datavorous/entrance-exam-dataset huggingface dataset:
A uniform spring has an unstretched length L and a force constant k. The spring is cut into two parts of unstretched lengths l1 and l2 such that l2=Î·l2, where Î· is an integer. The corresponding force constants are k1 and k2, then

Options:
A force has to be kept same to find k1 and k2
B k1=kη+1η and k2=kη-1
C k1=kη-1η and k2=kη+1
D k1=kÎ·+1Î· and k2=kÎ·+1

The correct answer is:
k1=kÎ·+1Î· and k2=kÎ·+1

Solution:
In case of cutting of a spring, lÃk=constant
k1l1=k2l2
k1Î·l2=k2l2 âÎ·k1=k2 ...............(1)
Now both the springs when connected in series should give the same effect as that of the original spring. Hence, by applying the concept of springs connected in series, we obtain,
1k=1k1+1k2 ...............(2)
1k=1k1+1Î·k1 âk1k=Î·+1Î· (using (1))
k1=Î·+1Î·k ............(3)
Using (3) again in (2), we obtain,
k2=Î·+1k

Topic: Physics, Oscillations, NEET
A uniform spring of normal length l has a force constant k. It is cut into two pieces of length l1 and l2 such that l1=nl2 where n is an integer. Then the value of k1 (force constant of spring of length l1) is-

Options:
A knn+1
B kn+1n
C kn-1n
D knn-1

The correct answer is:
kn+1n

Solution:
Using the relation kx = constant
k1l1=k2l2=k l1+l2
k1=kl1+l2l1 or k1=knl2+l2nl2
or k1=kn+1n

Topic: Physics, Oscillations, NEET
A uniform wire of diameter $d$ carries a current of 100 mA when the mean drift velocity of electrons in the wire is $v$. For a wire of diameter $\frac{d}{2}$ of the same material to carry a current of 200 mA , the mean drift velocity of electrons in the wire is

Options:
A $4 v$
B $8 v$
C $v$
D $2 v$

The correct answer is:
$8 v$

Solution:
current $i=n A v_d \mathrm{e}$
( $v_d=$ mean drift velocity $)$
$=n\left(\frac{\pi D^2}{4}\right) v_d e$
$\therefore i \propto D^2 v_d$
$\frac{100}{200}=\frac{(d)^2}{\left(\frac{d}{2}\right)^2} \times \frac{v}{v^{\prime}}$
$\Rightarrow v^{\prime}=2 \times 2^2 v=8 v$

Topic: Physics, Current Electricity, NEET, NEET 2024 (Re-NEET)
A uniform wooden plank of mass 150 kg and length 8 m is floating on still water with a man of 50 kg at one end of it. The man walks to the other end of the plank and stops. Then the distance covered by the plank is

Options:
A 1 m

B 4 m

C 2 m

D Zero

The correct answer is:
2 m

Solution:
Since there is no external force on the system m 1 Îâ x 1 = m 2 Îâ x 2
508-d=150Ãd
8-d=3d
âd=2 m

Topic: Physics, Center of Mass Momentum and Collision, NEET
A uniformly charged hemisphere of radius b and charge density ρ has a hemispherical cavity of radius aa=b2 cut from its centre. If the potential at the centre of the cavity is nρb216∈0 then n=?

Options:
A 3
B 4
C 5
D 6

The correct answer is:
3

Solution:
V=∫abK2πx2dxρx
V=2πkρb2-a22=πρkb2-a2
b=2a
v=3πkρb2

Topic: Physics, Electrostatics, NEET
A uniformly charged thin spherical shell of radius R carries a uniform surface charge density of σ per unit area. It is made of two hemispherical shells, held together by pressing them with force F (see figure). F is proportional to

Options:
A 1ε0σ2 R2
B 1ε0σ2 R
C 1ε0 σ2R
D 1ε0 σ2R2

The correct answer is:
1ε0σ2 R2

Solution:
Electrical force per unit area
=12ε0E2
=12ε0σε02=σ22ε0
Projected area =πR2
∴ Net electrical force
=σ22ε0πR2
In equilibrium, this force should be equal to the applied force.
∴ F=πσ2R22ε0
Or F∝σ2R2ε0

