datavorous/entrance-exam-dataset huggingface dataset:
A stream of electrons from heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron respectively, then the value of h/λ (where λ is wavelength associated with electron wave) is given by

Options:
A 2meV
B meV
C 2meV
D meV

The correct answer is:
2meV

Solution:
As electron of charge 'e' is passed through 'V' volt, kinetic energy of electron becomes ='eV'
As wavelength of e- wave (λ)=h2m.K.E.
λ=h2meV
So hλ=2meV

Topic: Chemistry, Structure of Atom, NEET
A stream of electrons is projected horizontally to the right. A straight conductor carrying a current is supported parallel to electron stream and above it. If the current in the conductor is from left to right, then what will be the effect on electron stream?

Options:
A The electron stream will be speeded up towards the right
B The electron stream will be retarded
C The electron stream will be pulled upwards
D The electron stream will be pulled downwards

The correct answer is:
The electron stream will be pulled downwards

Solution:
Magnetic field due to current through a linear conductor from the left to right at a point below the conductor is acting horizontally upwards. The electron beam moving from left to right will cause the current right to left. The force on the electrons will be vertically downwards according to Fleming's hand rule.

Topic: Physics, Magnetic Effects of Current, NEET
A stream of electrons is projected horizontally to the right. A straight current-carrying conductor is supported parallel to the electron stream and above it. If the current in the conductor is from left to right, what will be the effect on the electron stream?

Options:
A the electron stream will be pulled upwards
B the electron stream will be pulled downwards
C the electron stream will be retarded
D the electron stream will be speeded up towards the right

The correct answer is:
the electron stream will be pulled downwards

Solution:
Magnetic field due to wire at electron stream is in +y direction
the velocity of e is in +i^
∴ Force on electrons, F→=qv→×B→
The direction of this force is =-i^×j^=-k^

Topic: Physics, Magnetic Effects of Current, NEET
A stream of non-viscous liquid emerges from a very short outlet tube at the base of a large open tank, in which the depth of liquid is h. The tube is at a fixed angle θ to the ground as shown in the figure. The maximum height of the stream y is

Options:
A h sin2â¡Î¸
B h sin2θ
C 12 hsinâ¡Î¸
D h tan2â¡Î¸

The correct answer is:
h sin2â¡Î¸

Solution:
Let the speed of fluid at outlet is v .
Applying Bernoulli's theorem,
p1+Ïgh+12Ïv2=constant
p0+Ïgh+0=p0+0+12Ïv2
â´v=2gh ...(i)
At outlet,
vsinâ¡Î¸ vertical velocity of the fluid at outlet,
v2=u2+2gh1
For maximum height,
0=vsinâ¡Î¸2-2gh1
â´h1=v2sin2â¡Î¸2g
=2ghsin2â¡Î¸2g [from Equation (i)]
=hsin2â¡Î¸
h1=hsin2â¡Î¸

Topic: Physics, Mechanical Properties of Fluids, NEET
A stream of water flowing horizontally with the speed of 15 m s-1 gushes out of a tube of cross-sectional area 10-2 m-2 and hits a vertical wall normally. What is the force exerted on the wall by the impact of water?
Assuming it does not rebound.

Options:
A 2250 N
B 2000 N
C 1500 N
D 1000 N

The correct answer is:
2250 N

Solution:
Area of the cross-section of the tube, a=10-2 m-2
Speed of stream of water =15 m s-1
V= The volume of water coming out per second from the tube =a×v=15× 10-2 m3 s-1
Also, we know that the density of water striking the wall per second, then
m=pV=103×15×10-2 kg s-1=150 kg s-1
As on hitting the wall, water does not rebound, so
F= change in momentum per second
= mass of water flowing out per second × velocity
= 150×15=2250 N

Topic: Physics, Mechanical Properties of Fluids, NEET
A stream of water of density ρ, cross-sectional area A, and speed u strikes a wall that is perpendicular to the direction of the stream, as shown in the figure below. The water then flows sideways across the wall. The force exerted by the stream on the wall is

Options:
A ρu2A
B ρuA/2
C 3ρu2A
D u2A/ρ

The correct answer is:
ρu2A

Solution:
F=dpdt
F=dmudt=dmdtu
dmdt=ddtρAx=ρAdxdt
=ρAu
F=ρAuu
F=ρAu2

Topic: Physics, Center of Mass Momentum and Collision, NEET
A stretched string of length 1 m fixed at both ends, when vibrated in one loop has a frequency 200 Hz. It is now plucked at a point situated at 25 cm from one end. The stretched string would vibrate with a frequency of

