datavorous/entrance-exam-dataset huggingface dataset:
A train of 150 m length is going towards North direction at a speed of 10 ms-1. A parrot files at a speed of 5 ms-1 towards South direction parallel to the railway track. The time taken by the parrot to cross the train is equal to

Options:
A 12 s
B 8 s
C 15 s
D 10 s

The correct answer is:
10 s

Solution:
Relative velocity of the parrot w.r .t the train
=10--5ms-1
=15 ms-1
Time taken by the parrot to cross the train
=15015=10 s

Topic: Physics, Motion In Two Dimensions, NEET
A trait controlled by a gene at several loci is an example of

Options:
A Multiple allelism
B Incomplete dominance
C Pleiotropy
D Polygenic inheritance

The correct answer is:
Polygenic inheritance

Solution:
When a single trait is controlled by two or more than two genes present at different gene locus than the inheritance is known as polygenic inheritance. In this continuous phenotypic variation is observed in the phenotype.

Topic: Biology, Principles of Inheritance and Variation, NEET
A trangenic food crop' which may help in solving the problem of night blindness in developing countries is

Options:
A Flavr Savr tomatoes
B Starlink maize
C Bt Soybean
D Golden rice

The correct answer is:
Golden rice

Solution:
Golden rice is a transgenic food crop which may help in solving the problem of night blindness in developing countries. Golden rice or miracle rice is rich in vitamin A or β - carotene and iron and are also valuable achievements of gene transfer technology.

Topic: Biology, Biotechnology and Its Applications, NEET
A transcription unit in DNA is defined primarily by the three regions in DNA and these are with respect to upstream and down stream end;

Options:
A Structural gene, Transposons, Operator gene
B Inducer, Repressor, Structural gene
C Promotor, Structural gene, Terminator
D Repressor, Operator gene, Structural gene

The correct answer is:
Promotor, Structural gene, Terminator

Solution:
A transcription unit of DNA is defined primarily by the three regions in the DNA:
(i) A promoter
(ii) The structural gene
(iii) A terminator
The promoter is said to be located towards 5 '-end (upstream) of the structural gene (the reference is made with respect to the polarity of coding strand)
The terminator is located towards 3 '-end (downstream) of the coding strand.

Topic: Biology, Molecular Basis of Inheritance, NEET, NEET 2024
A transcription unit in DNA must have

Options:
A Promoter
B Structural gene
C Terminator
D All of the above

The correct answer is:
All of the above

Solution:
Transcription is the formation of RNA from DNA. The transcription unit consists of three regions, promoter to which RNA polymerase binds and initiates the transcription, structural gene which codes for mRNA and terminator which ends the process of transcription.

Topic: Biology, Molecular Basis of Inheritance, NEET
A transistor having current amplification Î² equal to 80 has a change in base current of 250 Î¼A , then the change in collector current is

Options:
A 170 Î¼A
B 330 Î¼A
C 3.125 Î¼A
D 20 mA

The correct answer is:
20 mA

Solution:
Using Î²=ÎIcÎIb
we get â ÎIc=ÎIbÃÎ²=250Ã80Î¼A
ÎIc=20 mA

Topic: Physics, Semiconductors, NEET
A transistor is connected in common emitter (CE) configuration. The collector supply is 8 V and the voltage drop across a resistor of 800 Î© in the collector circuit is 0.8 V. If the current gain factor Î± is 0.96, then the change in the base current is

Options:
A 124 mA
B 112 mA
C 16 mA
D 13 mA

The correct answer is:
124 mA

Solution:
According to the question :
α=0.96
β=α1-α=0.961-0.96=24
ΔIC=0.8800=10-3A
ΔIB=ΔlCβ=10324 A
=124 mA

Topic: Physics, Semiconductors, NEET
A transistor is operated in common emitter configuration at constant collector voltage \(\mathrm{V}_{\mathrm{c}}=1.5 \mathrm{~V}\) such that a change in the base current from \(100 \mu \mathrm{A}\) to \(150 \mu \mathrm{A}\) produces a change in the collector current from 5 mA to 10 mA. The current gain \((\beta)\) is:-