Topic: Physics, Electrostatics, NEET
A uniformly wound solenoid coil of self-inductance 1.8Ã10-4 H and resistance 6 Î© is broken up into two identical coils. These identical coils are then connected in parallel across a 12 V battery of negligible resistance. The time constant for the current in the circuit is

Options:
A 0.1×10-4 s
B 0.2Ã10-4 s
C 0.3Ã10-4 s
D 0.4Ã10-4 s

The correct answer is:
0.3Ã10-4 s

Solution:
Given, self-inductance, L=1.8Ã10-4 H
Resistance, R=6 Î©
When self-inductance and resistance are broken up into identical coils.
Then, the self-inductance of each oil
= 1.8Ã10-42 H
The resistance of each oil
= 6Î©2=3 Î©
Coil are then connected in parallel
( L eq = L 1 L 2 L 1 + L 2 )
â´ Lâ²=1.82Ã10-4Ã1.82Ã10-41.82Ã10-4+1.82Ã10-4
=0.45Ã10-4 H
and Râ²=3Ã33+3=1.5Î©
( R eq = R 1 R 2 R 1 + R 2 )
Time constant =Lâ²Râ²
= 0.45Ã10-41.5=0.3Ã10-4 s

Topic: Physics, Alternating Current, NEET
A unique vascular connection between the digestive tract and liver is called

Options:
A Hepato-pancreatic system
B Hepatic portal system
C Renal portal system
D Hepato-cystic system

The correct answer is:
Hepatic portal system

Solution:
Organ to organ transportation of any substance/nutrients is called portal system, occurs via special veins called Portal veins. Transfer of material from digestive tract to liver is via HepatoPortal veins.

Topic: Biology, Digestion and Absorption, NEET, NEET 2022 (Phase 2)
A unique vascular connection that exists between the digestive tract and liver is commonly known as

Options:
A Venous system
B Arterial system
C Lymphatic system
D Portal system

The correct answer is:
Portal system

Solution:
The hepatic portal system represents the vascular connection between the digestive tract and liver. The hepatic portal vein carries nutrient-rich blood from the intestine to the liver before it is delivered to the systemic circulation.

Topic: Biology, Digestion and Absorption, NEET
A unit composed of a sugar and base linked by the Î²-glycosidic bond is known as a

Options:
A Nucleotide
B Nucleoside
C Glycoside
D Purine

The correct answer is:
Nucleoside

Solution:
A nucleoside is made up of sugar and a nitrogenous base.

Topic: Chemistry, Biomolecules, NEET
A unit of area, often used in measuring land areas, is the hectare defined as 104 m2. An open-pit coal mine consumes 75 hectares of land, down to a depth of 26 m, each year. What volume of earth, in a cubic kilometre, is removed in this time?

Options:
A 0.01
B 0.02
C 0.03
D 0.04

The correct answer is:
0.02

Solution:
Required volume =75×104×26103×103×103 km3 =0.02 km3

Topic: Physics, Units and Dimensions, NEET
A U-tube of base length L filled with the same volume of two liquids of densities ρ and 2ρ is moving with acceleration a on the horizontal plane. If the height difference between the two surfaces (open to atmosphere) becomes zero, then the height h is given by

Options:
A aL2g
B 3aL2g
C aLg
D 2aL3g

The correct answer is:
3aL2g

Solution:
The pressure at the left bottom due to left vertical pipe =PL=Patm+h2Ïg
The pressure at the right bottom due to right vertical pipe =PR=Patm+hÏg
and Pressure difference in the horizontal tube due to acceleration
PLR=L2Ïa+L22Ïa
PLR=3LÏa2
The pressure at the left bottom due to right vertical pipe and horizontal pipe
PL=PR+PLR
PL=Patm+hÏg+3LÏa2
The pressure at the left bottom due to left vertical pipe=Pressure at the left bottom due to right vertical pipe and horizontal pipe
Patm+h2Ïg=Patm+hÏg+3LÏa2
âh=3aL2g

Topic: Physics, Mechanical Properties of Fluids, NEET
A variable force F acts along the x-axis given by F=3x2-2x+1 N. The work done by the force when a particle of mass 100 g moves from x=50 cm to x=100 cm is

