datavorous/entrance-exam-dataset huggingface dataset:
A flux of 1 mWb passes through a strip having an area A=0.02 m2. The plane of the strip is at an angle of 60Â° to the direction of a uniform field B. The value of B is

Options:
A 0.1Â T
B 0.058 T
C 4.0Â mT
D none of the above.

The correct answer is:
0.058 T

Solution:
We know that, ϕ=BAcos⁡θ
Angle between A→ and B→ is 30°.
ϕ=1×10-3 Wb
A=0.02 m2
⇒10-3=B×2×10-2×cos⁡30o
⇒B=0.058 T

Topic: Physics, Electromagnetic Induction, NEET
A flux of 10-3 Wb passes through a strip having an area A=0.02 m2. The plane of the strip is at an angle of 60Â° to the direction of a uniform field B. The value of B is

Options:
A 0.1Â T
B 0.058 T
C 4.0Â mT
D none of the above

The correct answer is:
0.058 T

Solution:
As the angle between field and plane is 60o, therefore angle between area vector and magnetic field is,
Î¸=30o
Magnetic flux through the strip is
Ï=BAcosâ¡Î¸
10-3=B0.02cosâ¡30o
B=10-30.0232
B=0.058 T

Topic: Physics, Electromagnetic Induction, NEET
A flywheel at rest is to reach an angular velocity of 24 rad s-1 in 8 s with constant angular acceleration. The total angle turned through during this interval is

Options:
A 24 rad
B 48 rad
C 72 rad
D 96 rad

The correct answer is:
96 rad

Solution:
ω0=0, ω=24 rad s-1, t=8 s
∴ α=ω-ω0t=248=3 rad s-2
θ=ω0t+12αt2
=0+12×3×82
=3×642=96 rad.

Topic: Physics, Laws of Motion, NEET
A flywheel of the moment of inertia 0.4 kg m2 and radius 0.2 m is free to rotate about a central axis. If a string is wrapped around it and it is pulled with a force of 10 N, then its angular velocity after 4 s will be

Options:
A 10 rad s-1
B 5 rad s-1
C 20 rad s-1
D None of these

The correct answer is:
20 rad s-1

Solution:
F×r=Iα=I(ω2-ω1)t
∴ ω2-ω1=F×r×tI
=10×0.2×40.4=20 rad s-1

Topic: Physics, Rotational Motion, NEET
A flywheel rotates about a fixed axis and slows down from 300 rpm to 100 rpm in 2 min. Then its angular retardation in radmin-2 is

Options:
A 100Ï
B 100
C 100Â Ï
D 200 Ï

The correct answer is:
200 Ï

Solution:
Because of uniform angular acceleration. we can use the equation of motion in rotation.
α=ω2-ω1t=2π100-3002= -200 π rad min-2

Topic: Physics, Laws of Motion, NEET
A football is kicked into the air vertically upwards. What is its accelerationat the highest point?

Options:
A 0
B -9.8 m/s²
C 9.8 m/s²
D 1 m/s²

The correct answer is:
9.8 m/s²

Solution:
Correct Option is : (C)
9.8 m/s²

Topic: Chemistry, Motion In Two Dimensions, NEET
A football player is moving southward and suddenly turns eastward with the same speed to avoid an opponent. The force that acts on the player while turning is :

Options:
A along south-west
B along eastward
C along northward
D along north-east

The correct answer is:
along north-east

Solution:
Let the speed of the football player be, v.

Then, we can write

v→i=v-j^ and v→f=vi^.

We can write force as,

F→=ma→=mv→f-v→it=mvti^+j^

Clearly, the direction of the force acting will be towards north-east.