Options:
A 50
B 67
C 75
D 100

The correct answer is:
100

Solution:
Current gas $=\beta=\frac{\Delta I_C}{\Delta I_B}$
$$
\begin{aligned}
& =\frac{(10-5) \mathrm{mA}}{(150-100) \mathrm{mA}}=\frac{5 \times 10^{-3}}{50 \times 10^{-16}} \\
& =10 \mathrm{C}
\end{aligned}
$$

Topic: Physics, Semiconductors, NEET, NEET 2006
A transistor is operated in common emitter configuration at $V_C=2 \mathrm{~V}$ such that a change in the base current from $100 \mu \mathrm{A}$ to $300 \mu \mathrm{A}$ produces a change in the collector current from $10 \mathrm{~mA}$ to $20 \mathrm{~mA}$. The current gain is

Options:
A 75
B 100
C 25
D 50

The correct answer is:
50

Solution:
$\beta=\frac{\Delta I_C}{\Delta I_B}=\frac{(20-10) \mathrm{mA}}{(300-100) \mathrm{mA}}=\frac{10 \times 10^{-3}}{200 \times 10^{-6}}=50$

Topic: Physics, Semiconductors, NEET, NEET 2011 (Screening)
A transistor is operated in common-emitter configuration at $V_c=2$ volt such that a change in the base current from $100 \mu \mathrm{A}$ to $200 \mu \mathrm{A}$ produces a change in the collector current from $5 \mathrm{~mA}$ to $10 \mathrm{~mA}$. The current gain is

Options:
A 75
B 100
C 150
D 50

The correct answer is:
50

Solution:
For a transistor
$$
\begin{aligned}
& \text { where } \quad \begin{array}{l}
\mathrm{I}_{\mathrm{E}}=\mathrm{I}_{\mathrm{B}}+\mathrm{I}_{\mathrm{C}} \\
\mathrm{I}_{\mathrm{E}}=\text { emitter current } \\
\mathrm{I}_{\mathrm{B}}=\text { base current } \\
\mathrm{I}_{\mathrm{C}}=\text { collector current } \\
\text { and current gain } \beta=\frac{\Delta \mathrm{I}_{\mathrm{C}}}{\Delta \mathrm{I}_{\mathrm{B}}} \\
\Delta \mathrm{I}_{\mathrm{C}}=5 \times 10^{-3} \mathrm{~A} \\
\Delta \mathrm{I}_{\mathrm{B}}=100 \times 10^{-6} \mathrm{~A} \\
\beta=\frac{5}{100} \times 1000=50
\end{array}
\end{aligned}
$$

Topic: Physics, Semiconductors, NEET, NEET 2009 (Screening)
A transistor is used as a common emitter amplifier with a load resistance of 2 kÎ©. The input resistance is 150 Î©. Base current is changed by 20 Î¼A which results in a change in collector current by 1.5 mA. The voltage gain of the amplifier is

Options:
A 900
B 1000
C 1100
D 1200

The correct answer is:
1000

Solution:
Voltage gain =V0Vi=R0×∆ICRi×∆IB
= 2000×1.5× 10 −3 150×20× 10 −6 = 3 3000× 10 −6
= 1 ( 1000 ) −1 =1000

Topic: Physics, Semiconductors, NEET
A transistor is used as an amplifier in CB mode with a load resistance of 5 kâ¡Î©. The current gain of amplifier is 0.98 and the input resistance is 70 Î©. The voltage gain and power gain, respectively, are

Options:
A 70, 68.6
B 80, 75.6
C 60, 66.6
D 90, 96.6

The correct answer is:
70, 68.6

Solution:
α=ICIE=0.98
Vα=αRLRin=0.98×5×10370
Pα=α2RLRin=0.982×5×10370

Topic: Physics, Semiconductors, NEET
A transistor is used as an amplifier in common base mode with a load resistance of 5 kÎ©. If the current gain of amplifier is 0.98 and the input resistance is 70 Î©, then voltage gain and power gain respectively are