Options:
A 100 Hz
B 200 Hz
C 400 Hz
D 800 Hz

The correct answer is:
400 Hz

Solution:
At a point of plucking, antinode is formed. At the fixed end of the string, node is formed. The separation between node and antinode =25 cm.
⇒λ4=25 cm
λ=100 cm
So string vibrates in p=2lλ loops
=2×100100=2 loops
New frequency n′=2n
=2×200
=400 Hz

Topic: Physics, Oscillations, NEET
A stretched string of length L, fixed at both ends can sustain stationary waves of wavelength λ. Which of the following value of wavelength is not possible?

Options:
A 2L
B 4L
C L
D L2

The correct answer is:
4L

Solution:
For a string of length L the maximum possible wavelength can be 2L.

Topic: Physics, Waves and Sound, NEET
A string is clamped at both the ends and it is vibrating in its 4th harmonic. The equation of the stationary wave is y=0.3sinâ¡0.157x cos(200Ït). The length of the string is
(All quantities are in SI units.)

Options:
A 20Â m
B 60Â m
C 40Â m
D 80 m

The correct answer is:
80 m

Solution:
From the equation, k=0.157
2πλ=0.157
λ=40 m
But, length of the wire in 4th harmonic, l=4×λ2=2λ=80 m.

Topic: Physics, Waves and Sound, NEET
A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencier between these two. The lowest resonant frequency for this string is:

Options:
A 205 Hz
B 10.5 Hz
C 105 Hz
D 155 Hz

The correct answer is:
105 Hz

Solution:
Two consecutive resonant frequencies for a string fixed at both ends will be
nv2l and n+1v2l
⇒ n+1v2l-nv2l=420-315
v2l=105 Hz
Which is the minimum resonant frequency.

Topic: Physics, Waves and Sound, NEET, NEET 2015 (Phase 2)
A string is tied at two rigid supports. A pulse is generated on the string as shown in figure. Minimum time after which string will regain its shape as shown in figure (Neglect the time during reflection)

Options:
A 2 s
B 4 s
C 6 s
D none of these

The correct answer is:
6 s

Solution:
At the shape of pulse gets inverted. The pulse will become erect after reflection at A. So the wave has to travel one complete round i.e. 12 m to regain its shape as the original. Therefore minimum time is,
tmin=dv
tmin=122=6 s

Topic: Physics, Waves and Sound, NEET
A string is vibrating in its fifth overtone between two rigid supports 2.4 m apart. The distance between successive node and antinode is

Options:
A 0.1 m
B 0.2 m
C 0.6 m
D 0.8 m

The correct answer is:
0.2 m

Solution:
Fifth overtone = Sixth harmonic
2.4=6 Î» 2
Î» 2 =0.4 m
Î» 2 =0.4
Î»=0.8
Î» 4 = 0.8 4
=0.2 m

Topic: Physics, Waves and Sound, NEET
A string of density 7.5 g cm-3 and area of cross-section 0.2 mm2 is stretched under a tension of 20 N. When it is plucked at the mid-point, the speed of the transverse wave on the wire is

Options:
A 116 m s-1
B 40 m s-1
C 200 m s-1
D 80 m s-1

The correct answer is:
116 m s-1

Solution:
The speed of the transverse wave
v=Tμ
Given, T=20 N,
M l⁡=d×A l⁡ l⁡=d×A
∴=207.5×0.2×10-32
v≈116 m s-1

Topic: Physics, Waves and Sound, NEET
A string of density 7.5 g cm-3 and area of cross-section 0.2 mm2 is stretched under a tension of 20 N. When it is plucked at the mid-point, the speed of the transverse wave on the wire is

Options:
A 116 m s-1
B 40Â m s-1
C 200Â m s-1
D 5900Â m s-1

The correct answer is:
116 m s-1

Solution:
The speed of transverse wave,
v=Tm
Given, T=20 N
Ml=d×All=d×A
∴ v=20×10-37.5×0.2×10-32
v≈116 m s-1

Topic: Physics, Waves and Sound, NEET
A string of density 7.5âgâ cm -3 and area of cross-section 0.2 mm2 is stretched under a tension of 20âN. When it is plucked at the mid-point, the speed of the transverse wave on the wire is

