datavorous/entrance-exam-dataset huggingface dataset:
The relation between n1 and n2 if the behavior of light ray is as shown in the figure

Options:
A n2>n1
B n1≫n2
C n1>n2
D n1=n2

The correct answer is:
n2>n1

Solution:
When convex lens is surrounded by denser medium, it behaves like a diverging lens

Topic: Physics, Ray Optics, NEET
The relation between nm (nm=the number of permissible values of magnetic quantum number (m)) for a given value of azimuthal quantum number l, is

Options:
A nm=l+2
B l=nm-12
C l=2nm+1
D nm=2l2+1

The correct answer is:
l=nm-12

Solution:
The possible magnetic quantum number values for a given value of azimuthal quantum number l are -l to +l through 0. Suppose if l=1, the possible nm values are -1,0,+1. The mathematical formula can be written as follows,

nm=2l+1⇒l=nm-12

Topic: Chemistry, Structure of Atom, NEET, NEET 2023 (All India)
The relation between pressure exerted by an ideal gas (pideal) and observed pressure (preal) is given by the equation
If pressure is taken in Nm–2, number of moles in mol and volume in m3, Calculate the unit of ‘a’.

Options:
A Nm3mol–2
B Nm4mol–1
C Nm4mol–2
D Nm3mol–1

The correct answer is:
Nm4mol–2

Solution:
Correct Option is : (C)
Nm4mol–2

Topic: Chemistry, States of Matter, NEET
The relation between S (solubility) and Ksp (solubility product) for a sparingly soluble binary electrolyte

Options:
A S=Ksp2
B S=Ksp
C S=Ksp
D S=12Ksp

The correct answer is:
S=Ksp

Solution:
For a binary electrolyte,
Ksp=S×S=S2
S=Ksp .

Topic: Chemistry, Ionic Equilibrium, NEET
The relation between species richness and area for a wide variety of taxa (angiosperm plants, birds, bats, freshwater fishes) is a

Options:
A Parabola
B Rectangular hyperbola
C Ellipse
D Straight line

The correct answer is:
Rectangular hyperbola

Solution:
While exploring South American jungles, German naturalist Alexander von Humboldt found that within a region, richness of species increases with an increase in the explored area, but only to a limit. When a graph with species richness on Y-axis and area on X-axis is plotted, it resembles a rectangular hyperbola, with the equation S = CAz, where 'S' is species richness, 'A' is an area, 'C' is Y-intercept and 'z' is the regression co-efficient.

Topic: Biology, Biodiversity and its Conservation, NEET
The relation between time t and distance x is t=ax2+bx where a and b are constants. The acceleration is

Options:
A −2abv2
B 2bv3
C −2av3
D 2av2

The correct answer is:
−2av3

Solution:
t=ax2+bx

dtdx=2ax+b

or dxdt=(2ax+b)−1

or v=(2ax+b)−1

Acceleration=dvdt

=dvdx·dxdt

=(−1)(2ax+b)−2(2a)(2ax+b)−1

=−2a(2ax+b)−3=−2av3

Topic: Physics, Motion In One Dimension, NEET
The relations amongst the three elements earth's magnetic field, namely horizontal component $\mathrm{H}$, vertical component $\mathrm{V}$ and dip $\delta$ are, $\left(\mathrm{B}_{\mathrm{E}}=\right.$ total magnetic field $)$

Options:
A $V=B_E \tan \delta, H=B_E$
B $V=B_E \sin \delta, H=B_E \cos \delta$
C $V=B_E \cos \delta, H=B_E \sin \delta$
D $V=B_E, H=B e_E \tan \delta$

The correct answer is:
$V=B_E \sin \delta, H=B_E \cos \delta$

Solution:
Let $\mathrm{B}_{\mathrm{E}}$ be the net magnetic field at same point. $\mathrm{H}$ and $\mathrm{V}$ be the horizontal and vertical components of $\mathrm{B}_{\mathrm{E}}$. Let $\delta$ be the angle of dip, which is the angle between direction of earth's magnetic field $B_E$ and horizontal line in the magnetic meridian.
Thus, from figure, we can see that
$$
\mathrm{H}=\mathrm{B}_{\mathrm{E}} \cos \delta \text { and } \mathrm{V}=\mathrm{B}_{\mathrm{E}} \sin \delta
$$

