All India Aakash Test Series for NEET - 2020 · 2020. 4. 7. · All India Aakash Test Series for NEET-2020 Open Mock Test-4 (Code-A)_(Hints & Solutions) Aakash Educational Services
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Open Mock Test-4 (Code-A)_(Answers) All India Aakash Test Series for NEET-2020
[PHYSICS] 1. Answer (2) Hint : If two vector are perpendicular then their dot
product should be zero.
Sol. : Let ˆ ˆr ai bj= +
ˆ ˆ ˆ ˆ( ) (3 4 ) 0ai bj i j+ ⋅ + =
34ab = −
2 2 10a b+ =
2
2 3 1004aa + − =
a = 8
3 84
b = − ×
b = –6
ˆ ˆ8 6r i j= −
2. Answer (2) Hint & Sol. : Density of electric field lines indicate
the relative magnitude of charge. From positive charge, electric field lines are radially outward, while for negatively charged particle, electric field lines are radially inwards.
3. Answer (4) Hint and Sol. : Inside a conducting plate, the electrostatic field is
zero. While outside conducting plate, electrostatic field would be uniform.
4. Answer (3)
Hint : −∂ ∂ ∂= − −
∂ ∂ ∂ˆ ˆ ˆ U U UF i j k
x y z.
Sol. :
( ) ( ) ( )2 2 22 2 2
ˆ ˆ ˆ−∂ + ∂ + ∂ +
= − −∂ ∂ ∂
xyz x xyz x xyz xF i j k
x y z
( ) ( ) ( )2 2ˆ ˆ ˆ2 1 2 4= − + − −
F yz i xz j xyz k
At origin ( )ˆ1 N= −
F i
5. Answer (2) Hint : Series and parallel combination.
10. Answer (1) Hint : Lenz’s Law. Sol. : As current in loop A increases, the flux
through loop B would increase. As per the Lenz’s law, the loop B would tend to move away from loop A i.e. rightwards. Thus, a force towards left must be applied.
11. Answer (4)
Hint : Current ( ) dQidt
= and = ∫ 2H i Rdt
Sol. : 2 12= = −dQi tdt
( )22 2 12 2H i R dt t dt= = −∫ ∫
1
2
02 (4 144 48 )
= + −
∫ t t dt
1 1 1
2
0 0 02 4 144 48
= + −
∫ ∫ ∫dt t dt tdt
144 482 43 2
= + −
= 8 + 96 – 48 = 56 J 12. Answer (2)
Hint : ( )2 22 f i
Be R Rω= − .
Sol. : ( )2 202 2
B Be a aω ω= − =
13. Answer (4) Hint & Sol. : For A = 0, B = 1 and C = 1, Y = 0 14. Answer (1) Hint & Sol. : Electromagnetic spectrum in order of
increasing frequency and decreasing wavelength is
Radiowaves – Microwaves – Infrared – Visible – Ultravoilet – X ray – Gamma rays
15. Answer (4) Hint : Normal force by wall of tube provides
necessary centripetal force to a small element of water while normal force by water on the wall of tube leads to develop tension in it.
Sol. :
Centripetal force dN = 2Tsinθ 2( )
=dm v
R
2
2 sin= θv dm T
R
= π θ ρ
2
(2 )2ddm R
As θ → θ = θ0 sin
π θ ρ
= = πρθ
22
2 2(2 ) 14
2 sin 4
dv RT v d
R
16. Answer (1) Hint : Tangential acceleration will be zero if
[L T–1] = [Ma+c L2a+b+c T– a – 2c] a + c = 0 2a + b + c = 1 – a – 2c = – 1 ⇒ a + 2c = 1 ⇒ a = –1, b = 2, c = 1 37. Answer (2) Hint : Pulley – mass systems Sol. : acceleration (a) of blocks
mobilisation. Gibberellin → Stem elongation in sugarcane. Ethylene → Induce flowering in pineapple. ABA → Closure of stomata. 116. Answer (1) Hint : Rhizome, bulbil and offset are vegetative
propagules. Sol. : Conidia is asexual, non-motile spore in
Penicillium. 117. Answer (2) Sol. : Strobilanthus kunthiana flowers once in
every 12 years. 118. Answer (2) Hint : Hydrophily is restricted to 30 genera of
monocots only. Sol. : Aquatic plants like water hyacinth and
water lily are insect pollinated plants. 119. Answer (1) Hint : Legumes are non-albuminous. Sol. : Pea and groundnut have non-albuminous
seeds. 120. Answer (4) Sol. : Phenotypes in dihybrid test cross.