Topic: Physics, Motion In One Dimension, NEET, NEET 2023 (All India)
A force acts on a 30 g particle in such a way that the position of the particle as a function of time is given by x=3t-4t2+t3 where x is in meters and t is in seconds. The work done during the first 4 seconds is

Options:
A 5.28 J
B 450Â mJ
C 490Â mJ
D 530Â mJ

The correct answer is:
5.28 J

Solution:
v=dxdt=3-8t+3t2
Speed at t=0 is
v0=3 m/s
Speed at t=4 is
v4=19 m/s
According to work energy theorem
W=12mv42-v02
W=12Ã0.03Ã192-32=5.28 J

Topic: Physics, Work Power Energy, NEET
A force defined by $F=\alpha t^2+\beta t$ acts on a particle at a given time $t$. The factor which is dimensionless, if $\alpha$ and $\beta$ are constants, is:

Options:
A $\alpha t / \beta$
B $\alpha \beta t$
C $\alpha \beta / t$
D $\beta t / \alpha$

The correct answer is:
$\alpha t / \beta$

Solution:
From principle of homogeneity
$\begin{aligned}
& {[F]=\left[\alpha t^2\right]=[\beta t]} \\
& {[\alpha]=\frac{[F]}{\left[t^2\right]} \text { and }[\beta]=\frac{[F]}{[t]}} \\
& \therefore \quad[\alpha][t]=[\beta] \\
& \therefore \quad \frac{\alpha t}{\beta}=\text { dimensionless }
\end{aligned}$

Topic: Physics, Units and Dimensions, NEET, NEET 2024
A force F â = 2 i ^ + 3 j ^ N is applied to an object that is pivoted about a fixed axle aligned along the z-coordinate axis. If the force is applied at the point r â = 4 i ^ + 5 j ^ m, then the magnitude of the net torque about the z-axis is

Options:
A 4
B 1
C 2
D 10

The correct answer is:
2

Solution:
F → = 2 i ^ + 3 j ^ N
r→=4i^+5j^ m ⇒ τ→=r→×F→
τ → = 4 i ^ + 5 j ^ × 2 i ^ + 3 j ^
τ → = 1 2 k ^ - 1 0 k ^ ⇒ τ → = 2 k ^

Topic: Physics, Rotational Motion, NEET
A force F=2i^+4 j^Newton displaces the body by s=3j^+5k^ meter in 2 s. The power generated will be

Options:
A 11 W
B 6 W
C 22 W
D 12 W

The correct answer is:
6 W

Solution:
Work done is given by
F⋅s=2i^+4j^⋅(3j^+5k^) =12 j^
Now, power=worktime=122=6 W

Topic: Physics, Work Power Energy, NEET
A force F=2t2 is applied to the cart initially at rest. The speed of cart at t=5 s is -

Options:
A 10 m s-1
B 8.33 m s-1
C 2 m s-1
D zero

The correct answer is:
8.33 m s-1

Solution:
F=2t2
⇒mdvdt=2t2
⇒10∫0vdv=2∫05t2dt
⇒10v=2t3305
⇒v=8.33 m s-1

Topic: Physics, Laws of Motion, NEET
A force F=5i^+3j^ N is applied over a particle which displaces it from its origin to the point r=2i^-1j^ m. The work done on the particle is

Options:
A -7 J
B +13 J
C +7 J
D +11 J

The correct answer is:
+7 J

Solution:
W=Fâ.sâ
W=5i^+3j^.2i^-2j^
W=10-3=7 J

Topic: Physics, Work Power Energy, NEET
A force F=20+10y acts on a particle in y-direction where F is in Newton and y is in meter. Work done by this force to move the particle from y=0 to y=1 m is

Options:
A 30 J
B 5 J
C 25 J
D 20 J

The correct answer is:
25 J

Solution:
Work done is calculated by taking the dot product between the force and the displacement.

