}{6}(x-0) \Rightarrow x+3 y=0$

Topic: Mathematics, Circle, NDA, NDA 2008 (Phase 1)
Equation of line passing through the point \( (1,2) \) and perpendicular to the line
\( y=3 x-1 \)

Options:
A \( x+3 y-7=0 \)
B \( x+3 y+7=0 \)
C \( x+3 y=0 \)
D \( x-3 y=0 \)

The correct answer is:
\( x+3 y-7=0 \)

Solution:
Given line, $y=3 x-1 \rightarrow(1)$
General equation of line is given by
$y=m x+c$
Here $m=3$ and $c=-1$.
Condition for two perpendicular lines is
$m_{1} \cdot m_{2}=-1$
So, $3 m_{2}=-1 \Rightarrow m_{2}=-\frac{1}{3}$
Standard equation of line passing through point $\left(x_{1}, y_{1}\right)$ is given by $\left(y-y_{1}\right)=m\left(x-x_{1}\right)$
Here $\left(x_{1}, y_{1}\right)=(1,2)$ So,
$(y-2)=-\frac{1}{3}(x-1)$
$\Rightarrow-3 y+6=x-1$
$\Rightarrow x+3 y-7=0$

Topic: Mathematics, Vector Algebra, KCET, KCET 2017
Equation of the hyperbola with eccentricity $3 / 2$ and foci at $(\pm 2,0)$ is $5 x^{2}-4 y^{2}=k^{2}$. What is the value of $k$ ?

Options:
A $4 / 3$
B $3 / 4$
C $(4 / 3) \sqrt{5}$
D $(3 / 4) \sqrt{5}$

The correct answer is:
$(4 / 3) \sqrt{5}$

Solution:
Given equation of hyperbola $\Rightarrow \frac{x^{2}}{\frac{k^{2}}{5}}-\frac{y^{2}}{\frac{k^{2}}{4}}=1$
$a=\frac{k}{\sqrt{5}}$ and $b=\frac{k}{2}$
The eccentricity $\frac{3}{2}$ and foci at $(\pm 2,0)$ of $5 x^{2}-4 y^{2}=k^{2}$
Then, $e=\frac{3}{2}$ and $\pm a e=2$
$\Rightarrow \frac{k}{\sqrt{5}} \cdot \frac{3}{2}=2 \Rightarrow k=\frac{4}{3} \sqrt{5}$

Topic: Mathematics, Hyperbola, NDA, NDA 2008 (Phase 2)
Equation of two simple harmonic waves is given by $\mathrm{Y}_1=2 \sin 8 \pi\left(\frac{\mathrm{t}}{0.2}-\frac{\mathrm{x}}{2}\right) \mathrm{m}$ and $\mathrm{Y}_2=4 \sin 8 \pi\left(\frac{\mathrm{t}}{0.16}-\frac{\mathrm{x}}{1.6}\right) \mathrm{m}$ then both waves have

Options:
A same period
B same frequency
C same wavelength
D same velocity

The correct answer is:
same velocity

Solution:
The two equations can be written as
$$
\begin{aligned}
& Y_1=2 \sin 2 \pi\left(\frac{4 t}{0.2}-\frac{4 x}{2}\right)=2 \sin 2 \pi\left(\frac{\mathrm{t}}{0.05}-\frac{\mathrm{x}}{0.5}\right) \\
& \text { and } Y_2=4 \sin 2 \pi\left(\frac{4 \mathrm{t}}{0.16}-\frac{4 \mathrm{x}}{1.6}\right)=2 \sin 2 \pi\left(\frac{\mathrm{t}}{0.04}-\frac{\mathrm{x}}{0.4}\right)
\end{aligned}
$$
Comparing with standard equation
$$
\mathrm{Y}=\mathrm{A} \sin 2 \pi\left(\frac{\mathrm{t}}{\mathrm{T}}-\frac{\mathrm{x}}{\lambda}\right)
$$
We get, for the first wave,
$$
\mathrm{T}=0.05 \mathrm{~s} \text { and } \lambda=0.5 \mathrm{~m}
$$
For the second wave,
$$
\mathrm{T}=0.04 \mathrm{~s} \text { and } \lambda=0.4 \mathrm{~m}
$$
Hence their periods (hence frequencies) are not same.
Their wavelength is also not same.
For first wave, velocity $=\frac{\lambda}{\mathrm{T}}=\frac{0.5}{0.05}=10 \mathrm{~m} / \mathrm{s}$
For second wave, velocity $\frac{0.4}{0.04}=10 \mathrm{~m} / \mathrm{s}$
Hence velocity in same

