datavorous/entrance-exam-dataset huggingface dataset:
Photochemical smog consists of excessive amount of X, in addition to aldehydes, ketones, peroxy acetyl nitrile (PAN). X is:

Options:
A CH4
B CO2
C O3
D CO

The correct answer is:
O3

Solution:
Photochemical smog is formed on the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere.
NO2gâhvNOg+Og
Oxygen atom (nascent) is very reactive and combines with O2 in air to produce ozone.
Og+O2gâO3g

Topic: Chemistry, Environmental Chemistry, NEET
Photochemical smog is characterized by the absence of

Options:
A ozone
B nitrogen dioxide
C carbon dioxide
D PAN

The correct answer is:
carbon dioxide

Solution:
Smoke is formed by a combination of smoke and fog. Photochemical smog resulted from a combination of smoke, hydrocarbons, nitrogen oxide, oxygen along with UV light resulting in the formation of peroxyacetyl nitrate (PAN), ozone and nitrogen oxides consequently leading to reddish-brown smog. Los Angeles was the first place to have experienced the effects of photochemical smog hence also called as Los Angeles smog. Ozone causes damage to mucus membranes whereas PAN damages rubber and inhibits chlorophyll formation in plants

Topic: Biology, Environmental Issues, NEET
Photochemical smog pollution does not contain:

Options:
A PAN (peroxy acyl nitrate)
B ozone
C nitrogen dioxide
D carbon dioxide

The correct answer is:
carbon dioxide

Solution:
The major undesirable components of photochemical smog are nitrogen dioxide $\left(\mathrm{NO}_2\right)$, ozone $\left(\mathrm{O}_3\right)$, PAN (peroxyacetylnitrate), and chemical compounds that contain the $-\mathrm{CHO}$ group (aldehydes).

Topic: Biology, Environmental Issues, NEET, NEET 2006
Photoelectric effect supports quantum nature of light because

1. There is minimum frequency of light below which no photoelectrons are emitted.

2. Electric charge of photoelectrons is quantized.

3. Maximum kinetic energy of photoelectrons depends only on the frequency of light and not on its intensity.

4. Even when metal surface is faintly illuminated the photoelectrons leave the surface immediately.

Options:
A 1, 2, 3
B 1, 2, 4
C 2, 3, 4
D 1, 3, 4

The correct answer is:
1, 3, 4

Solution:
Photoelectric effect supports quantum nature of light because
1. There is a minimum frequency of light below which no photoelectrons are emitted.
2. Maximum kinetic energy of photoelectrons depends only on the frequency of light and not on its intensity.
3. Even when the metal surface is faintly illuminated the photoelectrons leave the surface immediately.

Topic: Physics, Dual Nature of Matter, NEET
Photoelectric emission is observed from a metallic surface for frequencies n1 and n2 of the incident light rays n1>n2 . If the maximum values of kinetic energy of the photoelectrons emitted in the two cases are in the ratio of 1:k , then the threshold frequency of the metallic surface is

Options:
A n1-n2k-1
B kn1-n2k-1
C kn2-n1k-1
D n2-n1k

The correct answer is:
kn1-n2k-1

Solution:
KE1KE2=hn1-hn0hn2-hn0=1k
n0=kn1-n2k-1

Topic: Physics, Dual Nature of Matter, NEET
Photoelectric emission occurs only when the incident light has more than a certain minimum

Options:
A wavelength
B intensity
C frequency
D power

The correct answer is:
frequency

Solution:
By the concept of threshold minimum frequency needed for photoelectric emission.
$$
\begin{aligned}
\frac{1}{2} m v^2 & =h\left(v-v_0\right) \\
v & \geq v_0
\end{aligned}
$$

Topic: Physics, Dual Nature of Matter, NEET, NEET 2011 (Screening)
Photoelectric emission occurs only when the incident light has more than a certain minimum

Options:
A Power
B Wavelength
C Intensity
D Frequency

The correct answer is:
Frequency

Solution:
According to Einstein's photoelectric equation
K max = h υ - h υ 0
Since Kmax is positive, the photoelectric emission occurs only if
h υ > h υ 0 or υ > υ 0
The photoelectric emission occurs only when the incident light has more than a certain minimum frequency. The minimum frequency is called threshold frequency.