W=∫F·dy
=∫0120 dy+∫0110 y dy
=20 y01+5y201
=20+5=25 J

Topic: Physics, Work Power Energy, NEET, NEET 2019 (All India)
A force F = 75 N is applied on a block of mass 5 kg along the fixed smooth incline as shown in the figure. Here gravitational acceleration g=10 m s-2. The acceleration of the block is

Options:
A 10 m s-2 downwards the incline
B 10 m s-2 upwards the incline
C 5 m s-2 downwards the incline
D 5 m s-2 upwards the incline

The correct answer is:
10 m s-2 upwards the incline

Solution:
Consider the force acting on the block as shown below
Given, F=75 N
m=5 kg
Acceleration of the block
F-mgsinâ¡30o=ma
â a=F-mgsinâ¡30om
â a=75-5gsinâ¡30o5
a=505=10 m s-2 upwards the inclined plane

Topic: Physics, Laws of Motion, NEET
A force Fâ=ai^+3j^+6k^ is acting at a point râ=2i^- 6j^- 12k^. The value of a for which angular momentum is conserved is -

Options:
A 0
B 1
C - 1
D 2

The correct answer is:
- 1

Solution:
Angular momentum will be conserved if τ=0
i.e. r→ × F→=0
a2=3-6=6-12
∴ a=- 1

Topic: Physics, Rotational Motion, NEET
A force F acting on a body depends on its displacement s as Fâs-1/3. The power delivered by F will depend on displacement as

Options:
A s23

B s-53
C s12
D s0

The correct answer is:
s0

Solution:
F â s -1 / 3
i.e., acceleration a â s - 1 / 3
or v dv ds = Ks - 1 / 3 or v 2 â s 2 / 3
or v â s 1 / 3
Now P = F . v
or P â s - 1 / 3 . s 1 / 3 or P â s 0
i.e., power is independent of s.

Topic: Physics, Work Power Energy, NEET
A force F acting on a body depends on its displacement s as Fâs-1/3. The power delivered by F will depend on displacement as

Options:
A s23

B s-53
C s12
D s0

The correct answer is:
s0

Solution:
F∝s-1/3
i.e., acceleration a∝s-1/3
or vdvds=Ks-1/3 or v 2 ∝ s 2 / 3
or v∝s1/3
Now P=F.v
or P∝s-1/3. s1/3 or P∝s0
i.e., power is independent of s.

Topic: Physics, Work Power Energy, NEET
A force $F$ acting on an object varies with distance $x$ as shown here. The force is in $N$ and $x$ in $\mathrm{m}$. The work done by the force in moving the object $x=0$ to $x=6 \mathrm{~m}$ is:

Options:
A $18.0 \mathrm{~J}$
B $13.5 \mathrm{~J}$
C $9.0 \mathrm{~J}$
D $4.5 \mathrm{~J}$

The correct answer is:
$13.5 \mathrm{~J}$

Solution:
Work done $=$ Area under $=f-x$ curve.
$$
\begin{aligned}
& =\text { area of trapezium }=\frac{1}{2} \times(6+3) \times 3 \\
& =\frac{27}{2}=13.5 \mathrm{~J}
\end{aligned}
$$

Topic: Physics, Work Power Energy, NEET, NEET 2005
A force F→=αi^+3j^+6k^ is acting at a point r→=2i^-6j^-12k^ . The value of α for which angular momentum about origin is conserved is:

Options:
A 2
B Zero
C 1
D −1

The correct answer is:
−1

Solution:
If L→= constant then τ→=0
So r→×F→=0⇒F→ should be parallel to r→ so coefficient should be in same ratio. So α2=3-6=6-12
So α=-1

Topic: Physics, Rotational Motion, NEET, NEET 2015 (Phase 2)
A force F→=αi^+3j^+6k^ is acting at a point r→=2i^-6j^-12k^ . The value of α for which angular momentum about origin is conserved is:

Options:
A 2
B Zero
C 1
D −1

The correct answer is:
−1

Solution:
If L→= constant then τ→=0
So r→×F→=0⇒F→ should be parallel to r→ so coefficient should be in same ratio. So α2=3-6=6-12
So α=-1

Topic: Physics, Rotational Motion, NEET
A force F is related to the position of a particle by the relation F = (10x2) N. The work done by the force when the particle moves from x = 2 m to x = 4 m is