Topic: Physics, Magnetic Properties of Matter, NEET, NEET 2019 (Odisha)
The relationship between CoNH34Cl2NO2 and CoNH34Cl.NO2Cl isomers is

Options:
A Linkage
B Geometrical
C Ionization
D Optical

The correct answer is:
Ionization

Solution:
Both produce different ions in solution state-
Co NH 3 ) 4 Cl 2 NO 2 → Co ( NH 3 ) 4 Cl 2 ] + +NO 2 −
Co ( NH 3 ) 4 Cl⋅  NO 2 Cl→ Co ( NH 3 ) 4 Cl⋅ NO 2   + + Cl −

Topic: Chemistry, Coordination Compounds, NEET
The relationship between energy (E) of wavelengths 2000 A0 and 8000 A0, respectively is

Options:
A E1=4E2
B E1=2E2
C E1=E22
D E1=E24

The correct answer is:
E1=4E2

Solution:
According to Planck's theory. E=hcλ,
i.e., E1E2=λ2λ1 ∵E∝1λ
Thus, E1E2=80002000=4
∴ E1=4 E2

Topic: Chemistry, Structure of Atom, NEET
The relationship between K p and K c is K p â=â K c (RT) În . What would be the value of În for the reaction:

NH 4 Cl(s)â NH 3 (g)â+âHCl(g) ?

Options:
A 1
B 0.5
C 1.5
D 2

The correct answer is:
2

Solution:
The relationship between K p and K c is given as ⇒ K p  =  K c (RT) Δn .
When, Δn = moles of gaseous species and Δn = (moles of product) - (moles of reactant) For the reaction, NH 4 Cl(s)→ NH 3 (g) + HCl(g)
we have 2 moles of gaseous species in the product side and none in the reactant side.
∴Δn = 2−0 = 2
Hence, 2 is the correct option

Topic: Chemistry, Chemical Equilibrium, NEET
The relationship between the force F and position x of a body is as shown in the figure. The work done in displacing the body from x=1 m to x=5 m will be-

Options:
A 30Â J
B 15 J
C 25Â J
D 20Â J

The correct answer is:
15 J

Solution:
In F- x graph, the total area under the curve gives total work done. To calculate the total area.
Area =10+5-5+5=15 J

Topic: Physics, Work Power Energy, NEET
The relative error in the determination of the surface area of a sphere is α . The relative error in the determination of its volume is

Options:
A 32α
B 23α
C α
D 52α

The correct answer is:
32α

Solution:
Δss=2×Δrr
ΔVV=3×Δrr
∴    Δv v   =   3 2    Δs s      Δv v   =   3 2  α

Topic: Physics, Units and Dimensions, NEET
The relative lowering of vapour pressure caused by dissolving 71.3 g of a substance in 1000 g of water is 7.13×10-3 . The molecular mass of the substance is (consider the solution is highly diluted)

Options:
A 180 g/mol
B 18 g/mol
C 1.8 gâ/mol
D 360 gâ/mol

The correct answer is:
180 g/mol

Solution:
ÎPP0=XB
ÎPP0ânBnA=wBÃmAmBÃwA
7.13Ã10-3=71.3Ã18mBÃ1000
mB=180 g/mol .