Options:
A 70, 68.6
B 80, 75.6
C 60, 66.6
D 90, 96.6

The correct answer is:
70, 68.6

Solution:
Current gain in common base mode
α=ICIE=0.98

Voltage gain AV=αRLRin=0.98×5×10370
⇒AV=70
Power gain AP=a2RLRin=0.982×5×10370
⇒AP=68.6

Topic: Physics, Semiconductors, NEET
A transistor is used as an amplifier in common base mode with a load resistance of 5 kÎ©. The current gain of the amplifier is 0.98 and the input resistance is 70 kÎ©, the voltage gain is

Options:
A 70

B 80

C 60

D 90

The correct answer is:
70

Solution:
Here, in common base mode Î±=0.98,
R=5 k Î©=5Ã103
Rin=70 Î©
Voltage gain
AV=Î±ÃRRin=0.98Ã5Ã10370=70

Topic: Physics, Semiconductors, NEET
A transistor is used as an amplifier in common base mode with a load resistance of 5 kâ¡Î©. The current gain of the amplifier is 0.98 and the input resistance is 70 Î©. The voltage gain and power gain respectively are

Options:
A 70, 68.6
B 80, 75.6
C 60, 66.6
D 90, 96.6

The correct answer is:
70, 68.6

Solution:
α=ICIE=0.98
Vα=αRLRin=0.98×5×10370
Vα=70
Pα=α2RLRin=0.982×5×10370
Pα=68.6

Topic: Physics, Semiconductors, NEET
A transistor oscillator is
(i) An amplifier with positive feedback
(ii) An amplifier with reduced gain
(iii) The one in which DC supply energy is converted into AC output energy. Then

Options:
A All (i), (ii) and (iii) are correct
B (i) and (ii) are correct
C (i) and (iii) are correct
D (ii) and (iii) are correct

The correct answer is:
(i) and (iii) are correct

Solution:
A transistor oscillator is an amplifier with positive feedback.
A transistor oscillator is the one in which DC supply energy is converted into AC output energy.

Topic: Physics, Semiconductors, NEET
A transistor-oscillator using a resonant circuit with an inductor $L$ (of negligible resistance) and a capacitor $C$ in series produce oscillations of frequency $f$. If $L$ is doubled and $C$ is changed to $4 \mathrm{C}$, the frequency will be:

Options:
A $f / 2$
B $f / 4$
C $7 \times 10^{-24}$
D $10^{-22}$

The correct answer is:
$10^{-22}$

Solution:
According to the question
and
$\begin{aligned}
f & =\frac{1}{2 \pi \sqrt{\mathrm{LC}}} \\
f^{\prime} & =\frac{1}{2 \pi \sqrt{2 \mathrm{LC} 4 \mathrm{~V}}} \\
f^{\prime} & =\frac{1}{2 \sqrt{2}} \quad \frac{1}{2 \pi \sqrt{L C}} \\
& =\frac{f}{2 \sqrt{2}}
\end{aligned}$

Topic: Physics, Semiconductors, NEET, NEET 2006
A transition metal complex shows a magnetic moment of 5.9 B.M. at room temperature. The number of unpaired electron on the metal is

Options:
A 3
B 4
C 5
D 2

The correct answer is:
5

Solution:
Magnetic moment =n(n+2)B.M.
5.9 = n(n+2)
on solving n = 5.

Topic: Chemistry, Coordination Compounds, NEET
A transparent plastic bag filled with air forms a concave lens. Now, if this bag is completely immersed in water, then it behaves as

Options:
A Divergent lens
B Convergent lens
C Equilateral prism
D Rectangular slab

The correct answer is:
Convergent lens

Solution:
In air 1 f =( μ p −1 )( 1 R 1 − 1 R 2 )
In water 1 f =( μ p μ ω −1 ) ( 1 R 1 − 1 R 2 )
as retractive index of water is more than retractive index of plastic bag filled with air
∴ If behave as convergent lens