Topic: Physics, Dual Nature of Matter, NEET
Photolysis of water is associated with:

Options:
A PS I
B PS II
C Stroma lamella
D Stroma of chloroplast

The correct answer is:
PS II

Solution:
Photolysis or light-mediated breakdown of water occurs in lumen of the thylakoid. Enzyme complex responsible for photolysis of water is associated with PS II. Breakdown of water supplies electron to PS II in non cyclic photophosphorylation, liberating oxygen.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Photons of energy 1 eV and 2.5 eV successively illuminated a metal whose work function is 0.5 eV. The ratio of maximum speeds of emitted electron is

Options:
A 1 :3
B 1 :2
C 3 :1
D 2 :1

The correct answer is:
1 :2

Solution:
Energy of photon E=ϕ+12mv2
Vmax⁡ =2E-ϕm
So putting values
Vmax⁡1Vmax 2 =1-0.52.5-0.5
Vmax⁡1Vmax⁡2=12

Topic: Physics, Dual Nature of Matter, NEET
Photons of energy 6 eV are incident on a metal surface whose work function is 4 eV. The minimum kinetic energy of the emitted photoelectrons will be

Options:
A 10 eV
B 1Â eV
C 2Â eV
D zero

The correct answer is:
zero

Solution:
Kinetic energy of the emitted photoelectrons varies from zero to a maximum value.

Topic: Physics, Dual Nature of Matter, NEET
Photons of energy of 6 eV are incident on a metal surface whose work function is 4 eV. The minimum kinetic energy of the emitted photoelectrons is

Options:
A Zero
B 1 eV
C 2 eV
D 10 eV

The correct answer is:
Zero

Solution:
12mv2=hf-Ï0=hf-hf0
The kinetic energy of the emitted photoelectrons is distributed from zero to the maximum value.
minimum kinetic energy of emitted photoelectron is zero.

Topic: Physics, Dual Nature of Matter, NEET
Photons with energy of 5 eV are incident on a cathode, C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C , no photoelectrons will reach the anode, A , if, the stopping potential of A relative to C is

Options:
A +3Â V
B +4Â V
C -1Â V
D -3 V

The correct answer is:
-3 V

Solution:
Emax=E-ϕ

2 eV=5 eV-ϕ⇒ϕ=3 eV.

Now, eV0=E-ϕ

=6 eV-3 eV=3 eV.

So, the stopping potential is -3 V.

Topic: Physics, Dual Nature of Matter, NEET, NEET 2016 (Phase 2)
Photooxidation of chlorophyll is prevented by

Options:
A Carotenoid
B Anthocyanin
C Phycobilin
D Fucoxanthin

The correct answer is:
Carotenoid

Solution:
In higher plants carotenoid pigments that play active role in the xanthophyll cycle are violaxanthin, antheraxanthin, and zeaxanthin. Xanthophyll cycle is present to protect chloroplast from high intensity of sunlight.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Photoperiodic stimulus is received by

Options:
A Leaves
B Buds
C Meristem
D Flowers

The correct answer is:
Leaves

Solution:
Photoperiodic stimulus is perceived by mature-old leaves.

Topic: Biology, Plant - Growth and Development, NEET
Photosynthesis in C4 plants is relatively less limited by atmospheric CO2 levels because

Options:
A effective pumping of CO2 into bundle sheath cells
B RuBisCO in C4 plants has a higher affinity for CO2
C four-carbon acids are the primary initial CO2 fixation products
D the primary fixation of CO2 is mediated via PEP carboxylase

The correct answer is:
the primary fixation of CO2 is mediated via PEP carboxylase

Solution:
Plants that can fix atmospheric carbon dioxide into phosphoenol pyruvic acid (PEP) in the presence of the enzyme PEP carboxylase to produce oxaloacetic acid are known as C4 plants. C4 cycle is more efficient and the C4 plants can absorb carbon dioxide even in low CO2 concentration, whereas the C3 plants fail to do that.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Photosynthesis in $\mathrm{C}_4$ plants is relatively less limited by atmospheric $\mathrm{CO}_2$ levels because:

Options:
A effective pumping of $\mathrm{CO}_2$ into bundle sheath cells
B rubisco in $\mathrm{C}_4$ plants has higher affinity, for $\mathrm{CO}_2$
C four carbon acids has the primary initial $\mathrm{CO}_2$ fixation products
D the primary fixation of $\mathrm{CO}_2$ is mediated via PEP carboxylase.