Options:
A 0.625 J
B 6.25 J
C 0.0625 J
D 62.5 J

The correct answer is:
0.625 J

Solution:
xinitial=50 cm
xfinal=100 cm
Therefore work done by the variable force,
W=â«xinitialxfinalF.dx
W=â«0.513x2-2x+1dx
W=x3-x2+x0.51
W=1-0.53-1-0.52+1-0.5
W=0.875-0.75+0.5
W=0.625 J

Topic: Physics, Work Power Energy, NEET
A variety effective against shoot and fruit borer is

Options:
A Pusa Gaurav
B Pusa Sawani
C Pusa Sem 2
D Pusa Sem 3

The correct answer is:
Pusa Sawani

Solution:
Crop	Variety	Insect Pests

Brassica	Pusa Gaurav	Aphids

Flat bean	Pusa Sem 2, Pusa Sem 3	Jassids, aphids, and fruit borer

Okra	Pusa Sawani, Pusa A-4	Shoot and fruit borer

Topic: Biology, Strategies for Enhancement in Food Production, NEET
A. Variety of Brassica.
B. Have resistance to white rust disease.
C. Developed by hybridisation and selection.

The above statements are true for:

Options:
A Pusa gaurav
B Pusa sadabahar
C Pusa swarnim
D Pusa sawani

The correct answer is:
Pusa swarnim

Solution:
Pusa swarnim is the disease-resistant variety of Brassica. It is resistant against white rust and developed through hybridization and selection.

Topic: Biology, Strategies for Enhancement in Food Production, NEET
A vegetative propagules in aquatic plants like Eichhornia (water hyacinth) is called

Options:
A Stolon
B Offset
C Prop root
D Bulb

The correct answer is:
Offset

Solution:
An offset develops from below a tuft or rosette of leaves, grows for sometimes, and bears a new tuft or rosette of leaves at its tip. e.g. Eichhornia.

Topic: Biology, Morphology of Flowering Plants, NEET
A vehicle of mass m is moving on a rough horizontal road with momentum p. If the coefficient of friction between the tyres and the road is μ, then the stopping distance is

Options:
A p2μmg
B p22μmg
C p2μm2g
D p22μm2g

The correct answer is:
p22μm2g

Solution:
From work energy theorems,
p 2 2m =μmgs  ⇒  S=p22μm2g

Topic: Physics, Work Power Energy, NEET
A vein possesses a large lumen because

Options:
A Tunica media and tunica externa form a single coat
B Tunica interna and tunica media form a single coat
C Tunica interna, tunica media and tunica externa are thin
D Tunica media is a thin coat

The correct answer is:
Tunica media is a thin coat

Solution:
Basically each artery and vein consists of three layers: an inner lining of squamous endothelium (the tunica interna), a middle layer of smooth muscle and elastic fibre (the tunica media), and an external layer of fibrous connective tissue with collagen fibres (the tunica externa).

Topic: Biology, Body Fluids and Circulation, NEET
A vein possesses a large lumen because

Options:
A

Tunica media and tunica externa form a single coat

B

Tunica interna and tunica media form a single coat

C

Tunica interna, tunica media and tunica externa are thin

D

Tunica media is a thin coat

The correct answer is:

Tunica media is a thin coat

Solution:
The wall of blood vessels is made up of tunica externa, tunica media, and tunica interna. Veins have a larger lumen when compared to the arteries. The middle layer i.e., tunica media is a dense network of circular, smooth muscles with elastic fibres found in arteries. It is comparatively very thin in veins.

