datavorous/entrance-exam-dataset huggingface dataset:
Three concentric spherical shells have radii $a, b$ and $c(a < b < c)$ and have surface charge densities $\sigma,-\sigma$ and $\sigma$ respectively. If $V_A, V_B$ and $V_C$ denote the potentials of the three shells, then for $c=a+b$, we have

Options:
A $\mathrm{V}_{\mathrm{C}}=\mathrm{V}_{\mathrm{A}} \neq \mathrm{V}_{\mathrm{B}}$
B $\mathrm{V}_{\mathrm{C}}=\mathrm{V}_{\mathrm{B}} \neq \mathrm{V}_{\mathrm{A}}$
C $\mathrm{V}_{\mathrm{C}} \neq \mathrm{V}_{\mathrm{B}} \neq \mathrm{V}_{\mathrm{A}}$
D $\mathrm{V}_{\mathrm{C}}=\mathrm{V}_{\mathrm{B}}=\mathrm{V}_{\mathrm{A}}$

The correct answer is:
$\mathrm{V}_{\mathrm{C}}=\mathrm{V}_{\mathrm{A}} \neq \mathrm{V}_{\mathrm{B}}$

Solution:
Here,
$$
\begin{aligned}
& \mathrm{V}_{\mathrm{A}}=\frac{1}{4 \pi \varepsilon_0} \frac{\sigma 4 \pi \mathrm{a}^2}{\mathrm{a}}-\frac{1}{4 \pi \varepsilon_0} \frac{\sigma 4 \pi \mathrm{b}^2}{\mathrm{~b}} \\
& +\frac{1}{4 \pi \varepsilon_0} \cdot \frac{\sigma 4 \pi c^2}{c} \\
& =\frac{\sigma}{\varepsilon_0}(a-b+c)=\frac{\sigma}{\varepsilon_0}(2 a) \quad(\because c=a+b) \\
&
\end{aligned}
$$
$$
\begin{aligned}
& \mathrm{V}_{\mathrm{B}}=\frac{1}{4 \pi \varepsilon_0} \cdot \frac{\sigma 4 \pi \mathrm{a}^2}{\mathrm{a}}-\frac{1}{4 \pi \varepsilon_0} \frac{\sigma 4 \pi \mathrm{b}^2}{\mathrm{~b}} \\
&+\frac{1}{4 \pi \varepsilon_0} \cdot \frac{\sigma 4 \pi \mathrm{c}^2}{\mathrm{c}}
\end{aligned}
$$
$$
\begin{aligned}
& =\frac{\sigma}{\varepsilon_0}\left(\frac{a^2}{c}-b+c\right)=\frac{\sigma}{\varepsilon_0}(2 a)(\because c=a+b) \\
& \text { and } V_C=\frac{1}{4 \pi \varepsilon_0} \cdot \frac{\sigma 4 \pi a^2}{c}-\frac{1}{4 \pi \varepsilon_0} \frac{\sigma 4 \pi b^2}{c} \\
& +\frac{1}{4 \pi \varepsilon_0} \cdot \frac{\sigma 4 \pi c^2}{c} \\
& =\frac{\sigma}{\varepsilon_0}\left(\frac{a^2}{c}-\frac{b^2}{c}+c\right)=\frac{\sigma}{\varepsilon_0}(2 a)(\because c=a+b) \\
&
\end{aligned}
$$
Hence, $\mathrm{V}_{\mathrm{A}}=\mathrm{V}_{\mathrm{C}} \neq \mathrm{V}_{\mathrm{B}}$

Topic: Physics, Electrostatics, NEET, NEET 2009 (Screening)
Three cylindrical rods A, B and C of equal lengths and equal diameters are joined in series as shown in the diagram. Their thermal conductivities are 2K, K and 0.5 K respectively. In steady-state, if the free ends of rods A and C are at 100 Â°C and 0 Â°C respectively. Assume negligible loss through the curved surface. What will be the equivalent thermal conductivity?