The correct answer is:
effective pumping of $\mathrm{CO}_2$ into bundle sheath cells

Solution:
In $\mathrm{C}_4$ plants, initial fixation of carbon dioxide occurs in mesophyll cells. The primary acceptor of $\mathrm{CO}_2$ is phosphoenol pyruvate or PEP. It combines with carbon dioxide in the presence of PEP carboxylase or PEPcase to form oxaloacetate. $\mathrm{C}_4$ plants are more efficient in picking up $\mathrm{CO}_2$ even when it is found in low concentration because of the high affinity of PEPcase.
Related Theory
The two key restrictions slow down photosynthesis in $C_3$ cycle:
(i) Rubisco aims to fix carbon dioxide, but can also fix oxygen molecules, which creates a toxic two-carbon compound. Rubisco fixes oxygen about 20 percent of the time, initiating a process called photorespiration that recycles the toxic compound. Photorespiration costs the plant energy it could have used to photosynthesize.
(ii) When stomata are open to let carbon dioxide in, they also let water vapor out, leaving $\mathrm{C}_3$ plants at a disadvantage in drought and high-temperature environments.

Topic: Biology, Photosynthesis in Higher Plants, NEET, NEET 2005
Photosynthesis in C4 plants is relatively less limited by atmospheric CO2 levels because:

Options:
A Effective pumping of CO2 into bundle sheath cells
B Rubisco in C4 plants has higher affinity for CO2
C Four carbon acids are the primary initial CO2 fixation products
D The primary fIxation of CO2 is mediated via PEP carboxylase

The correct answer is:
The primary fIxation of CO2 is mediated via PEP carboxylase

Solution:
In C4 plants, initial fIxation of carbon dioxide occurs in mesophyll cells. The primary acceptor of CO2 is phosphoenol pyruvate or PEP. It combines with carbon dioxide in the presence of PEP carboxylase or Pepcase to form oxaloacetate.
​
C4 plants are more efficient in picking up CO2 even when it is found in low concentration because of the high affinity of PEP carboxylcase.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Photosynthesis is

Options:
A an oxidative, an exergonic, and a catabolic process.
B a redox reaction, an endergonic, and an anabolic process.
C a reductive, an exergonic, and an anabolic process.
D a reductive, an endergonic, and a catabolic process.

The correct answer is:
a redox reaction, an endergonic, and an anabolic process.

Solution:
In photosynthesis reduction of carbon dioxide and oxidation of water occurs, light energy is used hence endergonic and it is a constructive process hence anabolic.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Photosynthetic active radiation (PAR) has the following range of wavelengths:

Options:
A $340-450 \mathrm{~nm}$
B 400-700 nm
C $500-600 \mathrm{~nm}$
D $450-950 \mathrm{~nm}$.

The correct answer is:
400-700 nm

Solution:
Photosynthetically Active Radiation (PAR) is the amount of light available for photosynthesis, which is light in the 400 to 700 nanometer wavelength range.

Topic: Biology, Photosynthesis in Higher Plants, NEET, NEET 2005
Photosynthetic bacteria have pigments in

Options:
A chromatophores
B leucoplast
C chromoplast
D chloroplast

The correct answer is:
chromatophores

Solution:
The bacterial pigments and carotenoids are present in the chromatophores of the bacteria. These are pigment-containing, light-reflecting cells groups of cells. In photosynthetic bacteria, a chromatophore is a colored, pigment-containing, membranous vesicles that perform photosynthesis.