Topic: Biology, Body Fluids and Circulation, NEET
A vertical capillary of radius r is brought in contact with water of density ρ and surface tension S. If the angle of contact is zero, then the amount of heat liberated while the water rises along the capillary, is

Options:
A 2 Ï Sâ¡ 2 Ï gâ¡
B π S&ApplyFunction; 2 ρ g&ApplyFunction;
C Zero
D 4 π S&ApplyFunction; 2 ρ g&ApplyFunction;

The correct answer is:
2 π S⁡ 2 ρ g⁡

Solution:
W⁡ST=πr⁡2h⁡ρg⁡h⁡,W⁡g⁡=πr⁡2h⁡ρg⁡h⁡2
Heat=Q=W⁡ST-W⁡g⁡=πr⁡2ρg⁡h⁡22andh⁡=2S⁡r⁡ρg⁡
⇒Q⁡=2πS⁡2ρg⁡

Topic: Physics, Mechanical Properties of Fluids, NEET
A vertical column of a certain liquid, 50 cm long at 50 oC balances another column of the same liquid, 60 cm long at 100 oC. The coefficient of absolute expansion of the liquid is

Options:
A 0.005 /oC
B 0.0005 /oC
C 0.002 /oC
D 0.0002 /oC

The correct answer is:
0.005 /oC

Solution:
h1gÏ1=h2gÏ2
h1h2=Ï2Ï1=1+Î³ Î¸11+Î³ Î¸2 âµ Ï=Ï01+Î³ Î¸
â5060=1+Î³Ã501+Î³Ã100
âÎ³=0.005 /oC

Topic: Physics, Thermal Properties of Matter, NEET
A vertical spring of force constant 100 N m-1 is attached with a hanging mass of 10 kg. Now an external force is applied on the mass so that the spring is stretched by an additional 2 m. The work done by the external force is : ( g=10 m s-2 )

Options:
A 200 J
B 400Â J
C 450Â J
D 600Â J

The correct answer is:
200 J

Solution:
At equilibrium, mg=kx0 âx0=mgk=1 m
â´W=U2 â U1
=12 kx22â 12 kx12+mgh
=12 k x22 â x12 â mgh
=12 Ã 100 Ã 32 â 12 â 10 Ã 10 Ã 2=200 J

Topic: Physics, Work Power Energy, NEET
A vertical spring with force constant $k$ is fixed on a table. A ball of mass $m$ at a height $h$ above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance $d$. The net work done in the process is

Options:
A $m g(h+d)-\frac{1}{2} k d^2$
B $m g(h-d)-\frac{1}{2} k d^2$
C $m g(h-d)+\frac{1}{2} k d^2$
D $m g(h+d)+\frac{1}{2} k d^2$

The correct answer is:
$m g(h+d)-\frac{1}{2} k d^2$

Solution:
Net work done = work done by gravitational force + work done by spring force
$=m g(h+d)-\frac{1}{2} k d^2$

Topic: Physics, Work Power Energy, NEET, NEET 2007
A vertical tube of length 100 cm contains a mercury pallet of length 5 cm as shown in the figure. The length of the tube above mercury pallet if the tube is inverted is nearly: (atmospheric pressure = 75 cm Hgof Hg)

Options:
A 56 cm

B 57 cm

C 60 cm

D 50 cm

The correct answer is:
57 cm

Solution:
P1Ã50=P2Ãx
âx=50P1P2
P1=80 cm of Hg
P2=70 cm of Hg
â´x=50Ã8070
=57.12 cmâ57 cm

Topic: Physics, Kinetic Theory of Gases, NEET
A very broad elevator is going up vertically with a constant acceleration of 2ms-2. At the instant when its velocity is 4 ms-1 a ball is projected from the floor of the elevator with a speed of 4 ms-1 with respect to the elevator at an angle of 30Â°. The time taken by the ball to return the floor is (g=10 ms-2)

Options:
A 1/2 s
B 1/3 s
C 1/4 s
D 1 s

The correct answer is:
1/3 s

Solution:
Components of velocity of ball relative to lift are
ux=4cos30Â°=23ms-1
and uy=4sin30Â°=2ms-1
and acceleration of ball relative to lift is 12 ms-2 in negative y-direction or vertically downwards. Hence, time of flight
T=2uy12=uy6=26=13s

Topic: Physics, Motion In Two Dimensions, NEET
A very broad elevator is going vertically upwards with a constant acceleration of 2 ms-2. At the instant when its velocity is 4 ms-1, a ball is projected from the floor of the lift with a speed of 4 ms-1 relative to the floor at an angle of 30Â°. The time of flight of the ball in the elevator is (g=10 ms-2)