Options:
A Keq=67K
B Keq=45K
C Keq=87K
D Keq=76K

The correct answer is:
Keq=67K

Solution:
As the rods are in series, Req = RA + RB + RC with R = (LKA)
i.e.,Req=L2KA+LKA+L0.5KA=7L2KA....(i)
Furthermore if Keq is equivalent thermal conductivity,
Req=L+L+LKeqA=7L2KAfrom Equation (i)
i.e., ⇒ 3LKeq=7L2KA
⇒Keq=67K

Topic: Physics, Thermal Properties of Matter, NEET
Three discs A, B and C having radii 2 m, 4 m and 6 m respectively are coated with carbon black on their outer surfaces. The wavelength corresponding to maximum intensities are 300 nm, 400 nm and 500 nm respectively. The power radiated by them are Q A ,ââ Q B and Q C respectively. Then,

Options:
A Q A is maximum
B Q B is maximum
C Q C is maximum
D Q A =   Q B = Q C

The correct answer is:
Q B is maximum

Solution:
The radiant power i.e., energy radiated by a body per unit time is given by
Q t = A Îµ Ï T 4
â Q â AT 4
also, Î» m T = constant
â Q â A Î» m 4
Power radiated, Q â AT 4 and Î» m T = constant
Hence, Q â A Î» m 4 or Q â r 2 Î» m 4
Q A : Q B : Q C = 2 2 3 4 : 4 2 4 4 : 6 2 5 4 = 0.05 : 0.0625 : 0.0576
i.e, Q B is maximum.

Topic: Physics, Thermal Properties of Matter, NEET
Three electrolytic cells A, B, C containing solutions of ZnSO₄, AgNO₃ and CuSO₄, respectively are connected in series. A steady current of 1.5 amperes was passed through them until 1.45 g of silver deposited at the cathode of cell B. How long did the current flow? What mass of copper and zinc were deposited?

Options:
A 15 min, 0.734 g Cu, 0.426 g Zn
B 14 min, 1.42 g Cu, 0.43 g Zn
C 45 min, 0.426 g Cu, 0.734 g Zn
D 60 min, 0.426 g Cu, 0.734 g Zn

The correct answer is:
14 min, 1.42 g Cu, 0.43 g Zn

Solution:
Correct Option is : (B)
14 min, 1.42 g Cu, 0.43 g Zn

Topic: Chemistry, Electrochemistry, NEET
Three equal masses m are rigidly connected to each other by massless rods of length l forming an equilateral triangle, as shown above. The assembly is to be given an angular velocity Ï about an axis perpendicular to the triangle. For fixed Ï , what is the ratio of the kinetic energy of the assembly for an axis through B to an axis through A?

Options:
A 1:2

B 2:1
C 3:2
D 1:3

The correct answer is:
2:1

Solution:
IA=ml32×3=ml2
IB=ml2+ml2⇒IB=2mll2
KEB=12IBω2⇒KEB=122ml2ω2
KEA=12IAω2⇒KEA=12ml2ω2
KEBKEA=122ml2ω212ml2ω2=21

Topic: Physics, Rotational Motion, NEET
Three Faraday of electricity is passed through aqueous solutions of AgNO3,NiSO4 and CoCl3 kept in three vessels using inert electrodes. The ratio in mol in which the metals Ag, Ni and Co will be deposited is

Options:
A 3:2:1
B 1:2:3
C 2:3:6
D 6:3:2

The correct answer is:
6:3:2

Solution:
(i)  Ag + (aq) + e − 1 mol = 1 F      3 F → Ag (s) 1 mol 3 mol
(ii)  Ni 2+ (aq)  +  2e − 2 mol = 2 F       3 F → Ni (s)   1 mol 3/2 mol
(iii)  Co + (aq) +  3e − 3 mol = 3 F → Co (s) 1 mol
The required ratio of moles of Ag, Ni and Co is
3 mol Ag: 3/2 mol Ni : 1 mol Co or 6 mol Ag : 3 mol Ni : 2 mol Co.