Topic: Chemistry, Solutions, NEET
The relative lowering of vapour pressure of an aqueous solution containing non-volatile solute is 0.0125. The molality of the solution is

Options:
A 0.70 m
B 0.50 m
C 0.80 m
D 0.40 m

The correct answer is:
0.70 m

Solution:
As we know
po-ppo=x1= mole fraction of solute
The ratio po-ppo is the relative lowering of vapour pressure, which is equal to 0.0125 here.
So X1=0.0125
The relation between the mole fraction and molality is
1X1-1=1000m×18 (molecular weight of H2O=18 )
or 10.0125-1=100m×18 w
m=0.70 m

Topic: Chemistry, Solutions, NEET
The relative reactivities of acyl compounds towards nucleophilic substitution are in the order of

Options:
A Acyl chloride $>$ Acid anhydride $>$ Ester $>$ Amide
B Ester $>$ Acyl chloride $>$ Amide $>$ Acid anhydride
C Acid anhydride $>$ Amide $>$ Ester $>$ Acyl chloride
D Acyl chloride $>$ Ester $>$ Acid anhydride $>$ Amide

The correct answer is:
Acyl chloride $>$ Acid anhydride $>$ Ester $>$ Amide

Solution:
Key Idea : The ease of nucleophilic substitution is depend upon the nature of leaving group. When the leaving tendency of a group in a compound is high, then the compound is more reactive towards nucleophilic substitution.
The nucleophilic acyl substitution is completed in two steps as shown below
The reactivity of the compound may be explained on the basicity of the leaving group. A weaker base is a better leaving group. The basicity order is as :
$$
\mathrm{Cl}^{-}>\mathrm{RCOO}^{-}>\mathrm{RO}^{-}>\mathrm{NH}_2^{-}
$$
Hence, the order of leaving tendency is
$$
\mathrm{Cl}^{-}>\mathrm{RCOO}^{-}>\mathrm{R}-\mathrm{O}^{-}>\mathrm{NH}_2^{-}
$$
and therefore, the order of reactivity of acyl compound is as :
Acyl chloride $>$ Acid anhydride $>$ Ester $>$ Amide

Topic: Chemistry, Electrochemistry, NEET, NEET 2008 (Screening)
The relative reactivity of 1°, 2°, 3° hydrogen’s towards chlorination is 1: 3.8 :5. Calculate the percentages of all monochlorinated products obtained from 2-methylbutane.

Options:
A 1° monochlorinated product = 41.7% , 2° monochlorinated product = 35.2% and 3° monochlorinated product = 47.1%
B 1° monochlorinated product = 41.7% , 2° monochlorinated product = 39.2% and 3° monochlorinated product = 23.1%
C 1° monochlorinated product = 41.7% , 2° monochlorinated product = 35.2% and 3° monochlorinated product = 23.1%
D 1° monochlorinated product = 85.7% , 2° monochlorinated product = 35.2% and 3° monochlorinated product = 23.1%

The correct answer is:
1° monochlorinated product = 41.7% , 2° monochlorinated product = 35.2% and 3° monochlorinated product = 23.1%

Solution:
Correct Option is : (C)
1° monochlorinated product = 41.7% , 2° monochlorinated product = 35.2% and 3° monochlorinated product = 23.1%

Topic: Chemistry, Hydrocarbons, NEET
The relative strength of interionic/intermolecular forces in decreasing order is

Options:
A ion-dipole > dipole-dipole > ion-ion
B dipole-dipole > ion-dipole > ion-ion
C ion-ion > ion-dipole > dipole-dipole
D ion-dipole > ion-ion > dipole-dipole

The correct answer is:
ion-ion > ion-dipole > dipole-dipole

Solution:
Interionic/intermolecular forces ∝ charge present on species
As ions are charged while dipole is only partially charged so the relative strength of interionic/intermolecular forces in decreasing order is
ion-ion > ion-dipole > dipole-dipole

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
The ___________ relays impulses from the CNS to skeletal muscles.

Options:
A somatic neural system
B autonomic neural system
C the central neural system
D the vertebral system

The correct answer is:
somatic neural system

Solution:
The nervous system is divided into central and peripheral nervous systems. The PNS is divided into two divisions called somatic neural system and autonomic neural system. The somatic neural system relays impulses from the CNS to skeletal muscles while the autonomic neural system transmits impulses from the CNS to the involuntary organs and smooth muscles of the body.