Topic: Biology, Biological Classification, NEET
Photosynthetic pigments are located on the

Options:
A inner membrane
B thylakoid membrane
C thylakoid lumen
D outer membrane

The correct answer is:
thylakoid membrane

Solution:
Thylakoids are lipoproteinaceous membrane-bound flattened discs embedded into the chloroplast stroma. The lumen or thylakoid space is present within the membrane. A stack of thylakoids in a granum resembles a stack of coins. Each thylakoid is a sac-like structure with an internal space. Two grana are interconnected by long lamellae which is called intergranum or fret channel or stroma lamellae.
The light reaction takes place in the thylakoids of grana. The thylakoid membrane is the site of photosynthesis. It contains integral and peripheral membrane protein complexes. Pigments which absorb light energy are also present on the membrane. The protein complexes and the pigments form the photosystems are also present. Thylakoid forms the third membrane system in chloroplast.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Photosynthetically active radiation (PAR) represents the following range of wavelength:

Options:
A $500-600 \mathrm{~nm}$
B $450-950 \mathrm{~nm}$
C $340-450$ tun
D $400-700 \mathrm{~nm}$.

The correct answer is:
$400-700 \mathrm{~nm}$.

Solution:
Photosynthetically Active Radiation (PAR) is the amount of light available for photosynthesis, which is light in the 400 to $700 \mathrm{~nm}$ wavelength range.

Topic: Biology, Photosynthesis in Higher Plants, NEET, NEET 2004
Phototropic and geotropic movements are linked to

Options:
A Gibberellins
B Enzymes
C Auxin
D Cytokinin

The correct answer is:
Auxin

Solution:
Phototropic movements are the plant responses towards the light. Generally, plant shoot and flower show positive phototropism while geotropism is the plant response to the gravity of earth. Generally, roots are positively geotropic. Auxin is the phytohormone which induces apical dominance and phototropic movements.

Topic: Biology, Plant - Growth and Development, NEET
Phthalic acid reacts with resorcinol in the presence of concentrated H2SO4 to give :

Options:
A Phenolphthalein
B Coumarin
C Fluorescein
D Alizarin

The correct answer is:
Fluorescein

Solution:

Topic: Chemistry, Carboxylic Acid Derivatives, NEET
Phycoerythrin is the major pigment in:

Options:
A Red algae
B Blue green algae
C Green algae
D Brown algae

The correct answer is:
Red algae

Solution:
Class

Common name

Major pigment

Chlorophyceae

Green algae

Chlorophyll a, Chlorophyll b

Phaeophyceae

Brown algae

Chlorophyll a, Chlorophyll c, Fucoxanthin

Rhodophyceae

Red algae

Chlorophyll a, Chlorophyll d, phycoerythrin, phycocyanin

Topic: Biology, Plant Kingdom, NEET, NEET 2020 (Phase 2)
Phyllode is an adaptation to

Options:
A Heterophtic environment
B Halophytic environment
C Mesophytic environment
D Xerophytic environment

The correct answer is:
Xerophytic environment

Solution:
Many xerophytes reduce the size of their leaves to minimize water loss. Such plant develop phyllodes to carry out photosynthesis. e.g. Acacia, Melanoxylon and Parkinsonia.

Topic: Biology, Morphology of Flowering Plants, NEET
Phyllode is present in:

Options:
A Asparagus
B Euphorbia
C Australian Acacia
D Opuntia

The correct answer is:
Australian Acacia

Solution:
In several species of Acacia found in the deserts of Australia the bipinnate lamina is absent. Instead petiole and part of the rachis become flattened into sickleshaped structure for performing the function of food synthesis. Such a flattened petiole which carries out the functions of the lamina is called phyllode. Formation of phyllode is a mechanism to reduce transpiration because (i) it is vertically placed and (ii) has fewer stomata.

Topic: Biology, Morphology of Flowering Plants, NEET
Phyllode is present in

Options:
A Asparagus
B Euphorbia
C Australian Acacia
D Opuntia

The correct answer is:
Australian Acacia

Solution:
The lamina in compound leaves of some plants fall off soon and petiole get modified into sickle-shaped leafy structure which performs photosynthesis. Such a modified petiole is called phyllode. Phyllodes develop usually vertically and possess fewer stomata hence, reduce transpiration, e.g., Australian Acacia, Parkinsonia, etc.

