datavorous/entrance-exam-dataset huggingface dataset:
Two trains are moving in the same direction along parallel tracks. One of them is 200 m long travelling with a velocity of 20 m s-1. The second one is 800 m long travelling with a velocity of 7.5 m s-1. The time taken for the first train to overtake the second is

Options:
A 20 s
B 40 s
C 60 s
D 80 s

The correct answer is:
80 s

Solution:
From the figure, the relative displacement is
srel=800+200m=1000 m
Ïrel=Ï1-Ï2=20-7.5 m s-1
=12.5 m s-1
â´t=srelÏrel=100012.5=80 s

Topic: Physics, Motion In Two Dimensions, NEET
Two traits, that is starch synthesis and shape of seed in Pea is

Options:
A Two effects of same gene
B Two different effects of two different gene
C case of epistasis
D Two different effects of group of genes

The correct answer is:
Two effects of same gene

Solution:
Gene is a segment of DNA responsible for expression of proteins which in true expresses the character or feature represented by the gene. When this gene is regulating the expression of more than one feature in an organism such phenomenon is called pleiotropy.
In pea plant, starch synthesis is controlled by a single gene with two alleles B and b. The homozygous form BB produces large size starch grain and bb produces smaller size starch grain. Also, it was observed that this gene was controlling the shape of seed as well. On maturity, BB condition produced round shape seed and bb produced wrinkled seed. Single gene was effectively regulating the multiple phenotypic expression - seed shape and starch synthesis.

Topic: Biology, Principles of Inheritance and Variation, NEET
Two tubes A and B are in series. The radius of A is R and that of B is 2R. If water flows through A with velocity v then the velocity of water through B is

Options:
A v2
B v
C v4
D v8

The correct answer is:
v4

Solution:
Form principle of continuity
A1v1=A2v2
ÏR2⋅v=Ï2R2⋅v2
v2=v4

Topic: Physics, Mechanical Properties of Fluids, NEET
Two tuning forks A and B are sounded together and it results in beats with frequency of 4 beats per second. When A is loaded with wax, they again produces 4 beats per second. If frequency of A is 256 Hz, then the frequency of B is

Options:
A 252 Hz
B 262 Hz
C A and B both
D None

The correct answer is:
252 Hz

Solution:
Since A produces four beats with B.
So, frequency of B could be 260 Hz or 252 Hz.
After waxing, frequency decreases. So, frequency of B has to be less than 256 Hz as it produces same number of beats with A.

So, the frequency of B is 252 Hz..

Topic: Physics, Waves and Sound, NEET
Two uniform thin rods each of mass M and length l are placed along X and Y axis with one end of each at the origin. Moment of inertia of the system about Z-axis is

Options:
A 32 Ml2
B 23 Ml2
C 2Ml2
D None of these

The correct answer is:
23 Ml2

Solution:
According to theorem of parallel axes, moment of inertia of a rod about one if its ends
=Ml212+Ml24=Ml23
∴ Moment of inertia of two rods about Z-axis=Moment of inertia of 2 rods placed along X and Y-axis =2Ml23

Topic: Physics, Rotational Motion, NEET
Two uniformly long charged wires with linear densities λ and 3λ are placed along X and Y axis respectively. Determined the slope of electric field at any point on the line y=3 x .

Options:
A 33
B 332
C 133
D 3

The correct answer is:
133

Solution:
Ex=3λ2πϵox
Ey=λ2πϵox3
E→=3λ2πε0x  i^+λ2πε0x3  j^
Slope=EyEx=13×3=133

Topic: Physics, Electrostatics, NEET
Two unknown resistances are connected in two gaps of a meter-bridge. The null point is obtained at 40 cm from left end. A 30 Î© resistance is connected in series with the smaller of the two resistances, the null point shifts by 20 cm to the right end. The value of smaller resistance in Î© is

Options:
A 12
B 24
C 36
D 48

The correct answer is:
24

Solution:
lx=40 cm, lR=60 cm
xR=lxlR=4060=23 ....... (i)
∴ x+30 R=6040=32
∴ x+30R=32
∴ 2x+30=3R
R= 2(x+30)3 ........ (ii)
From (i) and (ii),
3x2(x+30)=23
9x=4x+120
5x=120 ⇒ x=24 Ω