Topic: Chemistry, Electrochemistry, NEET
Three floral diagrams are given here. Their respective families are assigned in the answer key. Find out the families to which these diagrams belong to

Options:
A A - Liliaceae, B - Asteraceae, C - Solanaceae
B A - Asteraceae, B - Solanaceae, C - Brassicaceae
C A - Asteraceae, B - Solanaceae, C - Asteraceae
D A - Poaceae, B - Solanaceae, C - Asteraceae

The correct answer is:
A - Asteraceae, B - Solanaceae, C - Brassicaceae

Solution:
'Pappus', a hairy structure is a modification of calyx and is the characteristic feature of a family - Asteraceae.
So, is the floral formula of a family - Asteraceae.
Calyx 5, gamosepalous, persistent, corolla 5, gamopetalous. Androecium 5, polyandrous and gynoecium bicarpellary and syncarpous are the diagnostic feature of a family - Solanaceae, shown by floral formula
Calyx 4, polysepalous and arranged in 2 worlds of 2 each, corolla 4, polypetalous and cruciform. Androecium 6, polyandrous, tetradynamous.
Gynoecouim, bicarpellary, syncarpous and superior, placentation pariential with a partition called replum.
These are the diagnostic feature of a family - Brassicaceae or Cruciferae, shown by floral formula

Topic: Biology, Morphology of Flowering Plants, NEET
Three forces acting on a body are shown in the figure. To have the resultant force only along the $y$-direction, the magnitude of the minimum additional force needed is

Options:
A $0.5 \mathrm{~N}$
B $1.5 \mathrm{~N}$
C $\frac{\sqrt{3}}{4} \mathrm{~N}$
D $\sqrt{3} \mathrm{~N}$

The correct answer is:
$0.5 \mathrm{~N}$

Solution:
Minimum additional force needed
$\begin{aligned}
& F=-\left(F_{\text {resultant }}\right)_x \\
& F_{\text {resultant }}=[(4-2)(\cos 30 \hat{\mathbf{j}}-\sin 30 \hat{\mathbf{i}}) \\
= & {\left[2\left(\frac{\sqrt{3}}{2} \hat{\mathbf{j}}-\frac{1}{2} \hat{\mathbf{i}}\right)+\left(\frac{1}{2} \hat{\mathbf{i}}+\frac{\sqrt{3}}{2} \hat{\mathbf{j}}\right)\right] } \\
= & {\left[\left(\sqrt{3}+\frac{\sqrt{3}}{2}\right) \hat{\mathbf{j}}+\sin 60 \hat{\mathbf{j}}\right) } \\
= & {\left.\left[-\frac{1}{2} \hat{\mathbf{i}}+\frac{3 \sqrt{3}}{2} \hat{\mathbf{i}}+\frac{\hat{\mathbf{i}}}{2}\right)\right] } \\
= & -\frac{\hat{\mathbf{i}}}{2}+\frac{3 \sqrt{3}}{2} \hat{\mathbf{j}} \quad F=-\left(-\frac{\hat{\mathbf{i}}}{2}\right)=\frac{1}{2} \hat{\mathbf{i}}\end{aligned}$
Hence,
$|F|=0.5 \mathrm{~N}$

Topic: Physics, Mathematics in Physics, NEET, NEET 2008 (Screening)
Three identical blocks A,B and C are placed on horizontal frictionless surface. The blocks B and C are at rest. But A is approaching towards B with a speed 10 m s-1 . The coefficient of restitution for all collisions is 0.5. The speed of the block C just after the collision is

Options:
A 5.6 m s-1
B 6 m s-1
C 8 m s-1
D 10 m s-1

The correct answer is:
5.6 m s-1

Solution:
Initially B is at rest.
After collision vB=m1(1+e)m1+m2u1
vB=m(1+0.5)m+m10
vB=7.5 m s-1
Initially C is at rest, and moving B collides with C ,then
vC=m2(1+e)m2+m3u2
vC=m(1+0.5)m+m7.5
vC=5.6 m s-1

Topic: Physics, Center of Mass Momentum and Collision, NEET
Three identical blocks each of mass M are along a frictionless table and a force F is acting as shown. Which of the following statement is false?

Options:
A The net vertical force on block A is zero
B The net force on block A is F3
C The acceleration of block C is F3M
D The force of interaction between A and B is F3

The correct answer is:
The force of interaction between A and B is F3

Solution:
The acceleration of the system in rightward direction is
a=FmA+mB+mC=F3M
For A
From force diagram of A, the Net force on A =F-F1
=m1a=MF3M=F3
The force interaction between A and B is F1=F-F3=2F3

Topic: Physics, Laws of Motion, NEET
Three identical charges are placed on three vertices of a square. If the force acting between q1 and q2 is F12 and between q1 and q3 is F13 then F13F12= ________.