Options:
A 116 m s-1
B 40Â m s-1
C 200Â m s-1
D 5900Â m s-1

The correct answer is:
116 m s-1

Solution:
The speed of transverse wave,
v=Tm
Given, T=20 N
Ml=d×All=d×A
∴ v=20×10-37.5×0.2×10-32
v≈116 m s-1

Topic: Physics, Waves and Sound, NEET
A string of length 2x is stretched by 0.1 x and the velocity of a transverse wave along it is v. When it is stretched by 0.4x, the velocity of the wave is

Options:
A 56v
B 117v
C 327v
D 276v

The correct answer is:
327v

Solution:
Wave speed v=Tμ=TLM
v2v1=T2L2T1L1=kx2l0+x2kx1l0+x1
v2v1=0.4x2x+0.4x0.1x2x+0.1x
v2v=424121=327
v2=327v

Topic: Physics, Waves and Sound, NEET
A string of length 7 m has a mass of 0.035 kg . If tension in the string is 60.5 N , then speed of a wave on the string is

Options:
A 77 m/s
B 102 m/s
C 110 m/s
D 165m/s

The correct answer is:
110 m/s

Solution:
speed of a wave on the string is,
v=TÎ¼
Linear mass density is, Î¼=0.0357
Î¼=5Ã10-3 kg/m
â´ v=60.55Ã10-3
v=12.1Ã103
v=110 m/s

Topic: Physics, Waves and Sound, NEET
A string of mass 2.50 kg is under a tension of 200 N. The length of the stretched string is 20 m. if the transverse jerk is struck at one end of the string, how long does the disturbance take to reach the other end?

Options:
A 0.50 s
B 0.20 s
C 0.10 s
D 0.40 s

The correct answer is:
0.50 s

Solution:
Velocity of transverse wave
vâ¡ = Tâ¡ Î¼
where, T = tension in the string = 200 N
Î¼= mass per unit length
= Mass Length = 2 Â· 5 0 2 0 = 0 Â· 1 2 5 kg/m
vâ¡ = 2 0 0 0 Â· 1 2 5 = 1 6 0 0 = 4 0 m/s
Time taken by the disturbance to reach the other end
t = lâ¡ vâ¡ = 2 0 4 0 = 0 Â· 5 0 s

Topic: Physics, Waves and Sound, NEET
A string of mass 2.5 kg is under a tension of 200 N. The length of the stretched string is 20.0 m. If the transverse jerk is struck at one end of the string. How long does the disturbance take to reach the other end?

Options:
A 0.5 s
B 1Â s
C 1.5Â s
D 2Â s

The correct answer is:
0.5 s

Solution:
V=Tm
V=2000.125
V=40 m s-1
t=dV
t=2040
t=0.5 s

Topic: Physics, Waves and Sound, NEET
A string of mass per unit length 0.2 kg m-1 and length 0.6 m is fixed at both ends such that it has a tension of 80 N. If the string is vibrating in its second overtone mode, then the frequency of the string is

Options:
A 40 Hz
B 50 Hz
C 60 Hz
D 70 Hz

The correct answer is:
50 Hz

Solution:
v = T Î¼ = 80 0.2 = 20 m/s
3 Î» 2 = 0.6 m
â´ Î» = 0.4 m
fâ¡ = v Î» = 50 Hz

Topic: Physics, Units and Dimensions, NEET
A strip of copper is dipped into a colourless solution of the following four salts, which are placed separately in four different test tubes. Which solution will turn Blue?

Options:
A KNO3
B ZnSO4
C Zn(NO3)2
D AgNO3

The correct answer is:
AgNO3

Solution:
When a strip of copper is dipped in the solution of silver nitrate, the solution becomes blue.
Cu is placed above Ag in electrochemical series.
2AgNO3+Cu→Cu(NO3)2+2Ag

Topic: Chemistry, Electrochemistry, NEET
A strong base can abstract an $\alpha$-hydrogen from

Options:
A alkene
B amine
C ketone
D alkane

The correct answer is:
ketone

Solution:
Key Idea : The carbon which is more electrophilic in nature, loses an $\alpha-\mathrm{H}$ with a base more readily.
Among the given compounds, carbonyl carbon ($>\mathrm{C}=\mathrm{O}$) ie, ketone is more electrophilic in nature, thus loses an $\alpha-\mathrm{H}$ with a base $e g$, in aldol condensation reaction $\alpha$-hydrogen atom of aldehyde or ketone is abstracted by a strong base.