Topic: Physics, Ray Optics, NEET
A transparent solid cylindrical rod has a refractive index of 23. It is surrounded by air. A light ray is incident at the midpoint of one end of the rod as shown in the figure. The incident angle θ for which the light ray grazes along the wall of the rod is

Options:
A sin-1⁡12
B sin-1⁡32
C sin-1⁡23
D sin-1⁡13

The correct answer is:
sin-1⁡13

Solution:
From Snell's law,
μairsinθ=μcylidersin 90°–θC
⇒1×sinθ=23×cosθC
But, sin⁡θC=1μcylinder=32
Therefore cos⁡θC=12
⇒sinθ=23.12=13
⇒θ=sin–1⁡13

Topic: Physics, Ray Optics, NEET
A transverse harmonic wave on a string is described by y(x, t) = 3.0 sin (36 t + 0.018 x + π/4) where x and y are in cm and t in s. The positive direction of x is from left to right. Which type of wave is described by the given equation for y(x, t)?

Options:
A Travelling wave
B Stationary wave
C Longitudinal wave
D Sound wave

The correct answer is:
Travelling wave

Solution:
Correct Option is : (A)
Travelling wave

Topic: Chemistry, Waves and Sound, NEET
A transverse section of a plant material shows the following anatomical features under a microscope:
Thick cuticle, Sunken stomata, discontinuous sclerenchymatous hypodermis, Armed parenchyma, 'T' shaped sclerenchymatous girdle, Two-conjoint, collateral and open vascular bundle.

The plant material must be a

Options:
A Cycas rachis
B Cycas leaflet
C Pinus needle
D Nerium leaf

The correct answer is:
Pinus needle

Solution:
Pinus needle have thick cuticle, they have sunken stomata and have resin duct beneath the cuticle hence their hypodermis is discontinuous, pinus can be haploxylon i.e., one fibrovascular bundle or diploxylon i.e., two fibro vascular bundle. Hence the above given transverse section is of pinus needle.

Topic: Biology, Anatomy of Flowering Plants, NEET
A transverse wave along a string is given by y=2sinâ¡2Ï3t-x+Ï4, where, x and y are in cm and t in second. Find the acceleration of a particle located at x=4 cm at t=1 s.

Options:
A 362 π2 cm s-2
B 36π2 cm s-2
C -362 Ï2 cm s-2
D -36π2 cm s-2

The correct answer is:
-362 Ï2 cm s-2

Solution:
We know that v=dydt
=ddt 2sinâ¡2Ï3t-x+Ï4
a=dvdt=ddt12Ïcosâ¡2Ï3t-x+Ï4
a=-72Ï2sinâ¡2Ï3t-x+Ï4
at t=1 and x=4 cm
a=-36 2Ï2 cm s-2

Topic: Physics, Waves and Sound, NEET
A transverse wave is described by the equation y=y0 sin2Ïft-xÎ».The maximum particle velocity is equal to four times the wave velocity if

Options:
A λ=πy04
B Î»=2Ïy0
C λ=πy0
D λ=πy02

The correct answer is:
λ=πy02

Solution:
dydt=y0cosâ¡2Ïft-xÎ»Ã2Ïf
â´ maximum particle velocity =dydtmax=2Ïfy0Ã1
Wave velocity =fÎ»
As 2Ïfy0=4fÎ», â´ Î»=2Ïy04=Ïy02

Topic: Physics, Waves and Sound, NEET
A transverse wave is represented by $y=A \sin (\omega t-k x)$. For what value of the wavelength is the wave velocity equal to the maximum particle velocity?

Options:
A $\pi \mathrm{A} / 2$
B $\pi \mathrm{A}$
C $2 \pi \mathrm{A}$
D $\mathrm{A}$

The correct answer is:
$2 \pi \mathrm{A}$

Solution:
Wave velocity $\mathrm{v}=\frac{\lambda}{\mathrm{T}}=\frac{\omega \lambda}{2 \pi}$
Maximum particle velocity $\left(v_{\max }\right)_p=A \omega$
Given,
$$
\begin{aligned}
& \mathrm{v}=\left(\mathrm{v}_{\max }\right)_p \\
& \frac{\omega \lambda}{2 \pi}=A \omega \\
& \Rightarrow \quad \lambda=2 \pi \mathrm{A} \\
&
\end{aligned}
$$

Topic: Physics, Waves and Sound, NEET, NEET 2010 (Screening)
A transverse wave is represented by y = A sin(Ït â kx). For what value of the wavelength is the wave velocity equal to the maximum particle velocity?