Topic: Physics, Current Electricity, NEET
Two very long, straight, parallel conductors A and $\mathrm{B}$ carry current of $5 \mathrm{~A}$ and $10 \mathrm{~A}$ respectively and are at a distance of $10 \mathrm{~cm}$ from each other. The direction of current in two conductors is same. The force acting per unit length between two conductors is $\left(\mu_0=4 \pi \times 10^{-7}\right.$ SI unit):

Options:
A $2 \times 10^{-4} \mathrm{Nm}^{-1}$ and is attractive
B $2 \times 10^{-4} \mathrm{Nm}^{-1}$ and is repulsive
C $1 \times 10^{-4} \mathrm{Nm}^{-1}$ and is attractive
D $1 \times 10^{-4} \mathrm{Nm}^{-1}$ and is repulsive

The correct answer is:
$1 \times 10^{-4} \mathrm{Nm}^{-1}$ and is attractive

Solution:
As per question,
$\begin{aligned}
\frac{\mathrm{F}}{l} & =\frac{\mu_{\mathrm{o}}}{4 \pi} \times \frac{2 \mathrm{I}_1 \mathrm{I}_2}{r} \\
& =\frac{4 \pi \times 10^{-7} \times 2 \times 5 \times 10}{2 \pi \times 0.1} \\
& =10^{-4} \mathrm{Nm}^{-1}
\end{aligned}$
The nature of the force is attractive.
(where, the symbols have their usual meanings)

Topic: Physics, Magnetic Effects of Current, NEET, NEET 2022 (Phase 2)
Two vessels 1 and 2, made out of different materials are Identical in all the geometrical aspects. In both the vessels, the same quantity of ice gets melted in 20 min and 30 min respectively. The ratio of the thermal conductivity of the second one to that of the first, is

Options:
A 1.5
B 1
C 23
D 4

The correct answer is:
1.5

Solution:
Heat transferred in time t is given by,
Q=KAθ1-θ2tl
in both the cases, A, l and θ1-θ2 are same so
Kt= constant
⇒ K2K1=t1t2
⇒ K2K1=3020=1.5

Topic: Physics, Thermal Properties of Matter, NEET
Two vessels separately contain two ideal gases A and B at the same temperature, the pressure of A being twice that of B. Under such conditions, the density of A is found to be 1.5 times the density of B. The ratio of molecular weights of A and B is

Options:
A 34
B 2
C 12
D 23

The correct answer is:
34

Solution:
PA= ρARTMA, PB= ρBRTMB

⇒ PAPB= ρAρB MBMA=2

⇒32MBMA=2
So, MAMB =34

Topic: Physics, Thermodynamics, NEET
Two vessels separately contain two ideal gases A and B at the same temperature, the pressure of A being twice that of B. Under such conditions, the density of A is found to be 1.5 times the density of B. The ratio of molecular weights of A and B is

Options:
A 34
B 2
C 12
D 23

The correct answer is:
34

Solution:
PA= ρARTMA, PB= ρBRTMB

⇒ PAPB= ρAρB MBMA

⇒32MBMA=2
So, MAMB =34

Topic: Physics, Kinetic Theory of Gases, NEET, NEET 2015 (Phase 2)
Two vibrating tuning forks produce progressive waves given $Y_1=4 \sin 500$ $\pi \mathrm{t}$ and $Y_2=2 \sin 506 \pi \mathrm{t}$. Number of beats produced per minute is:

Options:
A 360
B 180
C 60
D 3

The correct answer is:
180

Solution:
$\begin{aligned}
& y_1=4 \sin 500 \pi t \\
& y_2=2 \sin 506 \pi t \\
& \omega_1=500 \pi \text {, } \\
& \omega_2=500 \pi, \omega=2 \pi \\
& v_1=250, v_2=253 \\
&
\end{aligned}$
$\begin{aligned} \therefore \quad v & =v_2-v_1=253-250 \\ & =3 \mathrm{beats} / \mathrm{s}\end{aligned}$