Topic: Chemistry, General Organic Chemistry, NEET, NEET 2008 (Screening)
A structure of a neuron is given in the diagram below. Select the incorrect statement with reference to the same.

Options:
A A typical neuron comprises of only three parts - A, C and E.
B B represents the granular bodies or Nissl's granules found in the cyton of the neuron.
C D are located on E, which secrete F.
D H possesses both dendrites and neurotransmitters.

The correct answer is:
H possesses both dendrites and neurotransmitters.

Solution:
A - dendrites
B - Nissl's granules
C - cyton or cell body
D - Schwann cell
E - Axon
F - Myelin sheath
H - Synaptic knob
Axon is a long fibre which is branched at its distal end and each branch ends into a bulb-like structure, which is termed as synaptic knob having synaptic vesicles filled with neurotransmitters. These neurotransmitters are released into the synapse between two consecutive axons. They are accepted by the receptors present on the membrane of the receiving axon.

Topic: Biology, Neural Control and Coordination, NEET
A student comes across the following symbol in a pedigree chart. The disease is definitely:

Options:
A Autosomal dominant
B Autosomal recessive
C X linked dominant
D X linked recessive

The correct answer is:
Autosomal recessive

Solution:
The given symbol is of a carrier male. Carriers only occur in recessive diseases. Males are never carriers in X-linked diseases because they have only one X chromosome. Thus, this symbol can be present in autosomal recessive disease only.

Topic: Biology, Principles of Inheritance and Variation, NEET
A student forgot to add the reaction mixture to the round bottomed flask at 27°C but instead he/she placed the flask on the flame. After a lapse of time, he realized his mistake, and using a pyrometer he found the temperature of the flask was 477°C. What fraction of air would have been expelled out?

Options:
A 1/5
B 2/5
C 3/5
D 4/5

The correct answer is:
3/5

Solution:
Correct Option is : (C)
3/5

Topic: Chemistry, States of Matter, NEET
A student is about to appear for an examination in the next half an hour. He is extremely anxious. His face is flushed and his heartbeat has increased. Which of the following could be a probable reason for this?

Options:
A Secretion of sleep-regulating hormones by the pineal gland
B Secretion of glucocorticoids by the adrenal cortex
C Secretion of TSH by the thyroid gland
D Secretion of emergency hormones by the adrenal medulla

The correct answer is:
Secretion of emergency hormones by the adrenal medulla

Solution:
The adrenal medulla is responsible for secretion of hormones 'adrenaline' and 'noradrenaline', collectively known as 'catecholamines'. These hormones are also called as 'hormones of fight or flight' or 'emergency hormones'. They are responsible for the increase in heartbeat, respiratory rate, etc., in times of emergency situations in response to stress.

Topic: Biology, Chemical Coordination and Integration, NEET
A Student is unable to answer a question on Newton's laws of motion attempts to pull himself up by tugging on his hair. He will not succeed :

Options:
A As the force exerted is small
B The frictional force while gripping, is small
C Newton's law of inertia is not applicable to living beings.
D As the force applied is internal to the system

The correct answer is:
As the force applied is internal to the system

Solution:
In this case internal force is applied on the system, so he will not succeed. According to Newton's law the state of a body can only be changed if some external force is applied on it.

Topic: Physics, Laws of Motion, NEET
A student made the following significant observation for the given cell sample. Cell has large quantities of rough endoplasmic reticulum and many Golgi bodies. Which type of cell can it be?

Options:
A Guard Cell
B Bacterium
C Lymphocyte
D Mesophyll

The correct answer is:
Lymphocyte

Solution:
Bacterium is a prokaryote, thus having an organelle like RER and GB is out of question. Presence of high amount of RER and GB indicates high production of protein. Guard cell is part of stomata which works by imbibing and releasing water, supporting in opening and closing of stomata. Mesophyll part of leaf in plant contains high amount of chlorophyll thus, involved in starch production than protein. Lastly, lymphocyte, a type of WBC is involved in making antibodies which is made of Protein (RER is involved) and GB helps in secreting out those produced antibodies.