Options:
A 12
B 2
C 12
D 2

The correct answer is:
12

Solution:
F12=Kq2a2
F13=Kq22a2=Kq22a2
F13F12=12

Topic: Physics, Electrostatics, NEET
Three identical metal plates of area â²Aâ² are at distance d1 & d2 from each other. Metal plate A is uncharged, while plate B & C have respective charges +q & -q. If metal plates A & C are connected by switch K through a consumer of unknown resistance, what energy does the consumer give out to its surrounding?
Assume d1=d2=d

Options:
A q2d4ε0A
B q2dε0A
C q2d2ε0A
D 2q2dε0A

The correct answer is:
q2d4ε0A

Solution:
We know that
Energy loss = 12C2C+CÃV2 = 12C2Ãq2C2
= q24C = q2d4Îµ0A

Topic: Physics, Electrostatics, NEET
Three identical rods each of mass M and length

Options:
A 23 Ml2
B Ml24
C Ml22
D none

The correct answer is:
Ml22

Solution:
I=I1+I2+I3
=Mlsin⁡60°23+Mlsin⁡60°23+0=Ml22

Topic: Physics, Rotational Motion, NEET
Three identical rods each of mass M , length l are joined to form an equilateral ÎABC . Find the Moment of Inertia about BC as shown.

Options:
A 23Ml2
B Ml24
C Ml22
D none

The correct answer is:
Ml22

Solution:
I=I1+I2+I3=M(lsin60°)23+M(lsin60°)23+0=Ml22

Topic: Physics, Rotational Motion, NEET
Three identical spheres, each of mass M, are placed at the corners of a right angle triangle with mutually perpendicular sides equal to 2 m (see figure). Taking the point of intersection of the two mutually perpendicular sides as the origin, find the position vector of centre of mass.

Options:
A 2i^+j^
B i^+j^
C 23i^+j^
D 43i^+j^

The correct answer is:
23i^+j^

Solution:
First, recall the formula of the center of mass of n particle system,

rcm=m1r1+m2r2+m3r3+...+mnrnm1+m2+m3+..+mn

⇒xcom=M×0+M×2+M×03M=23

⇒ycom =M×0+M+2+M×03M=23

So the position vector of center of mass is, 23i^+23j^.

Topic: Physics, Center of Mass Momentum and Collision, NEET, NEET 2020 (Phase 2)
Three identical spheres lie at rest along a line on a smooth horizontal surface. The separation between any two adjacent spheres is L. The first sphere is moving with a velocity u towards the second sphere at time t=0. The coefficient of restitution for a collision between any two blocks is 13. The correct statement is

Options:
A The third sphere will start moving at t=5L2u
B The third sphere will start moving at t=4Lu
C The centre of mass of the system will have a final speed 2u
D The centre of mass of the system will have a final speed u

The correct answer is:
The third sphere will start moving at t=5L2u

Solution:
First sphere will take a time t1, to start motion in second sphere on colliding with it, where t1=Lu
Now speed of second sphere will be
v2=u21+e=23u
Hence, time taken by second sphere to start motion in third sphere
∴ Total time t=t1+t2=Lu+3L2u=5L2u

Topic: Physics, Center of Mass Momentum and Collision, NEET
Three identical spheres of mass M each are placed at the corners of an equilateral triangle of side 2 m. Taking one of the corners as the origin as shown in the figure, the position vector of the centre of mass is

Options:
A 3 i^-j^
B i ^ 3 + j ^
C i^+j^3
D i ^ + j ^ 3

The correct answer is:
i ^ + j ^ 3

Solution:
The x coordinate of centre of mass is
x com = ∑ M i x i ∑ M i
= M×0+M×1+M×2 M+M+M =1
y com = ∑ m i y i ∑ m i
= M×0+M×( 2 sin 60 )+M×0 M+M+M
y com = 3 M 3M = 1 3
Position vector of centre of mass is i^+j^3.