Topic: Physics, Waves and Sound, MHT CET, MHT CET 2021 (21 Sep Shift 2)
Estrogen and testosterone are steroid hormones, which most likely bind to

Options:
A membrane ion channels
B cytoplasmic receptors
C enzyme-linked membrane receptors
D G-protein linked membrane receptors

The correct answer is:
membrane ion channels

Solution:
Hormonal action depends on whether the hormone is Lipid or water soluble. Lipid soluble hormones can cross the target cell membrane easily, get attached to the mobile receptors within the cytoplasm and reach the nucleus to perform their functions. However water soluble hormones are proteinaceous and these include insulin, oxytocin etc. These cannot cross the cell membrane easily. These get attached to the static receptors on the cell membrane. This attachment triggers the formation of secondary messengers that help these hormones to act on cells. Estrogen and Progesterone are steroid hormones that means these are lipid soluble hormones. Hence these attach to receptors within the cytoplasm.

Topic: Biology, Chemical Coordination and Integration, NEET
Ethylene oxide when treated with Grignard reagent yields:

Options:
A primary alcohol
B secondary alcohol
C tertiary alcohol
D cyclopropyl alcohol

The correct answer is:
primary alcohol

Solution:
Ethylene oxide on treatment with Grignard reagent gives an additive product which on hydrolysis gives primary alcohol.

Topic: Chemistry, Alcohols Phenols and Ethers, NEET, NEET 2006
Ethylene oxide when treated with Grignard reagent yields

Options:
A primary alcohol
B secondary alcohol
C tertiary alcohol
D cyclopropyl alcohol

The correct answer is:
primary alcohol

Solution:

Topic: Chemistry, Alcohols Phenols and Ethers, NEET
Ethylenediamine (en)

Options:
A monodendate ligand and can occupy one position in coordination polyhedron
B bidendate ligand and can occupy two positions in coordination polyhedron
C polydendate ligand
D tridendate ligand and occupy three positions in coordination polyhedron

The correct answer is:
bidendate ligand and can occupy two positions in coordination polyhedron

Solution:
Ethylenediamine is an organic compound with formula $\mathrm{C}_2 \mathrm{H}_4\left(\mathrm{NH}_2\right)_2$.
$$
\mathrm{H}_2 \text { 薑- } \mathrm{CH}_2-\mathrm{CH}_2-\mathrm{N}_2
$$
It act as a bidentate ligand due to the presence of lone pair of electrons on nitrogen atoms and can occupy two positions.

Topic: Chemistry, Coordination Compounds, TS EAMCET, TS EAMCET 2018 (07 May Shift 1)
Evaluate \( \left|\begin{array}{cc}\cos 15 & \sin 15 \\ \sin 75 & \cos 75\end{array}\right| \)

Options:
A \( 1 \)
B \( 00 \)
C \( 12 \)
D \( 13 \)

The correct answer is:
\( 00 \)

Solution:
Given that,
\[
\begin{array}{l}
\left|\begin{array}{l}
\cos 15^{\circ} \sin 15^{\circ} \\
\sin 75^{\circ} \cos 75^{\circ}
\end{array}\right| \\
=\cos 15^{\circ} \cos 75^{\circ}-\sin 15^{\circ} \sin 75^{\circ} \\
=\cos \left(15^{\circ}+75^{\circ}\right)=\cos \left(90^{\circ}\right)=0
\end{array}
\]

Topic: Mathematics, Three Dimensional Geometry, KCET, KCET 2015
Every quadratic equation $a x^{2}+b x+c=0$ where $a, b, c, \in R$ $a \neq 0$ has

Options:
A exactly one real root.
B at least one real root.
C at least two real roots
D at most two real roots

The correct answer is:
at most two real roots

Solution:
Every quadratic equation
$a x^{2}+b x+c=0$, where $a, b, c \in R, a \neq 0$
has at most two real roots.

Topic: Mathematics, Quadratic Equation, NDA, NDA 2014 (Phase 2)
Examples of areas where secondary succession occurs are

Options:
A Abandoned farmlands, newly cooled lava, barerock
B Burned or cut forests, lands that have been flooded
C Bare rock, newly created pond or reservoir
D Newly created pond, lands that have beenflooded

The correct answer is:
Burned or cut forests, lands that have been flooded

Solution:
Secondary succession begins in areas where natural biotic communities have been destroyed such as in abandoned farmlands, burned or cut forests, lands that have been flooded. Since some soil or sediment is present, secondary succession is faster than primary succession.