Options:
A 5 6 3 J
B 560 J
C 5 6 0 3 J
D 3 5 6 0 J

The correct answer is:
5 6 0 3 J

Solution:
W=â«24Fdx=â«2410x2dâ¡x=10x3324
= 1 0 3 4 3 - 2 3 = 1 0 3 Ã 5 6 = 5 6 0 3 J

Topic: Physics, Work Power Energy, NEET
A force F⁡ → = - K⁡ y⁡ i ^ + x⁡ j ^ (where K is a positive constant) acts on a particle moving in the x-y plane. Starting from the origin, the particle is taken along the positive x-axis to the point (a,0) and then parallel to the y-axis to the (a,a). The total work done by the force F⁡ → on the particle is

Options:
A -2Ka2
B 2Ka2
C -Ka2
D Ka2

The correct answer is:
-Ka2

Solution:
F=-Kyi^+xj^
On moving from origin to (a, 0).
Work done=∫0a-Kyi^+xj^.dx
= 0
as y = 0
Work done from (a, 0) to (a, 0)
Work done w=∫0a-Kyi^+xj^dy but x = a
= ∫ 0 a - K a dy
= - Ka 2

Topic: Physics, Work Power Energy, NEET
A force given by F â = f x i ^ + f y j ^ + f z k ^ acts on a particle which moves from a,b,c to d,e,f . The work done by the force F is : (Here A1,A2,A3 are magnitude of area bounded)

Options:
A A1+A2+A3
B A1-A2-A3
C -A1+A2-A3
D A1-A2+A3

The correct answer is:
A1-A2-A3

Solution:
w=â«abfxdx+â«befydy+â«cffzdz
Now â« a d f x dx is positive since f x > 0 and d > a
â« b e f y dy in negative since f y > 0 ; e < b
â« c f f z dz is negative f z < 0 ; f > c
â´ w=A1-A2-A3

Topic: Physics, Mathematics in Physics, NEET
A force is given by F=at+bt2 where t is time. The dimensions of a and b are

Options:
A MLT - 4 , MLT - 2
B MLT - 3 , MLT - 4
C ML 2 T - 3 , ML 2 T - 2
D ML 2 T - 3 , ML 2 T - 4

The correct answer is:
MLT - 3 , MLT - 4

Solution:
Dimension of at = Dimension of F
at = F
a = F t
a = MLT - 2 T
a = MLT - 3
Dimension of bt 2 = Dimension of F
bt 2 = F
b = F t 2
b = MLT - 2 T 2
b = MLT - 4

Topic: Physics, Units and Dimensions, NEET
A force of ( 7i^+6k^ ) N makes a body move on a rough plane with a velocity of ( 3j^+4k^ ) m s-1. The power (in watt) delivered by the force is

Options:
A 24
B 34
C 21
D 45

The correct answer is:
24

Solution:
Power, Pâ¡=FâÂ·vâ

âP=7i^+6k^.3j^+4k^=24 W

Topic: Physics, Work Power Energy, NEET
A force of 100 dyne acts on a mass of 5 g for 10 s. The velocity produced is

Options:
A 2 cm s-1
B 20 cm s-1
C 200 cm s-1
D 2000 cm s-1

The correct answer is:
200 cm s-1

Solution:
Given,
F=100 dyne
m=5 gram
t=10 second
Acceleration a=Fm=1005=20 cm/s2
Now from equation of motion
v=u+at
v=0+20×10
v=200 cm/s

Topic: Physics, Laws of Motion, NEET
A force of -Fk^ acts on O, the origin of the coordinate system. The torque about the point ( 1, -1 ) is

Options:
A -Fi^-j^
B Fi^-j^
C -Fi^+j^
D Fi^+j^

The correct answer is:
-Fi^+j^

Solution:
τ → = r → × F →
Find the position vector with respect to O(origin) is r →
F⁡ → = - F k ^
r⁡→=-i⁡^+j⁡^
τ → = r⁡ → × F⁡ →
=-i⁡^+j⁡^×F⁡-k^
=-j⁡^+-i⁡^F⁡
=F⁡-i⁡^-j⁡^

Topic: Physics, Rotational Motion, NEET
A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant DNA by:

Options:
A EcoRI
B Taq polymerase
C DNA polymerase III
D DNA ligase

The correct answer is:
DNA ligase

Solution:
Ligase is a class of enzymes that catalyse the formation of covalent bonds using the energy released by the cleavage of ATP. Ligases are important in the synthesis and repair of many biological molecules, including DNA ligase and used in genetic engineering to insert foreign DNA into cloning vectors.