Topic: Biology, Human Health and Diseases, NEET
A student measures the terminal potential difference (V) of a cell (of emf $\varepsilon$ and internal resistance $r$ ) as a function of the current (I) flowing through it. The slope and intercept of the graph between $V$ and $I$, then respectively, equal

Options:
A $\varepsilon$ and $-r$
B $-\mathrm{r}$ and $\varepsilon$
C $r$ and $-\varepsilon$
D $-\varepsilon$ and $r$

The correct answer is:
$-\mathrm{r}$ and $\varepsilon$

Solution:
According to Ohm's law
$$
\frac{\mathrm{dV}}{\mathrm{dI}}=-\mathrm{r}
$$
and $V=\varepsilon$ if $I=0$
[As $\mathrm{V}+\mathrm{Ir}=\varepsilon$ ]
$\therefore$ Slope of the graph $=-r$ and intercept $=\varepsilon$

Topic: Physics, Current Electricity, NEET, NEET 2009 (Screening)
A student plots a graph between the inverse of magnification 1m produced by a thin convex lens and the object position u as shown in the figure. The focal length of the lens used, was

Options:
A bca
B bca
C cb
D bc

The correct answer is:
cb

Solution:
1v-1u=1f
uv-1=uf
uv=uf+1
1m=uf+1
slope=1f
1f=bc
f=cb

Topic: Physics, Ray Optics, NEET
A student was given a sample of tissue. He observes and concludes the following characters.

(i) The cells are composed of a single layer of tall and slender cells.

(ii) Their nuclei are located at the base.

(iii) Free surface may have microvilli.

(iv) It is found in the lining of stomach and intestine.

(v) It helps in secretion and absorption.

Based on the above features identify the epithelium.

Options:
A Cuboidal epithelium
B Columnar epithelium
C Squamous epithelium
D Keratinized epithelium

The correct answer is:
Columnar epithelium

Solution:
The epithelium is a protective tissue of animals. It is divided into simple and compound epithelium on the basis of layers resting on the basement membrane. The simple epithelium consists of only one layer. This epithelium is further divided into various types depending on the shape of cells. These are squamous epithelium, cuboidal epithelium, columnar epithelium, ciliated epithelium and pseudostratified epithelium. Columnar epithelium consists of tall or pillar like cells in which length is more than the width and so nuclei appear to be located at the base of cells. This epithelium causes absorption and secretion and to increase the surface area this epithelium also shows the presence of microvilli. This is known as brush bordered epithelium. The columnar epithelium is found in the lining of stomach and intestine.

Topic: Biology, Structural Organisation in Animals, NEET
A student wishes to study the cell structure under a light microscope having $10 \mathrm{X}$ eyepiece and $45 \mathrm{X}$ objective. He should illuminate the object by which one of the following colours of light so as to get the best possible resolution?

Options:
A blue
B green
C yellow
D red

The correct answer is:
blue

Solution:
In order to increase the resolution, the specimen must be viewed using either shorter wavelength $(\lambda)$ light or through an imaging medium with a relatively high refractive index or with optical components which have a high numerical aperture (NA). thus, resolution of microscope in inversely proportional to the wavelength of the light used.
$$
\Delta d=\frac{\lambda}{2 n \sin \theta}
$$
Where,
$$
\begin{aligned}
& \lambda=\text { wavelength } \\
& n=\text { refractive index } \\
& \theta=\text { half angle subtended } \\
& \Delta d=\text { shortest distance. }
\end{aligned}
$$

Topic: Biology, Cell - The Unit of Life, NEET, NEET 2005
A submarine A travelling at 18km hr-1 is being chased along the line of its velocity by another submarine B travelling at 27 km hr-1 . B sends a sonar signal of 500 Hz to detect A and receives a reflected sound of frequency v. The value of v is closed to (Speed of sound in water 1500 m s-1 )

Options:
A 504Â Hz
B 499Â Hz
C 502 Hz
D 507Â Hz

The correct answer is:
502 Hz

Solution:
VA=18 km h-1=5 m s-1 ; VB=27 km h-1=7.5m s-1
Frequency received by A, fA=f01500-51500-7.5
Frequency of reflected wave as heard by B.
f'B=fA1500+7.51500+5
=f01500-51500-7.51500+7.51500+5
=50014951492.51507.51505
=501.67 Hz≈502 Hz

Topic: Physics, Waves and Sound, NEET
A substance of mass 4.953 g occupies 1.5â cm 3 of volume. The density of the substance (in gâ cm â3 ) with correct number of significant figures is