Options:
A 12 sâ¡
B 13 sâ¡
C 14 sâ¡
D 1 s

The correct answer is:
13 sâ¡

Solution:
Components of velocity of ball relative to lift are :
ux = 4 cos 30o = 2 3 m/s
and uy=4 sin 30Â°=2 m/s
and acceleration of ball relative to lift is 12ââm/s2 in negative y-direction or vertically downwards. Hence time of flight
Tâ¡=2uâ¡y12=uâ¡y6=26=13 sâ¡

Topic: Physics, Motion In Two Dimensions, NEET
A very long conducting wire is bent in a semi- circular shape from A to B as shown in figure. The magnetic field at point P for steady current configuration is given by:

Options:
A μ0i4R1-2π pointed into the page
B μ0i4R pointed into the page
C μ0i4R pointed away from the page
D μ0i4R1-2π pointed away from the page

The correct answer is:
μ0i4R1-2π pointed away from the page

Solution:
Let's consider the following diagram:

The formula to calculate the magnetic field B→1 due to wire 1 is given by

B→1=μ0i4πR⊗ ...1

The formula to calculate the magnetic field B→2 due to wire 2 is given by

B→2=μ0i4R⊙ ...2

And, the formula to calculate the magnetic field B→3 due to wire 3 is given by

B→3=μ0i4πR⊗ ...3

Hence, the net magnetic field at P can be written as

B→=B→1+B→2+B→3= μ0i4πR⊗ +μ0i4R⊙ + μ0i4πR⊗ =μ0i2πR⊗+μ0i4R⊙= -μ0i2πR⊙+μ0i4R⊙=μ0i4R1-2π⊙

Topic: Physics, Magnetic Effects of Current, NEET, NEET 2023 (All India)
A very long metallic hollow pipe of length l and radius r (<<l) is carrying charge Q, uniformly distributed upon it. The pipe is rotated about its axis with constant angular speed Ï. The energy stored in the pipe of length l100 is

Options:
A μ0Q2ω2r2100πl
B μ0Q2ω2r2200πl
C μ0Q2ω2r2800πl
D μ0Q2ω2r2400πl

The correct answer is:
μ0Q2ω2r2800πl

Solution:
I=QT=Qω2π⇒I'=Il=Qω2πl
B=μ0I'=μ0Qω2πl⇒U=B22μ0×Volume
U=12μ0×μ02Q2ω24π2l2×πr2l100=μ0Q2ω2r2800πl

Topic: Physics, Magnetic Effects of Current, NEET
A very long straight wire carries a current I. At the instant when a charge $+Q$ at point $\mathrm{P}$ has velocity $\bar{v}$ as shown the force on the charge is:

Options:
A along y
B opposite $y$
C along $x$
D Opposite $x$

The correct answer is:
along y

Solution:
According to Fleming's left hand rule direction of force is along $y$ axis when is perpendicular to wire:
$$
\vec{F}=Q(\vec{V} \times \vec{B})
$$
$\mathrm{B}$ due to $\mathrm{I}$ is acting inwards is into the paper, $v$ is along or:
$$
\begin{array}{ll}
\therefore & F=a+\left|\begin{array}{ccc}
\hat{i} & \hat{h} & \hat{k} \\
v & 0 & 0 \\
0 & 0 & -\mathrm{B}
\end{array}\right| \\
\Rightarrow & F=Q+[-j(-v B)+0] \\
\therefore & F=Q v B \hat{j}
\end{array}
$$
in $y$ direction.

Topic: Physics, Magnetic Effects of Current, NEET, NEET 2005
A very long uniformly charged rod falls with a constant velocity V through the centre of a circular loop. Then the magnitude of induced emf in the loop is

Options:
A μ02πλV2
B μ02λV2
C μ02λV
D zero

The correct answer is:
zero

Solution:
As charged rod is moving with constant velocity
∴ Magnetic field due to its motion is also constant, no change in flux so no emf.

Topic: Physics, Electromagnetic Induction, NEET
A very narrow capillary tube records a rise of 20 cm when dipped in water. When the area of cross-section is reduced to one-fourth of former value, water will rise to a height of

Options:
A 10Â cm
B 20Â cm
C 40 cm
D 80Â cm

The correct answer is:
40 cm

Solution:
A∝r2
∴ radius becomes half.
As Hr constant
∴H becomes double.