Topic: Physics, Waves and Sound, NEET, NEET 2005
Two waves are represented by the equations $y_1=a \sin (\omega t+k x+0.57) \mathrm{m}$ and $y_2=a \cos (\omega t+k x) \mathrm{m}$, where $x$ is in metre and $t$ in second. The phase difference between them is

Options:
A $1.25 \mathrm{rad}$
B $1.57 \mathrm{rad}$
C $0.57 \mathrm{rad}$
D $1.0 \mathrm{rad}$

The correct answer is:
$1.0 \mathrm{rad}$

Solution:
$y_1=a \sin (\omega t+k x+0.57) \mathrm{m}$ and $y_2=a \cos (\omega t+k x) \mathrm{m}$ or $y_2=a \sin \left(\frac{\pi}{2}+\omega t+k x\right) \mathrm{m}$
Phase difference
$$
\begin{aligned}
& \Delta \phi=\phi_2-\phi_1 \\
& =\frac{\pi}{2}-0.57=1.57-0.57 \\
& =1 \mathrm{rad}
\end{aligned}
$$

Topic: Physics, Oscillations, NEET, NEET 2011 (Screening)
Two waves of the same frequency and same amplitude, on superimposition, produced a resultant disturbance of the same amplitude. The waves differ in phase by

Options:
A π
B 2π3
C π2
D zero

The correct answer is:
2π3

Solution:
Amplitude of resultant wave is
A2=A12+A22+2A1A2cos⁡θ
Given, A=A1=A2=a (let)
a2=a2+a2+2a2cos⁡θ
cos⁡θ=-12
θ=2π3

Topic: Physics, Waves and Sound, NEET
Two waves of wavelength 1.00 m and 1.01 m produces 10 beats in 3 s. What is the velocity of the wave?

Options:
A 150 m s-1
B 115.2 m s-1
C 336.6 m s-1
D 200 m s-1

The correct answer is:
336.6 m s-1

Solution:
v1=vÎ»1=v1.00 and v2=vÎ»2=v1.01
â´âv=v1-v2=v11.00-01.01=10
or v=10Ã1Ã1.010.01=1010 for 3s
â´v=336.6 m s-1

Topic: Physics, Waves and Sound, NEET
Two waves of wavelength 1.00 m and 1.01 m produces 10 beats in 3 s. What is the velocity of the wave?

Options:
A 150 m s-1
B 115.2 m s-1
C 336.6 m s-1
D 200 m s-1

The correct answer is:
336.6 m s-1

Solution:
ν1=vλ1=v1.00 and ν2=vλ2=v1.01
∴∆ν=ν1-ν2=v11.00-01.01=10
or v=10×1×1.010.01=1010 for 3 s
∴ v=336.6 m s-1

Topic: Physics, Waves and Sound, NEET
Two waves represented by the following equations are travelling in the same medium

y1=5sin⁡2π75t-0.25x

y2=10sin⁡2π150t-0.50x

The intensity ratio I1I2 of the two waves is

Options:
A 1:2
B 1:4
C 1:8
D 1:16

The correct answer is:
1:16

Solution:
I=12ρω2A2v
I1I2=ω12A12ω22A22
I1I2=7515025102
I1I2=116

Topic: Physics, Waves and Sound, NEET
Two waves represented by y=a sin (Ït - kx) and y=a cos (Ït-kx) are superposed. The resultant wave will have an amplitude

Options:
A a

B 2a
C 2a

D Zero

The correct answer is:
2a

Solution:
Given that, two waves
y=asin⁡ωt-ka
And y=a cos (ωt-kx)
Here, the phase difference between the two waves is π2.
So, the resultant amplitude
A=a12+a22+2a1a2cos⁡Φ
Here a1=a,a2=a,Φ=π2
∴A=a2+a2+2a acos⁡π2
or A=a2+a2+0
⟹A=2a

Topic: Physics, Waves and Sound, NEET
Two waves y1=3 sinâ¡Ït cm and y2=4 cos Ït+Ï2 cm produce the interference pattern. Then the amplitude of the resultant wave will be