Topic: Biology, Neural Control and Coordination, NEET
The releasing hormones are secreted by

Options:
A thymus
B pituitary
C hypothalamus
D pancreas

The correct answer is:
hypothalamus

Solution:
Hypothalamus is a master of master endocrine gland i.e. the pituitary gland. All the hormonal secretion from the pituitary are directly or indirectly under the influence of hypothalamus. This is connected to the pituitary via stalk known as infundibulum. The pituitary gland consists of two parts: adenohypophysis and neurohypophysis. Adenohypophysis releases many hormones like GH, TSH, ACTH, PRL, FSH, LH etc. These are released under the influence of releasing and inhibiting hormones of hypothalamus. These hormones reach the pituitary through hypothalami-hypophyseal portal system. Example : Thyroid-stimulating hormone (TSH) is released when thyroid releasing hormone (TRH) is released from hypothalamus.

Topic: Biology, Chemical Coordination and Integration, NEET
The removal of stamens from bisexual flowers before the maturation of the anther in order to avoid self-pollination in the flowers is called ___.

Options:
A Emasculation
B bagging
C dehiscence
D none of the above

The correct answer is:
Emasculation

Solution:
Emasculation is the removal of stamens from bisexual flowers before the maturation of the anther in order to avoid self-pollination in the flowers

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
The renin–angiotensin mechanism to increase blood pressure involves organs in the following order:

Options:
A Kidney - Liver - Lungs - Adrenal gland - Kidney
B Kidney - Lungs - Liver - Adrenal gland - Kidney
C Kidney - Liver - Adrenal gland - Lungs - Kidney
D Kidney - Lungs - Adrenal gland - Liver - Kidney

The correct answer is:
Kidney - Liver - Lungs - Adrenal gland - Kidney

Solution:
In response to a decrease in blood pressure or GFR, the kidneys release renin. Renin acts on the liver and converts angiotensinogen into angiotensin I. In the lungs, angiotensin I is converted to angiotensin II with the help of an angiotensin-converting enzyme. Angiotensin II is a vasoconstrictor and also stimulates the adrenal gland which releases aldosterone. Aldosterone acts on the kidneys and helps in the absorption of sodium ions. Thus, this mechanism increases blood pressure.

Topic: Biology, Excretory Products and their Elimination, NEET
The repressor of the lac operon is synthesised all the time constitutively from the

Options:
A p gene.
B i gene.
C z gene.
D o gene.

The correct answer is:
i gene.

Solution:
Lac operon is regulated by repressor protein which is synthesized by regulator gene also called as inhibitor gene (i - gene). This active regulator protein binds to the operator and turns the system off, thus structural gene cannot syntheses mRNA and thus enzymes.

Topic: Biology, Molecular Basis of Inheritance, NEET
The Reproductive and Child Health Care programme (RCH) in India were initiated in

Options:
A 1951
B 1971
C 2000
D 2003

The correct answer is:
1951

Solution:
India was the first country in the world to initiate the 'Family Planning' programme in 1951 at national level. These programmes were popularly named as Reproductive and Child Health Care (RCH) programmes, which creates awareness among people to build up a reproductively healthy society.

Topic: Biology, Reproductive Health, NEET
The RER is the cell synthesized protein which would be later used in building the plasma membrane. However, it is observed that the protein in the membrane is slightly different from the protein made in the RER. The protein was probably modified in another cell organelle. Identify the organelle in the given diagram.

Options:
A D
B A
C B
D C

The correct answer is:
D

Solution:
The plasma membrane consists of glycoproteins. In golgi bodies, glycosylation of proteins takes place, i. e., the addition of carbohydrates to produce glycoproteins.

Topic: Biology, Cell - The Unit of Life, NEET
The residual persistent part which forms the perisperm in the seeds of beet is :

Options:
A Calyx
B Endosperm
C Nucellus
D Integument

The correct answer is:
Nucellus

Solution:
Persistent nucellus in beet and pepper in called Perisperm. Nucellus is diploid sporogenous tissue which is generally degraded, but present in above mentioned seeds.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET, NEET 2022 (Phase 2)
The residue left after methane production from cattle dung is

Options:
A Burnt
B Buried in landfills
C Used as manure
D Used in civil construction

The correct answer is:
Used as manure

Solution:
Thus gobar (excreta/dung) of cattle is rich in these bacteria. Dung can be used for generation of biogas, commonly called gobar gas. The residue left after methane production from cattle dung is used as manure.