Topic: Physics, Mechanical Properties of Fluids, NEET
A very small hole in an electric furnace is used for heating metals. The hole nearly acts as a black body. The area of the hole is 200 mm2. To keep a metal at 727 Â°C, heat energy flowing through this hole per sec, in joules, is ( take Ï=5.67Ã10-8 W m-2 K-4 )

Options:
A 22.68
B 2.268
C 1.134
D 11.34

The correct answer is:
11.34

Solution:
By Stefan's law,
if the absolute temperature of a black body is T, then the energy E emitted per second per unit surface area of the body
EâT4
E =Ï AT4
Given,
Ï=5.67Ã10-8 W m-2 K-4
T=727+273=1000 K
A=200Ã10-6 m
E=5.67Ã10-8Ã200Ã10-6Ã10004
=5.67Ã2Ã10-12Ã1012
=11.34 J s-1

Topic: Physics, Thermal Properties of Matter, NEET
A vessel completely filled with water has holes A and B at depths h and 3h from the top respectively. The hole A is a square of side L and B is a circle of radius r. The water flowing out per second from both the holes is same. Then L is equal to

Options:
A r12π12312
B rπ14314
C rπ12314
D r12π13312

The correct answer is:
rπ12314

Solution:
A 1 V 1 = A 1 V 2
L 2 2 gh = π r 2 6 gh
L 4 gh = π 2 r 4 3 gh
L = π 1 2 r 3 1 4
L = r π 1 2 3 1 4

Topic: Physics, Mechanical Properties of Fluids, NEET
A vessel contains 1 mole of O2 gas (molar mass 32) at a temperature T. The pressure of the gas is p. An identical vessel containing one mole of the gas (molar mass 4) at a temperature 2T has a pressure of

Options:
A p8
B p
C 2p
D 8p

The correct answer is:
2p

Solution:
pV=nRT

or p=nRTV

or pâT

V and n are same for both gases. Therefore, if T is doubled, pressure also becomes two times i.e. 2p

Topic: Physics, Thermodynamics, NEET
A vessel contains $3.2 \mathrm{~g}$ of dioxygen gas at STP (273.15 $\mathrm{K}$ and 1 atm pressure). The gas is now transferred to another vessel at constant temperature, where pressure becomes one third of the original pressure. The volume of new vessel in $\mathrm{L}$ is :
(Given - molar volume at STP is $22.4 \mathrm{~L}$ )

Options:
A 6.72
B 2.24
C 22.4
D 67.2

The correct answer is:
6.72

Solution:
No. of moles of $\mathrm{O}_2=\frac{\text { Given weight of } \mathrm{O}_2}{\text { Mol. weight of } \mathrm{O}_2}$
$=\frac{3.2}{32}=0.1$
Molar vol. at $\mathrm{STP}=0.1 \times 22.4=2.24 \mathrm{~L}$
$\mathrm{P}_1=1 \mathrm{~atm}, \mathrm{~V}_1=2.24 \mathrm{~L}, \mathrm{P}_2=\frac{1}{3} \mathrm{~atm}, \mathrm{~V}_2=$ ?
According to Boyle's law : $\mathrm{P}_1 \mathrm{~V}_1=\mathrm{P}_2 \mathrm{~V}_2$
$\begin{aligned}
\therefore 1 \times 2.24 & =\frac{1}{3} \times \mathrm{V}_2 \\
\mathrm{~V}_2 & =2.24 \times 3 \\
& =6.72 \mathrm{~L}
\end{aligned}$

Topic: Chemistry, States of Matter, NEET, NEET 2022 (Phase 2)
A vessel contains a mixture of one mole of oxygen and two moles of nitrogen at 300 K. The ratio of the average rotational kinetic energy per O2 molecule to per N2 molecule is

Options:
A 1:1
B 1:2
C 2:1
D depends on the moment of inertia of the two molecules

The correct answer is:
1:1

Solution:
Average kinetic energy per molecule per degree of freedom =12kT. Since, both the gases are diatomic and at the same temperature 300 K, both will have the same number of rotational degree of freedom i.e., two. Therefore, both the gases will have the same average rotational kinetic energy per molecule =2Ã12kT=kT. Thus, ratio will be 1:1.