Options:
A 1 cm
B 3 cm
C 4 cm
D 5 cm

The correct answer is:
5 cm

Solution:
A=a2+b2+2abcos⁡ϕ
=9+16+2 . abcos⁡π2=25=5

Topic: Physics, Wave Optics, NEET
Two weights w1 and w2 are suspended from the ends of a light string passing over a smooth fixed pulley. If the pulley is pulled up with acceleration g, the tension in the string will be

Options:
A 4w1 w2w1+ w2
B 2w1Â w2w1+Â w2
C w1-Â Â w2w1+Â w2
D w1Â w22w1-w2

The correct answer is:
4w1 w2w1+ w2

Solution:
For solving the problem, we assume that observer is situated in the frame of pulley (non - inertial reference frame).
m1g=w1
m2g=w2
From force diagram [a],
T-m2a0-w2=m2a
Or T-m2g-w2=m2a âµ a0=g
Or T-2w2=m2a .....(i)
From force diagram [b],
m1a0+w1-T=m1a
Or m1gâ¡+w1-T=m1a âµ a0=g
Or 2W1-T=m1a ......(ii)
From equations (i) and (ii),
T=4w1 w2w1+w2

Topic: Physics, Laws of Motion, NEET
Two wheels A and B are mounted on the same axle. Moment of inertia of A is 6 kg m2 and it is rotating at 600 rpm when B is at rest. What is the moment of inertia of B, if their combined speed is 400 rpm?

Options:
A 8 kg m2
B 4 kg m2
C 3 kg m2
D 5 kg m2

The correct answer is:
3 kg m2

Solution:
Applying the principle of conservation of angular momentum,
I1+I2ω=I1ω1+I2ω2
6+I240060×2π=6×60060×2π+I2×0
Which gives, I2=3 kg m2

Topic: Physics, Rotational Motion, NEET
Two white points are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm. Approximately, what is the maximum distance at which these dots can be resolved by the eye?
[Take wavelength of light = 500 nm]

Options:
A 5 m
B 1 m
C 6 m
D 3 m

The correct answer is:
5 m

Solution:
We know,
yDâ¥1.22Î»d
âDâ¤yd1.22Î»
=10-3Ã3Ã10-31.22Ã5Ã10-7
=306.1=5 m
â´ Dmaxâ¡ =5 m

Topic: Physics, Ray Optics, NEET
Two wires A and B are of the same materials. Their lengths are in the ratio 1 :2 and diameters are in the ratio 2 :1 . When stretched by force FA and FB respectively, they get an equal increase in their lengths. Then the ratio FAFB should be

Options:
A 1Â :2
B 1Â :1
C 2Â :1
D 8 :1

The correct answer is:
8 :1

Solution:
Force F=YAâll
Substituting area A=πd22=πd24
So, we have F=Yπd2âl4l
F∝d2âll âµYπ4=constant
Hence, using equation (i), we have
FA∝dA2âlAlA ...(i)
FB∝dB2âlBlB ...(ii)
Form equations (i) and (ii), we get
∴FAFB=dA2âlAlA×lBdB2âlB
As âlA= âlB=âl
Therefore FAFB= dA2dB2×lBlA
Putting dAdB=21
And lBlA=21
We get FA :FB=8 :1

Topic: Physics, Mechanical Properties of Solids, NEET
Two wires A and B of the same material, have radii in the ratio 1:2 and carry currents in the ratio 4:1. The ratio of drift speed of electrons in A and B is

Options:
A 16:1
B 1:16
C 1:4
D 4:1

The correct answer is:
16:1

Solution:
Drift speed of electrons is given by
I=neAvd
Therefore vd∝Ir2
(vd)A(vd)B=IAIB×rB2rA2
(vd)A(vd)B=41×2212=161

Topic: Physics, Current Electricity, NEET
Two wires are made of the same material and have the same volume. The first wire has cross-sectional area A and the second wire has cross-sectional area 3A. If the length of the first wire is increased by ∆l on applying a force F, how much force is needed to stretch the second wire by the same amount?