Options:
A πA2
B πA
C 2πA

D A

The correct answer is:
2πA

Solution:
The given wave equation is
y = Asin(ωt – kx)
Wave velociy,v=ωk…i
Particle velocity,vp⁡=d⁡yd⁡t=A⁡ωcosωt-kx
Maximum particle velocity, vpmax=Aω ...(ii)
According to the given question
v=vpmax
ω k = A⁡ ω Using (i) and (ii)
1 k = A⁡
or λ 2 π = A⁡ ∵ k = 2 π λ
λ = 2πA

Topic: Physics, Waves and Sound, NEET
A transverse wave pulse is generated at the free end of a string which is hanging from a rigid support. The speed of the wave pulse at distance x from the free end is proportional to

Options:
A x2
B x
C x
D 1x

The correct answer is:
x

Solution:
At x distance from end
Velocity in string = Tension Mass per unit length
v=TÎ¼
v=Î¼xgÎ¼
v=xg
vâx

Topic: Physics, Waves and Sound, NEET
A travelling wave passes a point of observation. At this point, the time interval between successive crests is 0.2 s and

Options:
A the wavelength is 5 m
B the frequency is 5 Hz
C the velocity of propagation is 5Â m/s
D the wavelength is 0.2 m

The correct answer is:
the frequency is 5 Hz

Solution:
Phase difference between two successive crest is 2π.
Also, phase difference Δϕ=2πT×Δt
⇒ 2π=2πT×0.2
⇒ 1T=5 s-1
⇒n=5 Hz

Topic: Physics, Waves and Sound, NEET
A travelling wave represented by y= A sinâ¡(Ït-kx) is superimposed on another wave represented by y=Asinâ¡(Ït+kx). The resultant is:

Options:
A A standing wave having nodes at x=n+12Î»2 , n=0, 1, 2, â¦
B A wave travelling along +x direction
C A wave travelling along -x direction
D A standing wave having nodes at x=nÎ»2;n=0,Â 1,Â 2

The correct answer is:
A standing wave having nodes at x=n+12Î»2 , n=0, 1, 2, â¦

Solution:
From given progressive waves produced stationary wave
ysw=A [sinâ¡wt-kx+sinâ¡(wt+kx)]
ysw=2Acosâ¡kxsinâ¡wt
At x=0,Î»2, Î»â¦âysw=2a= Antinode
At x=Î»4,3Î»4.. âysw=0= Nodes

Topic: Physics, Waves and Sound, NEET
A triploid angiosperm is

Options:
A highly fertile
B normal
C sterile
D sterile and seedless

The correct answer is:
sterile and seedless

Solution:
Triploids develop due to combination of diploid gamete with a haploid gamete. Such zygote will have three sets of chromosomes. Such progenies are found to be infertile as they have uneven number of chromosomes sets which will not pair correctly during the meiosis process. They wont be able to produce seed as well.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
A truck is stationary and has a bob suspended by a light string, in a frame attached to the truck. The truck, suddenly moves to the right with an acceleration of a. The pendulum will tilt

Options:
A to the left and the angle of inclination of the pendulum with the vertical is $\sin ^{-1}\left(\frac{g}{a}\right)$
B to the left and angle of inclination of the pendulum with the vertical is $\tan ^{-1}\left(\frac{a}{g}\right)$
C to the left and angle of inclination of the pendulum with the vertical is $\sin ^{1-}\left(\frac{a}{g}\right)$
D to the left and angle of inclination of the pendulum with the vertical is $\tan ^{-1}\left(\frac{g}{a}\right)$

The correct answer is:
to the left and angle of inclination of the pendulum with the vertical is $\tan ^{-1}\left(\frac{a}{g}\right)$