Topic: Biology, Biotechnology - Principles and Processes, NEET
A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using:

Options:
A EcoRI
B Taq polymerase
C Polymerase III
D DNA ligase

The correct answer is:
DNA ligase

Solution:
Ligase is a class of enzymes that catalyse the formation of covalent bonds using the energy released by the cleavage of ATP. Ligases are important in the synthesis and repair of many biological molecules, including DNA ligase and used in genetic engineering to insert foreign DNA into cloning vectors.

Topic: Biology, Biotechnology - Principles and Processes, NEET
A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using

Options:
A EcoRI
B Taq polymerase
C Polymerase III
D Ligase

The correct answer is:
Ligase

Solution:
In DNA recombinant technology, linking of foreign DNA and the plasmid is made possible by DNA ligase which is also called "molecular glue".

Topic: Biology, Biotechnology - Principles and Processes, NEET, NEET 2016 (Phase 2)
A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using

Options:
A EcoRI
B Taq polymerase
C Polymerase III
D Ligase

The correct answer is:
Ligase

Solution:
In DNA recombinant technology, linking of foreign DNA and the plasmid is made possible by DNA ligase which is also called "molecular glue".

Topic: Biology, Biotechnology - Principles and Processes, NEET
A foreign gene is inserted in pBR322 using the restriction endonuclease EcoRI. Which of these is true about the E. coli having this pBR322?

Options:
A It will be resistant to both antibiotic ampicillin as well as antibiotic tetracycline
B It will be resistant to antibiotic ampicillin but not resistant to antibiotic tetracycline
C It will be resistant to antibiotic tetracycline but not resistant to antibiotic ampicillin
D It will be neither be resistant to antibiotic tetracycline nor to antibiotic ampicillin

The correct answer is:
It will be resistant to both antibiotic ampicillin as well as antibiotic tetracycline

Solution:
The restriction site for EcoRI in pBR322 is not present within the ampicillin-resistant gene or within the tetracycline-resistant gene. Thus, when the foreign DNA is added, there will not be insertional activation of any of these genes and the bacterium will be resistant to both antibiotics.

Topic: Biology, Biotechnology - Principles and Processes, NEET
A form of genetic variation wherein different nucleotide sequences can be present at different sites in a molecule of DNA is called ____

Options:
A Transcription
B Polymorphism
C Translation
D Bioinformatics

The correct answer is:
Polymorphism

Solution:
A form of genetic variation wherein different nucleotide sequences can be present at different sites in a molecule of DNA is called polymorphism.

Topic: Biology, Molecular Basis of Inheritance, NEET
A forward biased diode is:

Options:
A

B

C

D

The correct answer is:

Solution:
A diode is bound to be forward biased if $p$-type semi conducts of $p-n$ function is at high potential w.r.t.ntype semi conductor of $p-n$ function. It is so for circuit (a).

Topic: Physics, Semiconductors, NEET, NEET 2006
A frame made of a metallic wire enclosing a surface area A is covered with a soap film. If the area of the frame of metallic wire is reduced by 50%, the energy of the soap film will be changed by

Options:
A 100%
B 75%
C 50%
D 25%

The correct answer is:
50%

Solution:
Surface energy = surface tension Ã surface area
E=SÃ2A
New surface energy,
% decrease in surface energy =E-E1EÃ100
=2 SA-SA2 SAÃ100=50%

Topic: Physics, Mechanical Properties of Fluids, NEET
A free-living, anaerobic, nitrogen-fixing bacterium is

Options:
A Rhizobium
B Streptococcus
C Azotobacter
D Clostridium

The correct answer is:
Clostridium

Solution:
Rhizobium can carry out nitrogen fixation only in a symbiotic state when it forms root nodules with leguminous plants. Azotobacter is a free-living aerobic nitrogen fixer and Clostridium is a free-living anaerobic nitrogen fixer. Streptococcus is saprophytic bacteria.