Topic: Biology, Ecosystem, NEET
Examples of arithmetic growth are,

Options:
A root elongation
B increase in girth
C both a and b
D none of these

The correct answer is:
root elongation

Solution:
The growth that occurs at a constant rate is known as the arithmetic growth, which is followed by the mitotic cell division. Only one daughter cell continues to divide while the other differentiates and other undergoes maturation. Root elongates at a constant rate thus shows arithmetic growth. An increase in girth of plant shows variable growth and it depends upon the environmental condition and is a secondary growth involving differentiation.

Topic: Biology, Plant - Growth and Development, NEET
Examples of some random variables are given below
$1.$ Number of sons among the children of parents with five children
$2.$ Number of sundays in some randomly selected months with 30 days
$3.$ Number of apples in some $3 \mathrm{~kg}$ packets, purchased from a retail shop Which of the above is expected to follow binomial distribution?

Options:
A Variable 1
B Variable 2
C Variable 3
D None of these

The correct answer is:
Variable 2

Solution:
Number of Sundays in some randomly selected months with 30 days follow binomial distribution.

Topic: Mathematics, Probability, NDA, NDA 2007 (Phase 2)
Exoskeleton of arthropods is composed of:

Options:
A Cellulose
B Chitin
C Glucosamine
D Cutin

The correct answer is:
Chitin

Solution:
The largest phylum Arthropoda has certain salient features:

The body has distinct parts, like head, thorax, abdomen.

There is excosketeton made up of chitin.

There are jointed appendages.

Blood vascular system is open type.

Topic: Biology, Animal Kingdom, NEET, NEET 2022 (Phase 1)
Explain briefly
(i) Protonema
(ii) Antheridium
(iii) Archegonium
(iv) Diplontic
(v) Sporophyll
(vi) Isogamy

Options:

None

Solution:
(i) Protonema : The predominant stage of moss gametophyte which directly develops from spore is known as protonema.
(ii) Antheridium : The male sex organ in bryophytes, pteridophytes and gymnosperms is called antheridium. It bears male gamete.
(iii) Archegonium : It is the female sex organ found in bryophytes, pteridophytes and gymnosperms. It bears female gamete.
(iv) Diplontic: In the life cycle of plants when their diploid stage is dominant for long time then this is called diplontic.
(v) Sporophyll : The sporophyte bears sporangia that are subtended by leaf like appendages called sporophylls.
(vi) Isogamy : When the gametes involved in sexual reproduction are morphologically similar then this is called isogamy. These gametes are physiologically different.

Topic: Biology, Plant Kingdom
Explain briefly the 'rivet popper hypothesis' of Paul Ehrlich.

Options:

None

Solution:
The rivet popper hypothesis was given by ecologist Paul Ehrlich to help in the understanding of the contribution species richness. He compared each species with rivet in the body of an airplane.
(i) This hypothesis considers ecosystem to be an airplane and the species to be the rivets joining all parts together.
(ii) If every passenger travelling in the airplane starts taking rivets home (causing a species to become extinct), initially it may not affect flight safety (proper functioning of ecosystem), but over a period of time the plane becomes weak and dangerous (species become endangered and then gradually extinct).

Topic: Biology, Biodiversity and its Conservation
Explain in 2-3 lines each of the following terms with the help of examples taken from different plant tissues.
(a) Differentiation
(b) De-differentiation
(c) Re-differentiation

Options:

None

Solution:
(a) Differentiation is permanent in composition structure size and function of cells, tissue or organs. For example the meristematic tissues in plants gives rise to new cells which then mature and get differentiated into tissue or an organ of the plant, e.g., cells, distal to root apical meristem form root cap, cell of the periphery form epiblema, followed by cortex, etc.
(b) De-differentiation is the process of regain of differentiated cells so that they again become differentiated and able to divide. e.g., in dicot stem, the cortical cells get de-differentiate and become meristematic to form cambium (interfascicular cambium, and fascicular cambiums).
(c) Re-differentiation The cambium cells thus formed, again re-differentiate to form secondary cortex cells, secondary xylem and phloem elements and phelloderm in case of secondary growth of woody dicot plants.

Topic: Biology, Plant - Growth and Development
Explain the following : CO2is a better reducing agent below 710K whereas CO is a better reducing agent above 710K.