Topic: Biology, Morphology of Flowering Plants, NEET, NEET 2012 (Screening)
Phyllode is present in

Options:
A Asparagus
B Euphorbia
C Australian Acacia
D Opuntia

The correct answer is:
Australian Acacia

Solution:
Phyllode is present in Australian Acacia. It is a modification of leaf in which lamina is absent and petiole becomes flattened and perform the function of food synthesis.

Topic: Biology, Morphology of Flowering Plants, NEET
Phylogenetic system of classification is based on

Options:
A evolutionary relationships
B morphological features
C chemical constituents
D floral characters

The correct answer is:
evolutionary relationships

Solution:
Phylogenetic system classifies the plants according to their evolutionary and genetic relationships, eg, Eichler's. Engler and Prantl's Systems of classification.

Topic: Biology, The Living World, NEET, NEET 2009 (Screening)
Phylum	Level of organization	Digestive system	Respiratory system

Aschelminthes	A	Complete	Absent

Echinodermata	Organ system	B	Present

Platyhelminthes	Organ	Incomplete	C

Annelida	Organ system	Incomplete	D

Select the option with correct identification of A, B, C, and D.

Options:
A A - organ, B - Complete, C-Present, D - Absent
B A - organ system, B - Complete , C - Absent , D - Absent
C A - organ system, B - Incomplete , C - Absent , D - Present
D A - organ system, B - Incomplete , C - Present , D - Absent

The correct answer is:
A - organ system, B - Complete , C - Absent , D - Absent

Solution:
I. Levels of the organization - It is of various types
A. Cellular level - Division of labour is there between the cells but are not tissues. These are in the form of loose cell aggregates. Example: Sponges (Porifers)
B. Tissue level - Cells that are organized to perform the same function act as tissues. Examples: Coelenterates.
C. Organ level - Tissues grouped together to form organs. Examples: Platyhelminthes.
D. Organ system level - Organs associated to form functional systems. Examples: Annelids, arthropods, molluscs, echinoderms, and chordates.
II. Digestive system is
A. Incomplete with a single opening (blind sac body plan) that acts as anus and mouth both. e.g. Coelenterates and Platyhelminthes.
B. Complete with two openings (tube within tube plan) which behave as anus and mouth separately. e.g. from Aschelminthes up to Chordates.
III. Specific respiratory structures and respiratory system is well developed from phylum Arthropoda.

Topic: Biology, Animal Kingdom, NEET
Phylum Mollusca is characterized by

Options:
A Diploblastic, Bilaterally symmetrical Coelomates
B Triploblastic, Bilaterally symmetrical, Pseudocoelomates
C Triploblastic, Bilaterally symmetrical, Coelomates
D Diploblastic Radially symmetrical, Acoelomates

The correct answer is:
Triploblastic, Bilaterally symmetrical, Coelomates

Solution:
Molluscs are triploblastic, bilaterally symmetrical coelomates. In some Molluscs like Pila, due to torsion during growth, the adults become asymmetrical. The coelom is greatly reduced. It is restricted to the pericardial cavity (space around the heart), and to small spaces within kidneys and gonads (testes and ovaries). Spaces amongst the viscera (soft organs) contain blood and form hemocoel. They have triploblastic body wall with outer ectoderm middle mesoderm and inner endoderm.

Topic: Biology, Animal Kingdom, NEET
Phylums and related characteristics are given below. Choose an appropriate option which fills the blank spaces.

PHYLUM/CLASS	EXCRETORY ORGANS	CIRCULATORY ORGANS	RESPIRATORY ORGANS

1	Arthropoda	A	Open	Trachae

2	B	Metanephridia	Open	Gills

3	Amphibia	C	Closed	D

Options:
A A: Nephridia, B: Echinodermata, C: Metanephridia, D: Lungs
B A: Flame cells, B: Annelida, C: Metanephridia, D: Book gills
C A: Malphigian, B: Mollusca, C: Metanephridia, D: Book gills
D A: Malphigian tubules, B: Mollusca, C: Kideny, D: lung

The correct answer is:
A: Malphigian tubules, B: Mollusca, C: Kideny, D: lung

Solution:
The excretory organs of arthropoda are: Nephridia, Coxal Glands, Green Gland, Malpighian Tubules with open circulatory system. They respire by the help of Trachae/book lungs
Mollucs also have a well developed excretory system, using tubular nephridia organized as kidneys. They respire by the help of gills which are also called as ctenidia.
Amphibia possess two kidneys located dorsally, in the body cavity which helps in excretion of waste. They have tails gills/gills for respiration in larval stages while lungs in adult.