Topic: Physics, Thermodynamics, NEET
A vessel contains oil (density 0.9 g cc-1) over mercury (density 13.6 g cc-1). A homogeneous sphere floats with one-third of its volume immersed in mercury and the rest immersed in oil. The density of the material of the sphere in g cc-1 is

Options:
A 3.3
B 6.4
C 5.1
D 12.8

The correct answer is:
5.1

Solution:
For equilibrium, the total upward push will be equal to the downward pull. If V is the volume of the sphere, then we have
V⁡313.6g+2V⁡30.9g=V⁡ρg
∴ρ=13.6+1.82g cm-3=5.1g cm-3

Topic: Physics, Mechanical Properties of Fluids, NEET
A vessel of 120 mL capacity contains a certain amount of gas at 35 °C and 1.2 bar pressure. The gas is transferred to another vessel of volume 180 mL at 35 °C. What would be its pressure?

Options:
A 1.3 bar
B 0.8 bar
C 0.4 bar
D 1.6 bar

The correct answer is:
0.8 bar

Solution:
Correct Option is : (B)
0.8 bar

Topic: Chemistry, States of Matter, NEET
A vessel of depth 2h is half filled with a liquid of refractive index 22 and the upper half with another liquid of refractive index 2 . The liquids are immiscible. The apparent depth of the inner surface of the bottom of the vessel will be

Options:
A h2
B h22+1
C h32
D 32h4

The correct answer is:
32h4

Solution:
d=h2+h22

⇒d=h2×32=32h4

Topic: Physics, Ray Optics, NEET
A vessel of volume 20 L contains a mixture of hydrogen and helium at a temperature of 27 Â°C and pressure 2.0 atm. The mass of the mixture is 5 g. Assuming the gases to be ideal, the ratio of the mass of hydrogen to that of helium in the given mixture will be

Options:
A 1 : 2
B 2 : 3
C 2 : 1
D 2 : 5

The correct answer is:
2 : 5

Solution:
Suppose there are n1 moles of hydrogen and n2 moles of helium in the given mixture. Then the pressure of the mixture will be

ââââP=n1RTV+n2RTV=n1+n2RTV
2×101.3×103=n1+n28.330020×10-3
n1+n2=2×101.3×103×20×10-38.3300=1.62 ...(i)
The mass of the mixture is (in g)
n 1 × 2 + n 2 × 4 = 5
n 1 + 2 n 2 = 2.5 ......(ii)
Solving Eqs. (i) and (ii), n1 = 0.74, n2 = 0.88
Hence mHmHe=0.74×20.88×4=1.483.52→2 : 5

Topic: Physics, Thermodynamics, NEET
A vessel of volume 5000 cm3 contains 120 moles of molecular nitrogen at 1800 K. If 30% of the molecules are now dissociated the pressure inside the vessel (in Pa) will be

Options:
A 1.49×105
B 1.94×105
C 2.25×105
D 3.78×105

The correct answer is:
1.94×105

Solution:
As 30% of the molecules are now dissociated then new number of moles are
n=1201.3
And hence the new pressure is
PV=nRT
P5000Ã10-6=1201.38.3141800
P=1.94Ã105 Pa

Topic: Physics, Thermodynamics, NEET
A vibration magnetometer placed in magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2 sec in earth's horizontal magnetic field of 24 microtesla. When horizontal field 18 microtesla is produced opposite to the earth's field by placing a current carrying wire, the new time period of the magnet will be

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

The correct answer is:
4 s

Solution:
Time period of a vibration magnetometer,
T â1B
â T1T2= B2B1
â T2=T1B1B2
=2 24 Ã10-66 Ã10-6=4 s

Topic: Physics, Magnetic Properties of Matter, NEET
A virus which has RNA as genetic material is:

Options:
A Cauliflower mosaic virus
B Smallpox
C Tobacco mosaic virus
D Herpes virus

The correct answer is:
Tobacco mosaic virus

Solution:
Tobacco mosaic virus has rna as genetic material.

Topic: Biology, Molecular Basis of Inheritance, NEET