Solution:
As the truck move to the right, so the bob will move to the left due to inertia of rest with acceleration a.
Thus, the given situation can be drawn as
From the above diagram (b) as the string moves by an angle of $\theta$ with the vertical then the tangent angle is
$$
\tan \theta=\frac{\mathrm{ma}}{\mathrm{mg}} \Rightarrow \theta=\tan ^{-1}\left(\frac{\mathrm{a}}{\mathrm{g}}\right)
$$

Topic: Physics, Oscillations, NEET, NEET 2019 (Odisha)
A truck of mass 10 metric ton runs at 3 m s-1 along a level track and collides with a loaded truck of mass 20 metric ton, standing at rest. If the trucks couple together, the common speed after the collision is

Options:
A 1 m s-1
B 0.1Â ms-1
C 0.5Â ms-1
D 0.3Â ms-1

The correct answer is:
1 m s-1

Solution:
By the conservation of linear momentum
v=m1u1+m2u2m1+m2
v=10×3+20×010+20=1 m s-1

Topic: Physics, Center of Mass Momentum and Collision, NEET
A truck travelling due north at 20 m/s turns west and travels at the same speed. The change in its velocity is

Options:
A 40 m s-1 N-W
B 202 m s-1 N-W
C 40 m s-1 S-W
D 202 m s-1 S-W

The correct answer is:
202 m s-1 S-W

Solution:
The representative figure for the problem is given below:-
From the diagram
vâ1=20 i^ and v2â=-20 i^
Therefore change in velocity is
Îvâ=v2â-v1â=-20 i^+j^
Magnitude of change in velocity
Îvâ=202 and direction is Î¸=tan-11=45o i.e. S-W

Topic: Physics, Motion In One Dimension, NEET
A true breeding plant is:

Options:
A One that is able to breed on its own
B Produced due to cross-pollination among unrelated plants
C Near homozygous and produces offspring of its own kind
D Always homozygous recessive in its genetic constitution

The correct answer is:
Near homozygous and produces offspring of its own kind

Solution:
The true breeding line is one that, having undergone continuous self-pollination, shows the stable trait inheritance and expression for several generations. It is both homozygous recessive as well as dominant in the genetic constitution.

Topic: Biology, Principles of Inheritance and Variation, NEET, NEET 2016 (Phase 2)
A tube of length $L$ is filled completely with an incompressible liquid of mass $M$ and closed at both the ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity $\omega$. The force exerted by the liquid at the other end is:

Options:
A $\frac{M L^2 \omega^2}{2}$
B $\frac{M L \omega^2}{2}$
C $\frac{M L^2 \omega}{2}$
D $M L \omega^2$

The correct answer is:
$\frac{M L \omega^2}{2}$

Solution:
$\therefore$ Centrifugal force $=M \omega^2 r$
$$
\begin{aligned}
& =M\left(\frac{1}{2}\right) \omega^2 \\
& =\frac{M L \omega^2}{2} .
\end{aligned}
$$

Topic: Physics, Mechanical Properties of Fluids, NEET, NEET 2006
A tube of length L is filled completely with an incompressible liquid of mass M and closed at both the ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity ω. The force exerted by the liquid at the other end is

Options:
A Mω2L2
B MLω2
C MLω24
D ML2ω22

The correct answer is:
Mω2L2

Solution:
Taking a small element : thus the force excreted by this element is dF then.
dF=dmω2x
dm=MLdx
integrating we get
∫0FdF=∫0LMLω2xdx
F= M L ω 2 ( x 2 2 ) 0 L
F=Mω2L2

Topic: Physics, Laws of Motion, NEET
A tumour inducing autonomously replicating circular extra-chromosomal DNA widely used in development of transgenic plant is that of

Options:
A Escherichia coli
B Bacillus thuringiensis
C Staphylococcus aureus
D Agrobacterium tumefaciens

The correct answer is:
Agrobacterium tumefaciens

Solution:
Ti plasmid of Agrobacterium is natural gene transfer tool used by the bacteria to induce tumor into the host plant. The Ti plasmid is used as a vector to transfer the gene of interest into the plant and develop transgenic plant.