121. Answer (4) Hint : Given pedigree is not applicable for sex
linked recessive disorders. Sol. : Haemophilia being X-linked recessive
disorder, is not applicable in above pedigree. 122. Answer (2) Hint : RNA is less stable than DNA. Sol. : DNA is less reactive and more stable
hence preferred as genetic material. 123. Answer (2) Hint : In eukaryotes the monocistronic structural
genes have interrupted coding sequences. Sol. : Split genes are present in eukaryotes.
Expressed sequences are known as exons. 124. Answer (3) Sol. : Himgiri – Resistant to leaf and stripe rust,
hill bunt. Parbhani Kranti – Resistant to yellow mosaic virus. Pusa Shubhra – Resistant to black rot and curl. Pusa Komal - Resistant to bacterial blight. 125. Answer (4) Sol. : Totipotency is generation of whole plant
from a single cell/explant. 126. Answer (1) Sol. : Aspergillus niger → citric acid
Acetobacter → Acetic acid Clostridium → butyric acid Trichoderma → Cyclosporin A. 127. Answer (4) Hint : Ladybirds are used to control aphids. Sol. : Baculoviruses are species specific.
Trichoderma is a biocontrol agent . 128. Answer (1) Sol. At high altitude, binding affinity of ‘Hb to
oxygen decreases. 129. Answer (2) Hint : Visiting flamingos and resident fishes
requires the same food. Sol. : Both fight for the same resources thus they
show competition. 130. Answer (2) Hint : Stratification and anabolism do not occur
during decomposition. Sol. : Steps of decomposition – Fragmentation,
(Vertebrates), Fungi (plants) show maximum biodiversity.
133. Answer (4) Hint : ‘The Evil Quartet’ are habitat loss and
fragmentation, over exploitation, alien species invasion, co-extinction.
Sol. : Co-evolution is not an Evil Quartet rather it is related to mutualism.
134. Answer (2) Sol. : Environment (Protection) act was given in
1986. 135. Answer (1) Hint : CO2 has the maximum global warming
potential. Sol. : Correct sequence of green house gases
are N2O (6%) < CFCs (14%) < CH4 (20%) < CO2 (60%). 136. Answer (2) Hint : Mast cells secrete a variety of inflammatory
mediators. Sol. : Inflammation is triggered by release of
chemicals such as histamine and kinins by mast cells and damaged cells.
137. Answer (2) Hint : This was developed by Calmette and
Guerin. Sol. : BCG is a vaccine against tuberculosis that
is prepared from a strain of attenuated live bovine tuberculosis bacillus. It loses its virulence considerably by being subcultured in an artificial medium for years.
138. Answer (4) Hint : Polio drops provide artificial active immunity. Sol. : Attenuated (i.e. live organisms that are
weakened to eliminate their virulence) poliovirus was used by Albert Sabin to develop oral vaccine for polio.
139. Answer (4) Hint : Fatty fish are rich in omega 3 fatty acids. e.g.
sardines and herring. Sol. : Edible marine fishes are Hilsa, Anguilla,
Sardinella. Mystus, Magur and Mrigala are fresh water fishes.