Topic: Biology, Microbes in Human Welfare, NEET
The resistance in the two arms of the meter bridge are 5 Ω and RΩ, respectively. When the resistance R is shunted with an equal resistance, the new balance point is at 1.6l1. The resistance ‘ R ’ is:

Options:
A 10Â Î©
B 15 Î©
C 20Â Î©
D 25Â Î©

The correct answer is:
15 Î©

Solution:
The resistance of meter bridge is directly proportional to the length of the bridge wire.

5R=l1100-l1
5R/2=1.6l1100-1.6l1
Solving l1=25 cm and R=15 Ω

Topic: Physics, Current Electricity, NEET, NEET 2014
The resistance of 0.01 N NaCl solution at 25°C is 200 ohm. Cell constant of the conductivity cell is unity. The equivalent conductivity of the solution is

Options:
A 500 ohm-1cm2eq-1
B 5 ohm-1cm2eq-1
C 250 ohm-1cm2eq-1
D None

The correct answer is:
500 ohm-1cm2eq-1

Solution:
K=1RÃ cell constant
Here K = specific conductance
=1200Ã1=5Ã10-3 ohm-1cm-1
Î»v=KÃVN
=5Ã10-3Ã100Ã1000
500 ohm-1cm2eq-1

Topic: Chemistry, Electrochemistry, NEET
The resistance of 1N solution of acetic acid is 250âohm , when measured in a cell having a cell constant of 1.15 cm-1. The equivalent conduction ( in Î© -1 cm 2 eq -1 ) of 1N acetic acid is .......

Options:
A 18.4
B 9.2
C 4.6
D 2.3

The correct answer is:
4.6

Solution:
K=CÃcell constant
=Cell constantR=1.15250
â§eq=KÃ1000Normality=1.15250Ã10001
=4.6 Î©-1cm2eq-1.

Topic: Chemistry, Electrochemistry, NEET
The resistance of a conductivity cell containing 0.001M KCl solution at 298 K is 1500 Ω. What is the cell constant if conductivity of 0.001M KCl solution at 298 K is 0.146 × 10–3 S cm–1.

Options:
A 1.46 cm⁻¹
B 0.15 cm⁻¹
C 1460 cm⁻¹
D 0.00146 cm⁻¹

The correct answer is:
0.15 cm⁻¹

Solution:
Correct Option is : (B)
0.15 cm⁻¹

Topic: Chemistry, Electrochemistry, NEET
The resistance of a germanium junction diode, whose V-I characteristics is shown in the figure, will be vk=0.3 V.

Options:
A 5 kΩ
B 0.2 kΩ
C 2.3 kΩ
D 102.3 kΩ

The correct answer is:
0.2 kΩ

Solution:
R=ÎVÎI=2.3-0.310Ã10-3
R=210Ã103
R=0.2Ã103 Î©
=0.2 kΩ

Topic: Physics, Semiconductors, NEET
The resistance of a metal increases with an increase in temperature, because

Options:
A the collisions of the conducting electrons with the electrons increases
B the collisions of the conducting electrons with the lattice consisting of the ions of the metal increases
C the number of conduction electrons decreases
D the number of conduction electrons increases

The correct answer is:
the collisions of the conducting electrons with the lattice consisting of the ions of the metal increases

Solution:
The resistance of a metal increases with an increase in the temperature, because with an increase in temperature, the ions of the conductor vibrate with greater amplitude and the collision between ions and electrons becomes more frequent.