Topic: Biology, Mineral Nutrition, NEET
A free-living nitrogen-fixing cyanobacterium which can also form a symbiotic association with the water fern Azolla is

Options:
A Tolypothrix
B Chlorella
C Nostoc
D Anabaena

The correct answer is:
Anabaena

Solution:
The freshwater fern Azolla harbors Anabaena (a blue-green alga) in its leaf cavities. Chlorella is simply a green alga. Nostoc and Tolypothrix are a free-living cyanobacterium involved in N2 fixation.

Topic: Biology, Mineral Nutrition, NEET
A free-living soil bacterium capable of N2 fixation is

Options:
A Rhizobium
B Azotobacter
C Streptococcus
D Anabaena

The correct answer is:
Azotobacter

Solution:
Bacteria can fix atmospheric nitrogen while free-living in the soil (examples Azospirillum and Azotobacter). Thus, they enrich the nitrogen content of the soil.

Topic: Biology, Microbes in Human Welfare, NEET
A freshly prepared Fe(OH)3 precipitate is peptised by adding FeCl3 solution. The charge on the colloidal particles is due to the preferential adsorption of

Options:
A Cl- ions
B Fe3+ ions
C OH- ions
D Fe+2 ions

The correct answer is:
Fe3+ ions

Solution:
Fe(OH)3 is a positive sol. The positive charge is due to the preferential adsorption of Fe3+ ions

Topic: Chemistry, Surface Chemistry, NEET
A freshly prepared radioactive source of half-life 2 h emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is

Options:
A 6 h
B 12 h
C 24 h
D 128 h

The correct answer is:
12 h

Solution:
From R=R0 12 n
we have, 1=64(12)n
Or number of half lives =n=6
â´ t=nÃtt1/2=6Ã2=12 h

Topic: Physics, Nuclear Physics, NEET
A freshly prepared radioactive source of half-life 2 hours emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is

Options:
A 6 h
B 12 h
C 24 h
D 128 h

The correct answer is:
12 h

Solution:
NN0=12tt12
164=12tt12
tt12=6
Therefore t=6×t12

Topic: Physics, Nuclear Physics, NEET
A frog can be levitated in magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as

Options:
A paramagnetic
B diamagnetic
C ferromagnetic
D anti-ferromagnetic

The correct answer is:
diamagnetic

Solution:
Frog is levitated in the magnetic field produced by the current in vertical solenoid due to repulsion, so we can say the body of frog behaves as diamagnetic substance.

Topic: Physics, Magnetic Properties of Matter, NEET
A fruit developed from hypanthodium inflorescence is called

Options:
A hesperidium
B sorosis
C syconus
D caryopsis

The correct answer is:
syconus

Solution:
Syconus fruit develops from hypanthodium inflorescence, eg, Ficus carica, F. religiosa, $F$. benghalensis. The flask shaped receptacle encloses female flowers that gives rise to achene-like fruitlets. This fruit possesses a small pore protected by scaly leaves. The receptacle that becomes fleshy is edible.

Topic: Biology, Morphology of Flowering Plants, NEET, NEET 2009 (Screening)
A fruit which develops from a polycarpellary, apocarpous gynoecium of a single flower is called

Options:
A simple fruit
B composite fruit
C aggregate fruit
D multiple fruits

The correct answer is:
aggregate fruit

Solution:
Depending on the arrangement from where they develop, the fruit can be categorized as simple fruits, aggregate fruits, multiple fruits, and accessory fruits. When a fruit develops from a single ovary (monocarpellary) of a single flower it is known as a simple fruit, eg: plum and peaches, which may be fleshy, and walnuts which fall in the dry category. Aggregate fruits are the ones that are formed from several ovaries (polycarpellary) of a single flower, eg: strawberry. Composite or multiple fruits develop from different flowers of a whole inflorescence group together, eg: pineapple, figs etc.