140. Answer (4) Hint : Phosphodiester bonds are present in DNA. Sol. : Insulin consists of 51 amino acids and is one
of the smallest proteins in the human body. It contains two polypeptide chains A and B linked by disulfide bonds.
141. Answer (1) Hint : Nyctalopia is night blindness. Sol. : Golden rice contains beta carotene gene
from daffodil plants. Beta carotene is precursor of vitamin – A.
142. Answer (2) Hint : These cells are pyramidal in appearance. Sol. : Large non-dividing Sertoli cells function as
supportive cells for developing sperms. Leydig cells are present in connective tissue around seminiferous tubules.
143. Answer (3) Hint : This is an Australian marsupial. Sol. : Australian marsupials and placental
mammals show convergent evolution. 144. Answer (3) Hint : Fetal cells can be analysed by
amniocentesis. Sol. : Amniocentesis is based on chromosomal
pattern (Karyotype) to determine genetic makeup of the developing foetus.
145. Answer (3) Hint : ZIFT stands for zygote intrafallopian
transfer. Sol. : In ZIFT, the early embryo is transferred in
the 8 blastomere stage in the fallopian tube of the mother.
146. Answer (2) Hint : Cranial capacity of modern day man is 1450
cc. Sol. : Neanderthal man is considered to be very
close to modern day man in line of ancestry. 147. Answer (3) Hint : Interferons are produced against virus
particles. Sol. : Measles is caused by a single stranded
enveloped virus spread by coughing and sneezing.
148. Answer (3) Hint : Mycobacterium leprae and Mycobacterium
tuberculosis are the two different species of Mycobacterium.
Sol. : Mycobacterium tuberculosis causes tuberculosis and M. leprae causes leprosy.
Open Mock Test-4 (Code-A)_(Hints & Solutions) All India Aakash Test Series for NEET-2020
programs in India and makes decisions regarding the validity of GM research and the safety of introducing GM organisms in India.
152. Answer (1) Hint : This spot has only cones and is a
depression in retinal wall. Sol. : Yellow spot or macula lutea has only cone
cells filled with a yellow pigment. It is the area of most acute vision in the eye where sharp and bright vision is formed. Region ‘D’ is blind spot with neither rods nor cones.
153. Answer (4) Hint : Neuroendocrine organ of the body. Sol. : Hypothalamus is the centre for hunger,
thirst, sweating, sleep, fatigue, temperature (thermoregulation) etc.
154. Answer (4) Hint : This bacteria can cause food poisoning. Sol. : Clostridium tetani causes tetanus which is
also known as lock jaw. Clostridium botulinum causes botulism.
155. Answer (4) Hint : It stimulates excretion of sodium and water
by the kidneys. Sol. : ANF is a peptide hormone produced by the
right atrium of the heart. It is produced in response to increased blood pressure.
156. Answer (2) Hint : It is the chief nitrogenous waste product of
humans. Sol. : Urea is maximum in concentration in hepatic
vein. Hepatic vein drains blood from liver into post caval vein. Urea is minimum in renal vein.
157. Answer (2) Hint : Maximum ventricular filling occurs during
atrial diastole.
Sol. : Majority of ventricular filling occurs when both ventricles and atria are relaxing. In atrial systole about 30% filling occurs.
158. Answer (4) Hint : Members of this phylum have dorsoventrally
flattened body. Sol. : Flame cells are specialized excretory
structures found in simple freshwater invertebrates, flatworms and rotifers.
159. Answer (4) Hint : It functions as a hydrostatic skeleton in
some lower animals. Sol. : Mesoglea is a translucent, non-living jelly
like substance found between two epithelial cell layers in the bodies of cnidarians. It is comparable to mesohyl of sponges.
160. Answer (2) Hint : Eyes of many arthropods are compound
eyes with mosaic vision. Sol. : Ommatidia are units in the eye of a
cockroach and each of it functions as a separate visual receptor.