Topic: Physics, Current Electricity, NEET
The resistance of a moving coil galvanometer is 20 Ω. It requires 0.01A current for full-scale deflection. The value of resistance to convert it into a voltmeter of the range 20 V will be

Options:
A 198Â Î©
B 1980 Î©
C 20Â Î©
D 0Â Î©

The correct answer is:
1980 Î©

Solution:
VG=IGG
VG=0.01Ã20=0.2 V
R=VVG-1G
R=200.2-120=1980 Î©

Topic: Physics, Current Electricity, NEET
The resistance of a straight conductor does not depend on its

Options:
A length
B temperature
C material
D shape of cross-section

The correct answer is:
shape of cross-section

Solution:
Resistance of a conductor
R=ÏlA ...(i)
As Ï depends on the material,
so R depends on the material.
According to the given formula in Eq.(i), it depends on length. Moreover resistance âtemperature.
If R0= resistance of conductor at 0Â° C,
Rt= resistance of conductor at tÂ°C,
and a,Î²= temperature coefficient of resistance, then
Rt=R01+Î±t+Î²t2
The resistance of a straight conductor does not depend on shape of cross-section.

Topic: Physics, Current Electricity, NEET
The resistance of a wire is R ohm. If it is melted and stretched to n times its original length, its new resistance will be

Options:
A Rn
B n2R
C Rn2
D nR

The correct answer is:
n2R

Solution:
We know that, R = ρ l A
Or R=ρl2Volume ⇒R∝ l 2
According to question l 2 =n l 1
R 2 R 1 = n 2 l 1 2 l 1 2 or, R 2 R 1 = n 2 ⇒ R 2 = n 2 R 1
as R 1 =R
New resistance ( R 2 )= n 2 R

Topic: Physics, Current Electricity, NEET
The resistance of a wire is R Î©.The wire is stretched to double its length keeping volume constant. Now the resistance of the wire will become

Options:
A 4R Î©
B 2R Î©
C 1R Î©
D 1 2 R Î©

The correct answer is:
4R Î©

Solution:
When wire is stretched to doubled its length, its resistance becomes four times
R=ρlA×ll=ρl2V
R∝l2 so R1R2=l12l22
RR2=l2l2
R2=4R

Topic: Physics, Current Electricity, NEET
The resistance of an ammeter is $13 \Omega$ and its scale is graduated for a current upto 100 amps. After an additional shunt has been connected to this ammeter it becomes possible to measure currents upto 750 amperes by this meter. The value of shunt-resistance is:

Options:
A $2 \Omega$
B $0.2 \Omega$
C $2 \mathrm{k} \Omega$
D $20 \Omega$

The correct answer is:
$2 \Omega$

Solution:
Let the shunt resistance be S.

\(\begin{aligned} & \text {Given: } I=750 \mathrm{~A}, \\ & I_g=100 \mathrm{~A}, R_G=13 \Omega \\ & \text {From the figure, } \\ & I_g R_G=\left(I-I_g\right) S \\ & \text {or } 100 \times 13=[750-100] S \\ & \text {or } 1300=650 \mathrm{~S} \\ & \therefore \quad S=1300 / 650=2 \Omega .\end{aligned}\)

Topic: Physics, Current Electricity, NEET, NEET 2007
The resistance of an ammeter is 13 Î© and its scale is graduated for current up to 100 A. After an additional shunt has been connected to this ammeter it becomes possible to measure currents up to 750 A by this meter. The value of shunt resistance is

Options:
A 0.2 Ω
B 2 kΩ
C 20 Ω
D 2 Ω

The correct answer is:
2 Ω

Solution:
We know,
IIS=1+GS
750100=1+13S
S=2 Ω

Topic: Physics, Current Electricity, NEET
The resistance of metal sheet 1 between A and B is R1 and the resistance of sheet 2 between A' and B' is R2. The value of the ratio R1R2 is

Options:
A 1
B 12
C 2
D 4

The correct answer is:
1

Solution:
For Sheet 1 resistance is,
R1=Ïllt=Ït
For Sheet 2 resistance is,
R2=Ï2l2lÃt=Ït
â´ R1R2=1