Topic: Biology, Animal Kingdom, NEET
Physical properties in which D2O differ from H2O is/are-

Options:
A Solubility of salts in heavy water is less than ordinary water.
B all physical constants of D2O are higher than H2O.
C heavy water is 11% lighter than normal water.
D all of the above

The correct answer is:
all of the above

Solution:
Correct Option is : 4
all of the above

Topic: Chemistry, Hydrogen, NEET
Physiological barriers prevent microbial growth in our human body include all, except

a. Tears
b. Skin
c. Interferons
d. Saliva
e. Acid in stomach
f. Epithelium of urinogenital tract

Options:
A a,Â bÂ &Â f
B a,Â dÂ &Â e
C c,Â eÂ &Â f
D b, c & f

The correct answer is:
b, c & f

Solution:
There are two types of immunity: innate and acquired immunity. Innate immunity is present since birth, including many barriers like physical, physiological, cellular and chemical etc. Barriers are essential as they prevent microbes from entering our bodies. These form the essential first line of defense. Physiological barriers include those acids in the stomach, tears from eyes, saliva in the mouth etc. Skin is a physical barrier, while interferons are cellular barriers.

Topic: Biology, Human Health and Diseases, NEET
Physiological barriers that prevent microbial growth exclude

Options:
A Mucus in urinogenital tract
B Acid in stomach
C Saliva in mouth
D Tears in eyes

The correct answer is:
Mucus in urinogenital tract

Solution:
Barriers important that prevent microbes to enter are: Physiological barriers, Chemical barriers and cellular barriers. These are anatomical barriers. These form the important first line of defense. These provide innate immunity. These include Saliva, tears, gastric juice, trypsin, sebum, lactoferrin etc.

Topic: Biology, Human Health and Diseases, NEET
Phytoalexins are secreted by plants in response to fungal reaction. These compounds are generally

Options:
A Proteins
B Glycoproteins
C Phenolic compounds
D Lipids

The correct answer is:
Phenolic compounds

Solution:
Phytoalexins are phenolic compounds produce in the host cell for defense in response to fungal infection. These chemicals inhibit the growth of the parasite by disturbing the metabolism or normal development of larva or reducing the digestibility of plant.

Topic: Biology, Organisms and Populations, NEET
Phytochrome is a:

Options:
A Flavoprotein
B Glycoprotein
C Lipoprotein
D Chromoprotein

The correct answer is:
Chromoprotein

Solution:
Borthwick and Hendrick in 1952 reported the presence of a photoreceptive pigment called phytochrome, a bluish-green coloured compound isolated from the plasma membrane of alga.
There are two types of phytochromes in plants, named as phytochrome-red (Pr) and phytochrome-far-red (Pfr). The Pr is called as 660 nm absorbing form and the Pfr is 740 nm absorbing form. These two forms are inter-convertible, that means, Pr can be converted into Pfr. The Pr can be converted into Pfr if it is exposed to red light, which is faster. Similarly, the Pfr can be converted into Pr if it is exposed to far-red light, which is slow. Since, it has colour, it is called as a chromoprotein.

Topic: Biology, Photosynthesis in Higher Plants, NEET, NEET 2016 (Phase 2)
Phytochrome is involved in

Options:
A phototropism.
B photorespiration.
C photoperiodism.
D geotropism.

The correct answer is:
photoperiodism.

Solution:
Phytochrome is a photoreceptor molecule which mediates several developmental and morphogenetic responses of plants to light. This is called photoperiodism. Borthwick, Hendicks and Parker in 1952, discovered phytochrome, which is a pigment that received light and existed in two inter convertible forms: active form and inactive form, Pr and Pfr.

Topic: Biology, Plant - Growth and Development, NEET