Topic: Physics, Center of Mass Momentum and Collision, NEET
Three identical spheres of mass M each are placed at the corners of an equilateral triangle of side 2 m. Taking one of the corners as the origin as shown in the figure, the position vector of the centre of mass is

Options:
A 3 (i^-j^)
B i ^ 3 + j ^
C i^+j^3
D i ^ + j ^ 3

The correct answer is:
i ^ + j ^ 3

Solution:
The x coordinate of centre of mass is
x com = ∑ M i x i ∑ M i
= M×0+M×1+M×2 M+M+M =1
y com = ∑ m i y i ∑ m i
= M×0+M×( 2 sin 60 )+M×0 M+M+M
y com = 3 M 3M = 1 3
Position vector of centre of mass is i^+j^3.

Topic: Physics, Center of Mass Momentum and Collision, NEET
Three identical spherical shells, each of mass m and radius r are placed as shown in the figure. Consider an axis XX′ which is touching the two shells and passing through the diameter of the third shell. The moment of inertia of the system consisting of these three spherical shells about XX′ axis is:

Options:
A 115 mr2
B 3mr2
C 165mr2
D 4mr2

The correct answer is:
4mr2

Solution:
âââââââ

Total moment of inertia of the system,
I+I1+I2+I3
I2=I3=23mr2+mr2=5mr23
I1=23mr2
∴I=2×5mr23+23mr2
I=12mr23=4mr2

Topic: Physics, Rotational Motion, NEET, NEET 2015 (Phase 1)
Three identical spherical shells, each of mass m and radius r are placed as shown in the figure. Consider an axis XXâ² which is touching the two shells and passing through diameter of the third shell. Moment of inertia of the system consisting of these three spherical shells about XXâ² axis is:

Options:
A 115 mr2
B 3 mr2
C 165mr2
D 4 mr2

The correct answer is:
4 mr2

Solution:
Total MI of the system,
I=I1+I2+I3
I2=I3=23mr2+mr2=5mr23
I1=23mr2
â´I=2Ã5mr23+23mr2
=12mr23=4 mr2

Topic: Physics, Rotational Motion, NEET
Three ions H+, He+ and O+2 having the same kinetic energy pass through a region in which there is a uniform magnetic field perpendicular to their velocity, then

Options:
A H + will be least deflected.
B H e + and O + 2 will be deflected equally.
C O + 2 will be deflected most.
D All will be deflected equally.

The correct answer is:
H e + and O + 2 will be deflected equally.

Solution:
r=2mEqB⇒r∝mq⇒rH+ : rHe+ : rO+2=11:41:162=1:2:2

Topic: Physics, Magnetic Effects of Current, NEET
Three levels of biodiversity are

Options:
A Genetic diversity, species diversity and ecological diversity
B Species diversity, ecological diversity and habitat diversity
C Geographical diversity, genetic diversity and habitat diversity
D Ecological diversity, species diversity and community diversity

The correct answer is:
Genetic diversity, species diversity and ecological diversity

Solution:
Immense diversity (heterogeneity) exists in our biosphere, not only at the species level but at all the levels of biological organisation ranging from the macromolecules within cells to biomes.
Sociobiologist Edward Wilson described the combined diversity at all the levels of biological organisation. These are genetic diversity, species diversity and ecological diversity.

Topic: Biology, Biodiversity and its Conservation, NEET
Three lines are drawn from a single corner of an
FCC unit cell to meet the other corner such that they are found to pass through exactly-1-Octahedral void only, no voids Octahedral void only. Identify the line in the same order –

Options:
A Edge, Face diagonal, Body diagonal
B Face diagonal, Edge Body diagonal
C Body diagonal, Face diagonal Edge
D Edge, Body diagonal, Face diagonal

The correct answer is:
Edge, Face diagonal, Body diagonal

Solution:
Edge has one octahedral void; face has no void while body diagonal contain one octahedral and two tetrahedral voids.

Topic: Chemistry, Solid State, NEET
Three liquids of densities, ρ1, ρ2 and ρ3 (with, ρ1>ρ2>ρ3), having the same value of surface tension,T , rise to the same height in three identical capillaries. The angles of contact, θ1, θ2 and θ3 obey

Options:
A π2>θ1>θ2>θ3≥0
B 0≤θ1<θ2<θ3<π2
C π2<θ1<θ2<θ3<π
D π>θ1>θ2>θ3>π2

The correct answer is:
0≤θ1<θ2<θ3<π2

Solution:
h=2Tcosθrρg.