Options:
A CO2is more stable than CO below 710K.
B CO has a lower bond dissociation energy than CO2below 710K.
C CO2is reduced to CO below 710K as per Ellingham diagram.
D CO2has a higher standard reduction potential than CO below 710K.

The correct answer is:
CO2is reduced to CO below 710K as per Ellingham diagram.

Solution:
Correct Option is : (C)
CO2is reduced to CO below 710K as per Ellingham diagram.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, NEET
Explain the following terms:
(i) Electrophoresis
(ii) Coagulation
(iii) Dialysis
(iv) Tyndall effect.

Options:

None

Solution:
(i) The colloidal particles are electrically charged, either positive or negative. When an electric current is passed through a colloidal solution, the colloidal particles move towards a positive or a negative terminal. This movement of colloidal particles under applied electric field is known as electrophoresis.
(ii) Coagulation or precipitation: The stability of the lyophobic sols is due to the presence of charge on colloidal particles. If, somehow, the charge is removed, the particles will come nearer to each other to form aggregates (or coagulate) and settle down under the force of gravity. The process of setting down of colloidal particles is called coagulation.
(iii) The process of separating a soluble crystalloid from a colloid is called dialysis. The purification of a colloid by dialysis is based on the fact that colloidal size particles cannot pass through parchment paper or cello phone membrane, whereas small molecules or ions can pass thought it. Thus, when a bag of parchment paper containing a colloidal solution is suspended into pure water, the small molecules and ions pass through the membrane into the pure water and the pure colloidal solution is left behind.
(iv) When a beam of light is passed through a colloidal solution, its path becomes visible. This phenomenon is known as Tyndall effect. It is due to the scattering of light by colloidal particles.

Topic: Chemistry, Surface Chemistry
Explain the following with an example
(i) Kolbe's reaction
(ii) Reimer - Tiemann reaction
(iii) Williamson ether synthesis
(iv) Unsymmetrical ether

Options:

None

Solution:
(i) Kolbe's reaction: Sodium phenoxide when heated with $\mathrm{CO}_2$ at $400 \mathrm{~K}$ under a pressure of 4-7 atmospheres followed by acidification gives 2-hydroxybenzoic acid (salicylic acid) as the major product along with a small amount of 4-hydroxybenzoic acid. This reaction is called Kolbe's reaction.
(ii) Reimer-Tiemann reaction: Treatment of phenol with $\mathrm{CHCl}_3$ in presence of aqueous sodium or potassium hydroxide at $340 \mathrm{~K}$ followed by hydrolysis of the resulting product gives 2-hydroxybenzaldehyde (salicylaldehyde) as the major product. This reaction is called Reimer-Tiemann reaction.
(iii) Williamson's ether synthesis: It involves the treatment of an alkyl halide with a suitable sodium alkoxide to obtain ethers. The sodium alkoxide needed for the purpose is prepared by the action of sodium on a suitable alcohol. In this reaction alkyl halide should primary. Secondary and tertiary halides will predominantly give an alkene.
(iv) Unsymmetrical ether: If the alkyl or aryl groups attached to the oxygen atom are different, ethers are called unsymmetrical ethers. For example, ethylmethylether, methylphenylether, etc.

Topic: Chemistry, Alcohols Phenols and Ethers
Explain the process of secondary growth in the stems of woody angiosperms with the help of schematic diagrams. What is its significance?

Options:

None

Solution:
Secondary growth in dicot stem: It is "permanent increase in thickness due to the activity of vascular cambium and cork cambium in stelar and extrastelar regions". In dicot stem intra fascicular cambium is present. The cells of medullary ray become meristematic and form interfascicular cambium. These two cambiums unite and make a complete cambial ring. The cells of it divide and produce new cells both on its outer and inner sides. The cells formed on the outer side differentiate into secondary phloem while the cells of inner side form secondary xylem. The epidermis is replaced by a secondary protective tissue by increase in growth of the stem of the plant. It is made of phellogen (cork cambium). It arises from the peripheral cells of cortex. The phellogen forms new cells on the outer side which make phellem (cork) and phelloderm on its inner side also. Significance : Secondary growth increases girth or thickness of plant.
Annual rings of woody angiosperms are very distinct and thus helps in determining the age of plant.

Topic: Biology, Anatomy of Flowering Plants
Explain the terms primary and secondary structure of proteins. What is the difference between $\alpha$-helix and $\beta$ pleated sheet structure of proteins?