Topic: Physics, Current Electricity, NEET
The resistance of metal sheet 1 between the shaded portion is R1 and Resistance between shaded portion for sheet 2 is R2 the R1/R2 is

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

The correct answer is:
1

Solution:
Resistance = Resistivity×Length between two faces Area of the face
R1=ρllt=ρt R2=ρ2l2l×t =ρt
∴ R1/R2=1

Topic: Physics, Current Electricity, NEET
The resistance of platinum wire at 0 °C is 2 Ω and 6.8 Ω at 80 °C. The temperature coefficient of resistance of the wire is:

Options:
A 3×10-1 °C-1
B 3×10-4 °C-1
C 3×10-3 °C-1
D 3×10-2 °C-1

The correct answer is:
3×10-2 °C-1

Solution:
The variation of resistance of a conducting metal with temperature is given by

RT=R01+αT2-T1 ...1

Substitute the values of the known parameters into equation (1) and solve to calculate the required temperature coefficient.

6.8 Ω=2 Ω×1+α80-0° C⇒1+80α=3.4⇒80α=2.4⇒α=3×10-2 C-1

Topic: Physics, Current Electricity, NEET, NEET 2023 (All India)
The resistance of the following circuit figure between A and B is

Options:
A 32 Ω
B 2 Ω
C 4 Ω
D 8Â Î©

The correct answer is:
32 Ω

Solution:
Since resistance connected in arms CE, ED, CF
and FD will form a balanced Wheatstone bridge,
therefore, the resistance of arm EF becomes
ineffective. Now resistance of arm CED or CFD=2+2=4Î©
Effective resistance of these two parallel arm =4Ã44+4=2Î©
Now resistance of arm ACDB=2+2+2=6Î©
in parallel with resistance arm AB=2Î© Thus,
effective resistance between A and B
=6Ã26+2=32Î©

Topic: Physics, Current Electricity, NEET
The resistance R=VI, where V=(100Â±5) V and I=10Â±0.2 A. The maximum percentage error in R is

Options:
A 5.2%
B 4.8%
C 7%
D 3%

The correct answer is:
7%

Solution:
Given, V=100±5 V ⇒ ∆V=5 V
I=10±0.2 A ⇒ ∆I=0.2 A
R=VI
∆RR=∆VV+∆II
=5100+0.210=0.05+0.02
=0.07
=7%

Topic: Physics, Units and Dimensions, NEET
The resistances of the four arms $P, Q, R$ and $S$ in a Wheatstone's bridge are $10 \Omega, 30 \Omega, 30 \Omega$ and $90 \Omega$, respectively. The emf and internal resistance of the cell are $7 \mathrm{~V}$ and $5 \Omega$ respectively. If the galvanometer resistance is $50 \Omega$, the current drawn from the cell will be

Options:
A $1.0 \mathrm{~A}$
B $0.2 \mathrm{~A}$
C $0.1 \mathrm{~A}$
D $2.0 \mathrm{~A}$

The correct answer is:
$0.2 \mathrm{~A}$

Solution:
Effective resistance,
$R_{\text {eff }}=\frac{40 \times 120}{120+40}=\frac{4800}{160}=30 \Omega$
$\therefore$ Current $=\frac{7}{(30+5)}=\frac{7}{35}=0.2 \mathrm{~A}$
$\left[\because i=\frac{E}{R+r}\right]$

Topic: Physics, Current Electricity, NEET, NEET 2013 (All India)
The resistivity of potentiometer wire is 40Ã10-8 Î© m and its area of cross-section is 8Ã10-6 m2. If 0.2 A current is flowing through the wire, the potential gradient of the wire is

Options:
A 0.1 V m-1

B 10-2 V m-1
C 10-3 V m-1
D 10-4 V m-1

The correct answer is:
10-2 V m-1

Solution:
R=ρlA
∴ Rl=ρA=40×10-88×10-6=5×10-2
Vl=IRl=0.2×5×10-2=10-2 V m-1

Topic: Physics, Current Electricity, NEET