Options:
A 4F
B 6F
C 9F
D F

The correct answer is:
9F

Solution:
Y=FlA∆l
∵ V=Al so l=VA
F=YA∆ll=YA2∆lV
F1F2=A1A22⇒FF2=A3A2=19
F 2 =9 F 1 =9F

Topic: Physics, Mechanical Properties of Solids, NEET, NEET 2018
Two wires having the same length and material are stretched by the same force. Their diameters are in the ratio 1:3. The ratio of strain energy per unit volume for these two wires (smaller to larger diameter), when stretched, is

Options:
A 3:1

B 9:1
C 27:1
D 81:1

The correct answer is:
81:1

Solution:
Strain energy per unit volume u=UV=12×stress×strain
UV=12×FA×∆ll
U V = 1 2 Stress× Stress Y
∴  u S u L = Y L Y S × ( Strain( S ) Stress( S ) ) 2 = ( A L A S ) 2
= ( r L 2 r S 2 ) 2 =( 81 1 )

Topic: Physics, Mechanical Properties of Solids, NEET
Two wires of diameter 0.25 cm, one made of steel and the other made of brass are loaded as shown in Fig.. The unloaded length of steel wire is 1.5 m and that of brass wire is 1.0 m. What are elongations of the steel and the brass wires respectively.

Options:
A 1.49 mm, 1.3mm
B 1.49 mm, 0.13mm
C 0.149 mm, 1.3mm
D 0.149 mm, 0.13mm

The correct answer is:
0.149 mm, 0.13mm

Solution:
Correct Option is : (D)
0.149 mm, 0.13mm

Topic: Chemistry, Mechanical Properties of Solids, NEET
Two wires of equal diameters, of resistivities ρ1 and ρ2 and length l1 and l2, respectively are joined in series. The equivalent resistivity of the combination is

Options:
A ρ1l1+ρ2l2l1+l2
B ρ1l2+ρ2l1l1-l2
C ρ1l2+ρ2l1l1+l2
D ρ1l1+ρ2l2l1-l2

The correct answer is:
ρ1l1+ρ2l2l1+l2

Solution:
Wires having frame diameter, hence area of cross-section will be equal,
i.e. A1=A2=A
R1=ρ1.l1A
and R2=ρ2.l2A
Since, both resistance are joined in series.
Hence, Req=R1+R2
=ρ1.l1A+ρ2.l2A
Req=1Aρ1l1+ρ2l2
ρeq.l1+l2A=1Aρ1l1+ρ2l2
⇒ρeq=ρ1l1+ρ2l2l1+l2

Topic: Physics, Current Electricity, NEET
Two wires of the same material and lengths but having diameters in the ratio of 1:2 are stretched by a force of equal magnitude. The ratio of potential energy stored per unit volume for the two wires when stretched will be

Options:
A 16:1
B 2:1
C 4:1
D 1:1

The correct answer is:
16:1

Solution:
u=12 stress × strain
Stress =fA1; Strain =fA1Y
u∝1A2
u1u2=A22A12=4πr2πr22
u1u2=161

Topic: Physics, Mechanical Properties of Solids, NEET
Two wires that are made up of two different materials whose specific resistances are in the ratio 2:3, length 3:4 and area 4:5. The ratio of their resistance is-

Options:
A 6:5
B 6:8
C 5:8
D 1:2

The correct answer is:
5:8

Solution:
Use R=ρ lA
∴ R1R2=ρ1l1A1ρ2l2A2
5:8

Topic: Physics, Current Electricity, NEET
Type of flower and pollination that is observed in the given plant is

Options:
A Flower 1 is chasmogamous and undergoes self-pollination;
Flower 2 is cleistogamous and undergoes cross-pollination
B Flower 1 is cleistogamous and undergoes cross-pollination;
Flower 2 is chasmogamous and undergoes self-pollination
C Flower 1 is chasmogamous and undergoes self-pollination;
Flower 2 is chasmogamous and undergoes cross-pollination
D Flower 1 is chasmogamous and undergoes cross-pollination;
Flower 2 is cleistogamous and undergoes self-pollination

The correct answer is:
Flower 1 is chasmogamous and undergoes cross-pollination;
Flower 2 is cleistogamous and undergoes self-pollination

Solution:
Cleistogamous flowers never open and in them only self-pollination is operated. In Commelina benghalensis (kankauoa), the underground flowers are cleistogamous, in which Cleistogamy (a type of self-pollination) occurs. Most of the flowers are chasmogamous and undergoes cross-pollination.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
Type of forces acting between molecules of Non-polar molecular solids?