Options:

None

Solution:
Proteins are made up of one or more polypeptide chains. The specific sequence in which various amino acids are linked with each other to form polypeptide is called its primary structure. Secondary structure refers to the shape which the polypeptide chains assume as a result of
hydrogen bonding between
< smiles>CC(C)=O < /smiles>
and $-\mathrm{NH}-$ groups of the peptide bond. Difference between $\alpha$-helix and $\beta$ pleated sheet structure is as given below:

Topic: Chemistry, Biomolecules
Explain this statement clearly :
"To call a dimensional quantity 'large' or 'small' is meaningless without specifying a standard for comparison." In view of this, reframe the following statements wherever necessary:
(a) atoms are very small objects
(b) a jet plane moves with great speed
(c) the mass of Jupiter is very large
(d) the air inside this room contains a large number of molecules
(e) a proton is much more massive than an electron
(f) the speed of sound is much smaller than the speed of light.

Options:

None

Solution:
Physical quantities are called large or small depending on the unit (standard) of measurement. For example, parsec is equal to $3.08 \times 10^{16} \mathrm{~m}$ or $3.08 \times 10^{12} \mathrm{~km}$ is certainly larger than metre or kilometre.
(a) The size of an atom is much smaller than even the sharp tip of a pin.
(b) A Jet plane moves with a speed greater than that of a superfast train.
(c) The mass of Jupiter is very large compared to that of the earth.
(d) The air inside this room contains more number of molecules than in one mole of air.
(e) This is a correct statement.
(f) This is a correct statement.

Topic: Physics, Units and Dimensions
Explain what is observed
(i) when a beam of light is passed through a colloidal sol.
(ii) an electrolyte, \(\mathrm{NaCl}\) is added to hydrated ferric oxide sol.
(iii) electric current is passed through a colloidal sol.

Options:

None

Solution:
(i) Scattering of light by the colloidal particles takes place and the path of light becomes visible (Tyndall effect).
(ii) The positively charged colloidal particles of \(\mathrm{Fe}(\mathrm{OH})_3\) get coagulated by the oppositely charged \(\mathrm{Cl}^{-}\)ions provided by \(\mathrm{NaCl}\).
(iii) On passing electric current, colloidal particles move towards the oppositely charged electrode where they lose their charge and get coagulated.

Topic: Chemistry, Surface Chemistry
Explain why is sodium less reactive than potassium ?

Options:

None

Solution:
The ionization enthalpy \(\left(\Delta_{\mathrm{i}} \mathrm{H}\right)\) of potassium \(\left(496 \mathrm{~kJ} \mathrm{~mol}^{-1}\right)\) is less than that of sodium \(\left(496 \mathrm{~kJ} \mathrm{~mol}^{-1}\right)\) or more precisely the standard electrode potential \(\left(\mathrm{E}^{\circ}\right)\) of potassium \((-2.925 \mathrm{~V})\) is more negative than that of sodium \((-2.714 \mathrm{~V})\) and hence potassium is more reactive than sodium.

Topic: Chemistry, s Block Elements
Explain why (or how):
(a) in a sound wave, a displacement node is a pressure antinode and vice versa,
(b) bats can ascertain distances, directions, nature, and sizes of the obstacles without any "eyes",
(c) a violin note and sitar note may have the same frequency, yet we can distinguish between the two notes,
(d) solids can support both longitudinal and transverse waves, but only longitudinal waves can propagate in gases, and
(e) the shape of a pulse gets distorted during propagation in a dispersive medium.

Options:

None

Solution:
[QUESTION]
(a) As displacement node is a point of zero displacement the pressure variation is maximum at this point.
Hence it is a pressure antinode.
(b) Bats have the ability to produce and detect ultrasonic waves $(v>20 \mathrm{kHz})$ so they can detect the distance of the object by the interval between their producing the waves and receiving the echo. From the intensity of the echo they detect the nature and size of the object and from the small interval between their receiving the echo by their two ears, they can ascertain the direction of the object.
(c) The quality of the sound produced depends on the overtones produced by the instruments. The Sitar and Violin though may have the same fundamental frequency but they produce different overtone which is an integral multiple of fundamental frequency and hence we can differentiate between the sound of the two.
(d) Gases do not have shear elasticity so only the longitudinal waves can travel through them whereas solids have both volume and shear elasticity and hence both longitudinal and tranverse waves can travel through them.
(e) It is the property of a dispersive medium that waves of different wavelength travel with different speeds in different directions or with different velocities. Thus when a sound pulse which is a combination of waves of different wavelengths travels through it gets distorted.

Topic: Physics, Waves and Sound