⇒ρ∝cosθ (as T, hand r are constants).

Therefore, ρ↑⇒θ↓.

θ1<θ2<θ3

The liquid is rising, so, 0≤θ1<θ2<θ3<π2.

Topic: Physics, Mechanical Properties of Fluids, NEET, NEET 2016 (Phase 2)
Three long straight conductors are arranged parallel to each other in the same plane. They carry currents of 1 A, 2 A and 3 A in the same direction. The distance between the first two conductors is x and the distance between the second and third conductors is y. If the middle conductor is in equilibrium, then the ratio x:y is

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

The correct answer is:
1:3

Solution:
Force per unit length between two current carrying parallel wire is given by :
F=μ0i1i22πr &
f12+f23=0
μ o 1×2 2π x = μ o 2×3 2πy x y = 1 3

Topic: Physics, Magnetic Effects of Current, NEET
Three masses 2 kg, 3 kg and 4 kg are lying at the corners of an equilateral triangle of side l . The X coordinate of center of mass is

Options:
A 712l
B 59l
C 729l
D 59l

The correct answer is:
59l

Solution:
The X coordinate of center of mass is,
Xcm=m1x1+m2x2+m3x3m1+m2+m3
Xcm=20+3l+4l22+3+4
Xcm=59l

Topic: Physics, Rotational Motion, NEET
Three masses are connected as shown in figure on a horizontal frictionless surface and pulled by a force of 60 N. The tensions T1 and T2 are in the ratio

Options:
A 1 : 1
B 1 : 5
C 1 : 4
D 4 : 5

The correct answer is:
1 : 5

Solution:
For the total system, T1 and T2 becomes internal force.
â a = F ext m and calculate T1 and T2.
âa
3kgâT1
âa
3+12kgâT2
T1T2=3A15A=15

Topic: Physics, Laws of Motion, NEET
Three mile Island and Chernobyl incident are related to

Options:
A soil pollution
B water pollution
C air pollution
D radioactive pollution

The correct answer is:
radioactive pollution

Solution:
Initially nuclear energy was hailed as a nonpolluting way for generating electricity, but it has two serious inherent problems. First is the accidental leakage, as occurred in the Three Miles island and Chernobyl incident and the second is the safe disposal of radioactive waste.

Topic: Biology, Environmental Issues, NEET
Three Mile Island in Dauphin county, Pennsylvania, USA is known for

Options:
A Its ground-breaking solid waste management technology
B Its meltdown of nuclear reactor causing massive radiation leakage
C Its initiative to control greenhouse emission and CFCs
D Its massive afforestation to preserve biodiversity

The correct answer is:
Its meltdown of nuclear reactor causing massive radiation leakage

Solution:
On March 28, 1979, there was a partial meltdown of the Three Mile Island nuclear reactor number 2. Due to this many radioactive gases and radioactive iodine were released in the environment.

Topic: Biology, Environmental Issues, NEET
Three moles of B2H6 are completely reacted with methanol. The number of moles of boron containing product formed is

Options:
A 2
B 4
C 6
D 3

The correct answer is:
6

Solution:
B2H6+6MeOH→2B(OMe)3+6H2
Diborane reacts with methanol to give hydrogen and trimethoxyborate ester.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Three non-conducting large parallel plates have surface charge densities σ,-2σ and 4σ respectively as shown in the figure. The electric field at the point P is

Options:
A σε0
B σ2ε0
C 3σ2ε0
D 3σε0

The correct answer is:
3σ2ε0

Solution:
The electric charge densities are Ï, -2Ï and 4Ï respectively.
Hence, electric field at point P is given by
EP=Ï2Îµ0+-2Ï2Îµ0+4Ï2Îµ0
=Ï-2Ï+4Ï2Îµ0
=3Ï2Îµ0

Topic: Physics, Electrostatics, NEET
Three objects, A : (a solid sphere), B : (a thin circular disk) and C : (a circular ring), each have the same mass M and radius R . They all spin with the same angular speed ω about their own symmetric axes. The amounts of work (W) required to bring them to rest, would satisfy the relation