Options:
A Dipole-dipole interactions
B Dispersion or london forces
C Electrostatic forces
D Covalent bonding

The correct answer is:
Dispersion or london forces

Solution:
Correct Option is : 2
Dispersion or london forces

Topic: Chemistry, Solid State, NEET
Type of isomerism exhibited by compounds $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3,\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_5 \mathrm{Cl}^{\mathrm{Cl}} \mathrm{Cl}_2 \cdot \mathrm{H}_2 \mathrm{O},\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}_2 . \mathrm{H}_2 \mathrm{O}\right.$ and the value of coordination number $(\mathrm{CN})$ of central metal ion in all these compounds, respectively is:

Options:
A Ionisation isomerism, $\mathrm{CN}=4$
B Solvate isomerism, $\mathrm{CN}=6$
C Geometrical isomerism, $\mathrm{CN}=4$
D Optical isomerism, $\mathrm{CN}=4$

The correct answer is:
Solvate isomerism, $\mathrm{CN}=6$

Solution:
Solvate isomerism differ by whether or not a solvent molecule is directly bonded to the metal ion or merely present as free solvent molecules in the crystal lattice.
- $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3,\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_5 \mathrm{ClICl}_2 . \mathrm{H}_2 \mathrm{O}\right.$ and $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}_2 2 \mathrm{H}_2 \mathrm{O}$ show solvate isomerism.
- Co-ordination number of $\mathrm{Cr}=6$

Topic: Chemistry, Coordination Compounds, NEET, NEET 2023 (Manipur)
Type of joint allows for limited movement?

Options:
A Fibrous joint
B Cartilaginous joint
C Synovial joint
D None of the above

The correct answer is:
Cartilaginous joint

Solution:
Cartilaginous joints allow for limited movement. The joint between the adjacent vertebrae in the vertebral column is an example of this type of joint.

Topic: Biology, Locomotion and Movement, NEET
Type of joint present between carpel and metacarpal of thumb is

Options:
A Saddle joint
B Gliding joint
C Hinge joint
D Pivot joint

The correct answer is:
Saddle joint

Solution:
First carpo-metacarpel joint in thumb is a saddle joint. The saddle joint gets its name because the bone forming one part of the joint is concave (turned inwards) at one end and looks like a saddle. The other bone's end is convex (turned outwards) and looks like a rider in a saddle.

Topic: Biology, Locomotion and Movement, NEET
(+,-) type of population interaction is represented by:

Options:
A Clown fish and sea anemone
B Goat and Tortoise
C Mycorrhizae and Vascular plants
D Cuscuta and hedge plant

The correct answer is:
Cuscuta and hedge plant

Solution:
The (+,-) symbols can be applicable for both predation and parasitism. But according to the question, it is denoting parasitism. Parasites that feed on the external surface of the host organism are called ectoparasites. The most familiar examples of this group are lice on humans and ticks on dogs. Many marine fishes are infested with ectoparasitic copepods. Cuscuta, a parasitic plant that is commonly found growing on hedge plants, has lost its chlorophyll and leaves in the course of evolution. It derives its nutrition from the host plant which it parasitises.

Topic: Biology, Organisms and Populations, NEET
Typical silt (hard mud) particle of radius 20 Î¼m is on the top of lake water, its density is 2000 kg m-3 and the viscosity of lake water is 1.0 mPa, density is 1000 kg m-3. If the lake is still(has no internal fluid motion). The terminal speed with which the particle hits the bottom of the lake is .......... mm s-1

Options:
A 0.67
B 0.77
C 0.87
D 0.97

The correct answer is:
0.87

Solution:
v=29r2(Ï-Ï)gÉ³
= 2 9 Ã ( 20Ã 10 â6 ) 2 ( 2000â1000 )Ã9.8 1.0Ã 10 â3
=8.7Ã10-4 m s-1=0.87 mm s-1