Options:
A 3.3
B 3.300
C 3.302
D 33.0

The correct answer is:
3.3

Solution:
Mass of the substance m=49.53 g
Volume V=1.5 cm3
We know that,
d=mV
d=4.9531.5
d=3.302
d=3.3

Topic: Physics, Units and Dimensions, NEET
A substance undergoes first order decomposition involving two parallel first order reactions as :

k1=1.25 Ã 10-4 s-1

k2=3.80 Ã 10-5 s-1

The mole percentage of B in the products is :

Options:
A 23.17
B 77
C 30.16
D 69.84

The correct answer is:
77

Solution:
mole % of B=12.5Ã10-512.5+3.8Ã10-5Ã 100=12.516.3Ã100
=76.68 %

Topic: Chemistry, Chemical Kinetics, NEET
A sugary solution is changed to vinegar by the action of

Options:
A Azotobacter
B Acetobacter aceti
C Bacillus subtilis
D Mycoderma aceti

The correct answer is:
Acetobacter aceti

Solution:
During the production of vinegar, sugar is first fermented to alcohol and the alcohol is fermented further to acetic acid. Acetobacter aceti is used for the preparation of vinegar from the fermented sugar solution.

Topic: Biology, Microbes in Human Welfare, NEET
A swimmer coming out from a pool is covered with a film of water weighing about 18g. How much heat must be supplied to evaporate this water at 298 K? Also calculate the internal energy of vaporisation at 298K. (∆vapH⊖for water at 298K= 44.01kJ mol–1)

Options:
A Heat supplied is 56.47 kJ and ∆vapUvis 50.03 kJ
B Heat supplied is 48.53 kJ and ∆vapUvis 44.01 kJ
C Heat supplied is 50.03 kJ and ∆vapUvis 56.47 kJ
D Heat supplied is 44.01 kJ and ∆vapUvis 41.53 kJ

The correct answer is:
Heat supplied is 44.01 kJ and ∆vapUvis 41.53 kJ

Solution:
Correct Option is : (D)
Heat supplied is 44.01 kJ and ∆vapUvis 41.53 kJ

Topic: Chemistry, Thermodynamics (C), NEET
A symmetrical uniform solid cube of side 5 m is placed on a horizontal surface beside a vertical wall, one side of the cube is making an angle 45Â° with the floor as shown. If coefficient of friction Î¼ is the same for both wall and floor, the minimum value of Î¼ so that cube does not slip

Options:
A μ = 1
B Î¼ = 0
C μ = 1 3
D Impossible to balance for any value of μ

The correct answer is:
μ = 0

Solution:
At angle 45Â°, N and Mg balance each other, they both pass through centre of mass, so no need for friction to balance it

Topic: Physics, Laws of Motion, NEET
A symmetrical uniform solid cube of the side 5 m is placed on a horizontal surface beside a vertical wall, one side of the cube is making an angle 45Â° with the floor as shown. If the coefficient of friction Î¼ is the same for both wall and floor, the minimum value of Î¼ so that cube does not slip is

Options:
A μ = 1
B Î¼ = 0
C μ = 1 3
D Impossible to balance for any value of μ

The correct answer is:
μ = 0

Solution:
At an angle 45Â°, N and Mg balance each other. As they both pass through the centre of mass, so no need for friction to balance it

Topic: Physics, Laws of Motion, NEET
A syndrome is characterized by the furrowed tongue, characteristic palm crease, mental retardation and short-statured with a small round head. It is due to the anomaly of which of the following chromosome?

Options:
A X
B Y
C 18th
D 21st

The correct answer is:
21st

Solution:
Down's syndrome is chromosomal disorder. The cause of this genetic disorder is the presence of an additional copy of the chromosome number 21 (trisomy of 21). This disorder was first described by Langdon Down.

Topic: Biology, Principles of Inheritance and Variation, NEET
A system consists of four equal charges -Q placed at the four corners of a square and another charge q is placed at the centre of the square, then the value of q for which the system is in equilibrium, is

Options:
A -Q4(1+22)
B Q2(1+22)
C -Q2(1+22)
D Q41+22

The correct answer is:
Q41+22

Solution:
If the system is in equilibrium then the potential energy of the system will be zero

42×2Q24πε0a+Q24πε02a-4×14πε0 Qq a2=0

⇒q=Q41+22

Topic: Physics, Electrostatics, NEET