Options:
A WB>WA>WC
B WA>WB>WC
C WC>WB>WA
D WA>WC>WB

The correct answer is:
WC>WB>WA

Solution:
By work-energy theorem
W=loss in KE=12IÏ2
IA=25MR2=0.4MR2
IB=12 MR2=0.5 MR2
IC=MR2
â´ WC>WB>WA

Topic: Physics, Rotational Motion, NEET, NEET 2018
Three of the following pairs of the human skeletal parts are correctly matched with their respective inclusive skeletal category and one pair is not matched. Identify the non-matching pair.

Options:
A

Pairs of skeletal parts	Category

(a)	Sternum and Ribs	Axial skeleton

B

Pairs of skeletal parts	Category

(b)	Clavicle and Glenoid cavity	Pelvic girdle

C

Pairs of skeletal parts	Category

(c)	Humerus and Ulna	Appendicular skeleton

D

Pairs of skeletal parts	Category

(d)	Malleus and Stapes	Ear ossicles

The correct answer is:

Pairs of skeletal parts	Category

(b)	Clavicle and Glenoid cavity	Pelvic girdle

Solution:
The glenoid cavity is found in the pectoral girdle.

The glenoid cavity or glenoid fossa of the scapula is a part of the shoulder. It is a shallow, pyriform articular surface, which is located on the lateral angle of the scapula. It is directed laterally and forward and articulates with the head of the humerus; it is broader below than above and its vertical diameter is the longest.

Topic: Biology, Locomotion and Movement, NEET
Three of the following statements about enzymes are correct and one is wrong. The wrong option is

Options:
A Higher temperature destroys enzymatic activity because proteins are denatured by heat.
B Enzymes are denatured at high temperature but in certain exceptional organisms they are
effective even at temperatures from 80°–90°C.
C Enzymes lower the activation energy and hasten the enzyme-catalyzed reaction.
D Most of the enzymes are active intracellular only and gets inactivated under extracellular conditions

The correct answer is:
Most of the enzymes are active intracellular only and gets inactivated under extracellular conditions

Solution:
All enzymes are proteins. There is some nucleic acid (rRNA) that functions as enzymes, these are called ribozymes. Enzymes get denatured at high temperatures, except enzymes isolated from the thermophilic organisms. Enzymes are highly specific as only a specific group of the substrate can bind to the active site of the enzyme. Enzymes are active both in intracellular and extracellular conditions.

Topic: Chemistry, Biomolecules, NEET
Three Î±-particles combine to form a 12C nucleus, the mass defect is
(atomic mass of 2He4 is 4.002603 u)

Options:
A 0.007809 u

B 0.002603 u

C 4.002603 u

D 0.5 u

The correct answer is:
0.007809 u

Solution:
Mass defect
âm=Total mass of Î±-particles-mass of 12C nucleus
=3Ã 4.002603-12
=12.007809-12
=0.007809 u

Topic: Physics, Nuclear Physics, NEET
Three pairs of compounds are given below. Identify that compound in each of the pairs which has group 13 element in more stable oxidation state

Options:
A TlCl3
B AlCl3
C InCl3
D All have same stability

The correct answer is:
TlCl3

Solution:
Correct Option is : (A)
TlCl3

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Three particles, each of mass $m$ gram, are situated at the vertices of an equilateral triangle $\mathrm{ABC}$ side $l \mathrm{~cm}$ (as shown in the figure). The moment of inertia of the system about a line $\mathrm{AX}$ perpendicular to $A B$ and in the plane of $A B C$, in gram $\mathrm{cm}^2$ units will be:

Options:
A $\frac{3}{4} m l^2$
B $2 \mathrm{ml}$
C $\frac{5}{4} m l^2$
D $\frac{3}{2} m l^2$

The correct answer is:
$\frac{5}{4} m l^2$

Solution:
According to the question
$$
\begin{aligned}
I_{A X} & =m l^2+m\left(\frac{l}{2}\right)^2 \\
& =m l^2+\frac{5}{4} \\
& =\frac{5}{4} m l^2
\end{aligned}
$$

Topic: Physics, Rotational Motion, NEET, NEET 2004