Topic: Physics, Mechanical Properties of Fluids, NEET
Typically, gymnosperms lack

Options:
A Xylem vessels but sieve tubes are present
B Tracheids and sieve tubes but companion cells are present
C Vessels, sieve tubes and companion cells
D Tracheids and companion cells

The correct answer is:
Vessels, sieve tubes and companion cells

Solution:
Gymnosperms are first successful land plants which had vascular tissues. Xylem consists of Tracheids only for conduction and vessels are absent. Phloem consists sieve cells only, sieve tubes and companion cells are absent. Vessels, sieve tubes and companion cells are characteristics of angiosperms only.

Topic: Biology, Plant Kingdom, NEET
U92238 has 92 protons and 238 nucleons. It decays by emitting an alpha particle and becomes

Options:
A U92234
B Th90234
C U92235
D Np93237

The correct answer is:
Th90234

Solution:
Let the daughter nucleus be XZA . So, reaction can be shown as
U92238âXZA+He24
From conservation of atomic mass
238= A+4
â A=234
From conservation of atomic number
92=Z+2
â Z=90
So, the resultant nucleus is X90234 , i.e., Th90234.

Topic: Physics, Nuclear Physics, NEET
ΔU is equal to:

Options:
A Isobaric work
B Adiabatic work
C Isothermal work
D Isochoric work

The correct answer is:
Adiabatic work

Solution:
From the 1st law of Thermodynamics
ÎU=q+w
For adiabatic process
q=0,
So, ÎU=W

Topic: Chemistry, Thermodynamics (C), NEET
Uranium-238 decays to Thorium-234 with half-life 5Ã109 yr . The resulting nucleus is in the excited state and hence further emits Î³ -rays to come to the ground state. It emits 20 Î³ -rays per second. The emission rate will drop to 5 Î³-rays per second in

Options:
A 1.25Ã109Â yr
B 1010 yr
C 10-8Â yr
D 1.25Ã10-9Â s

The correct answer is:
1010 yr

Solution:
Number of emitted γ-rays per second is proportional to no of uranium particles left undecayed
fraction of particles undecayed, N N 0 = ( 1 2 ) n
Where n is the number of half-lives
⇒ 5 20 = ( 1 2 ) n
n=2
Total time =2×5× 10 9 years
= 10 10 yr

Topic: Physics, Nuclear Physics, NEET
Ulothrix and Spirogyra are:

Options:
A Colonial and branched
B Solitary and branched
C Filamentous and unbranched
D Filamentous and branched

The correct answer is:
Filamentous and unbranched

Solution:
Ulothrix and Spirogyra belong to the class Chlorophyceae, commonly called green algae. Ulothrix, found in freshwater and marine water, is generally found attached to the bed of water bodies. The cells are very long and broad and favour low temperature for growth. They attach themselves to the bed by a modified holdfast cell. Spirogyra on the other hand a free-living and form mass floating on surface of water bodies. They are generally found in freshwater region and named so due to their spiral form of chloroplast.
Both these groups of organisms from filaments of chain of cells and are unbranched. Both show vegetative reproduction by fragmentation.

Topic: Biology, Plant Kingdom, NEET
Ultrasound of how much frequency is beamed into human body for sonography?

Options:
A $15-30 \mathrm{MHz}$
B $1-15 \mathrm{MHz}$
C $45-70 \mathrm{MHz}$
D $30-45 \mathrm{MHz}$.

The correct answer is:
$1-15 \mathrm{MHz}$

Solution:
In sonography (ultrasound imaging), inaudible high frequency of sound waves in the range of $1-5 \mathrm{MHz}$ are used.
Related Theory
Sonography is a medical imaging technique that uses high-frequency sound waves to produce images of internal body structures. It is also known as ultrasound. After the $X$-ray test, ultrasound is the most used diagnostic imaging technique. It uses a device called a transducer to send out ultrasound waves and listen for the echo. A computer translates the ultrasound waves into an image. A trained technician can see, measure, and identify structures in the image.

Topic: Biology, Human Reproduction, NEET, NEET 2007