Topic: Biology, Morphology of Flowering Plants, NEET
A fuel cell involves combustion of the butane at 1 atm and 298 K,
C4H10(g)+132O2(g)â4CO2(g)+5H2O(l)
ÎGÂ°=-2746 kJ/mol
What is EÂ° of a cell?

Options:
A +4.74 V
B +0.547 V
C +1.09 V
D +4.37 V

The correct answer is:
+1.09 V

Solution:
In the reaction
C4H10g-10+10+132O2gâ4CO2g+4-4+5H2Ol
Change in oxidation number of carbon =+16-(-10)=+26
So number of electrons involved in cell process will be 26.
EÂ°=-ÎGÂ°nF=(-2746)Ã100026Ã96500
=+1.09 V

Topic: Chemistry, Electrochemistry, NEET
A fuel cell involves combustion of the butane at at 1 atm and 298 K
C4H10(g)+132O2(g)→4CO2(g)+5H2O(l)
ΔG°=-2746 kJ/mole
The value of Ecello is nearly?

Options:
A 0.8 V
B 1 V
C 1.2 V
D 1.4 V

The correct answer is:
1 V

Solution:
C4-10H10(g)+132O2(g)→4CO2+4(g)+5H2O(l)
Here total change in oxidation number of C-atoms =+16-(-10)=+26
It means total number of e- involved = 26
As Ecello--ΔG°nF=-(-2746)×100026×96500
=+1.09V
≈1.0V

Topic: Chemistry, Electrochemistry, NEET
A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output?

Options:
A Load resistance
B A centre-tapped transformer
C p-n junction diodes
D Capacitor

The correct answer is:
Capacitor

Solution:
The design of full wave rectifier is as shown below.

The capacitor in the initial part is uncharged. That means no voltage difference exists between the plates of the capacitor. So when the voltage is turned on, the charging of the capacitor happens immediately.

During this conduction period, the capacitor charges to the maximum value of the input supply voltage. The capacitor stores a maximum charge exactly at the quarter positive half cycle in the waveform. At this point, the supply voltage is equal to the capacitor voltage.

When the AC voltage starts decreasing and becomes less than the capacitor voltage, then the capacitor starts slowly discharging. So the capacitor does not get enough time to completely discharged. Before the complete discharge of the capacitor happens, the charging again takes place. So only half or more than half of the capacitor charge get discharged.

The pulsating Direct Current (DC) produced by the full wave rectifier contains both AC and DC components. Capacitor allows the AC components and blocks the DC components of the current. So the capacitor component removes the ac ripple.

Topic: Physics, Semiconductors, NEET, NEET 2023 (All India)
A fully charged capacitor has a capacitance C. It is discharged through a small coil of resistance wire embedded in a thermally insulated block of specific heat capacity s and mass m. If the temperature of the block is raised by ∆T, the potential difference V across the capacitance is

Options:
A 2mCâTs
B mCâTs
C msâTC
D 2m sâTC

The correct answer is:
2m sâTC

Solution:
E=12CV2 ...(i)
The energy stored in capacitor is lost in form of heat energy
H=ms âT ...(ii)
From Eqs. (i) and (ii), we have
ms âT=12CV2
V= 2 msâTC

Topic: Physics, Electrostatics, NEET
A function is y=x3 . The approximate value of the function at x=2.0001 is possibly (choose the closest answer possible)

Options:
A 8.0006
B 8.0008
C 8.0012
D 8.0015

The correct answer is:
8.0012

Solution:
consider y=x3 at x=2
y+ây=2.00013=2+0.00013=x+âx3
and ây=3x2âx
â¹ây=322Ã0.0001=0.0012
â´y=23+â³y=8.0012

Topic: Physics, Units and Dimensions, NEET