161. Answer (4) Hint : Function of hepatic caecae is to secrete
digestive juices. Sol. : In cockroach (Periplaneta) a ring of 6 – 8
blind tubules called hepatic caecae are present at the junction of foregut and midgut.
162. Answer (4) Hint : RNA molecules. Sol. : Almost all enzymes are proteins, however,
certain RNA molecules called ribozymes (e.g. ribonuclease – P) directly act as enzymes.
163. Answer (4) Hint : ATP is adenosine triphosphate – the energy
currency of the cell. Sol. : ATP consists of three phosphate groups
attached to adenosine. Energy transfer typically involves hydrolysis of the last phosphate bond of ATP.
164. Answer (3) Hint : Km is the Michaelis – Menten constant. Sol. : Km shows the concentration of the substrate
when the velocity of the reaction is equal to one half of the maximal velocity of the reaction.
165. Answer (2) Hint : Bile contains no digestive enzymes. Sol. : Hepatocytes use cholesterol to make bile
salts.
All India Aakash Test Series for NEET-2020 Open Mock Test-4 (Code-A)_(Hints & Solutions)
166. Answer (4) Hint : Laetrile is a partly man made vitamin. Sol. : Laetrile is a synthetic form of amygdalin
which is found naturally in raw nuts. Laetrile is called Vit B17 although it is not a true
vitamin. Vitamin D2 is ergocalciferol, Vitamin E is tocopherol. 167. Answer (2) Hint : FRC is the functional residual capacity. Sol. : FRC = ERV + RV = 1100 + 1200 = 2300 ml 168. Answer (2) Hint : Glomerular filtrate lacks proteins
responsible for maintaining osmolarity of blood. Sol. : Plasma fluid that filters out from glomerular
capillaries into Bowman’s capsule of nephrons is called glomerular filtrate.
169. Answer (3) Hint : Visceral wall of Bowman’s capsule. Sol. : Podocytes are found on the inner wall of
Bowman’s capsule and make slit pores. They prevent / restrict passage of colloids.
170. Answer (4) Hint : It is the region between two
Z – lines. Sol. : Z – line or Krause’s membrane divides the
myofibrils into functional units called sarcomeres. 171. Answer (2) Hint : ADH is also known as vasopressin. Sol. : Diabetes insipidus is characterized by
diuresis due to deficiency of antidiuretic hormone. Grave’s disease is also known as exopthalmic goitre.
172. Answer (4) Hint : It secretes progesterone. Sol. : Corpus luteum functions as a temporary
endocrine gland secreting progesterone. 173. Answer (3) Hint : Haploid cell stage is reached after meiosis.
174. Answer (3) Hint : Norplant is surgically implanted under the
skin. Sol. : Norplant contains progestin as an active
ingredient and slowly releases the hormone to block ovulation and implantation.
175. Answer (1) Hint : Gene flow causes arrival of new alleles. Sol. : Maintenance of Hardy Weinberg equilibrium
requires absence of genetic drift, gene flow or migrations.
176. Answer (4) Hint : Mother’s milk provides natural passive
immunity. Sol. : Nursing mothers transfer IgA antibodies
through milk (colostrum) to the infants. 177. Answer (3) Hint : cry genes are of various types. Sol. : cryIAc and cryIIAb controls cotton
bollworms, dipterans like flies and coleopterans such as beetles.
cryIAb controls corn borer. 178. Answer (3) Hint : Pseudomonas genus has been modified to
control oil spills. Sol. : Pseudomonas putida is used in scavenging
of oil spills by digesting hydrocarbons of crude oil. 179. Answer (3) Hint : Cortisol is considered a life saving hormone. Sol. : Cortisol inhibits the normal defense
mechanisms and mobilises help from all parts of body to sustain life. It works in stress and shock situations.
180. Answer (4) Hint : Embryonic care is greatest in viviparous
animals. Sol. : Due to proper embryonic care and
protection, the chances of survival of young ones are greatest in viviparous animals.