Topic: Biology, Biotechnology - Principles and Processes, NEET
A tuning fork is in resonance with a vibrating string under tension. When the tuning fork is moved with a certain velocity, 2 beats per second are heard. If the tension is increased, the beats disappear again. The direction of motion of the tuning fork is

Options:
A towards the string
B away from the string
C random
D unpredictable as data is not sufficient

The correct answer is:
towards the string

Solution:
When tension is increased the frequency of the string increases from n to n + ân . This means apparent frequency of the tuning fork has also increased from n to n+ân . So the tuning fork is moving towards the string.

Topic: Physics, Waves and Sound, NEET
A tuning fork is used to produce resonance in glass tube. The length of the air column in this tube can be adjusted by a variable piston. At room temperature of 27 oC two successive resonances are produced at 20 cm and 73 cm of column length. If the frequency of the tuning fork is 320 Hz, the velocity of sound in air at 27 oC is

Options:
A 350 m s-1
B 339 m s-1
C 330 m s-1
D 300 m s-1

The correct answer is:
339 m s-1

Solution:
In resonance tube experiment,
Speed of sound v=2fl2-l1
=2320×0.73-0.20
= 640×0.53=339.2 m s-1

Topic: Physics, Waves and Sound, NEET, NEET 2018
A tuning fork makes 256 vibrations per second in air. When the velocity of sound is 330 m/s, then wavelength of the tone emitted is

Options:
A 0.56Â m
B 0.89Â m
C 1.11Â m
D 1.29 m

The correct answer is:
1.29 m

Solution:
v=nÎ»
â Î»=vn=330256=1.29 m

Topic: Physics, Waves and Sound, NEET
A tuning fork of 480 Hz causes an open-ended organ pipe of length L to vibrate in its first harmonic. What should be the length of a pipe closed at one end, so that it also vibrates in its first harmonic with the same tuning fork?

Options:
A L/2
B L/4
C 2L
D 4L

The correct answer is:
L/2

Solution:
Correct Option is : (A)
L/2

Topic: Chemistry, Waves and Sound, NEET
A tuning fork of frequency 100 Hz when sounded together with another tuning fork of unknown frequency produces 2 beats per second. On loading the tuning fork whose frequency is not known and sounded together with a tuning fork of frequency 100 Hz produces one beat, then the frequency of the other tuning fork is

Options:
A 102
B 98
C 99
D 101

The correct answer is:
102

Solution:
Suppose nA is known frequency, then nA=100 Hz, and let nB be the frequency of the other tuning fork
x=2=Beat frequency, which is decreasing after loading (i.e. x↓)
Unknown tuning fork is loaded so nB decreases and also given that beat frequency is 1, so beat frequency also decreases
Hence, nB>nA and nB-nA =x
⇒nB=nA+x=100+2=102 Hz

Topic: Physics, Waves and Sound, NEET
A tuning fork of frequency 200 Hz is in unison with a sonometer wire. Tension in the wire of sonometer is increased by 1% without any change in its length. Find the number of beats heard in 9 s.

Options:
A 9
B 3
C 6
D 12

The correct answer is:
9

Solution:
f=12πTμ
∆ff=12∆TT
∆f=12×1100×200
∆f=1
Beat frequency = 1
Number of beats in 9 second =9×1=9

Topic: Physics, Waves and Sound, NEET
A tuning fork of frequency 480 Hz produces 10 beats s-1 when sounded with a vibrating sonometer string. What must have been the frequency of string if slight increase in tension produces fewer beats s-1 than before?

Options:
A 490 Hz
B 470 Hz
C 460 Hz
D 480 Hz

The correct answer is:
470 Hz

Solution:
Here n1=480,m=10
n2=n1±m=480±10=490 or 470
When tension is increased, n2 will increase
(∴n2∝T).
As number of beats s-1 decrease, n2=470 Hz

Topic: Physics, Waves and Sound, NEET