datavorous/entrance-exam-dataset huggingface dataset:
A ray of light, travelling in medium A, is incident on the plane interface of two medium A and B and gets refracted into the medium B. The angle of incidence is i and that of refraction is r. The graph between sin(i) and sin(r) is as shown in the diagram. The correct statement among the following is

Options:
A Speed of light in medium B is three fourth of that in medium A
B Total internal reflection can take place
C Refraction index of medium A is greater than that of medium B
D None of these

The correct answer is:
Speed of light in medium B is three fourth of that in medium A

Solution:
sin i sin r = cot 3 7 = 4 3 = V A V B
as going from rarer to denser no TIR can take place
μ B μ A > 1 ⇒ μ B > μ A

Topic: Physics, Ray Optics, NEET
A ray of light, travelling in the direction 12i^+3 j^, is incident on a plane mirror. After reflection, it travels along the direction 12i^-3 j^. The angle of incidence is

Options:
A 30Â°
B 45°
C 60°
D 75°

The correct answer is:
30°

Solution:
Î± = angle between vectors
cosÎ±=12 i^+3 j^Â·12 i^-3 j^i^+3 j^i^-3 j^
= 1 4 1 - 3 1 Ã 1 = - 2 4 = - 1 2
Î±=120Â°=2Ï3
â´ Ï=Î±=2Î¸
Ï = 2 Ï 3 = 2 Î¸
Î¸=Ï3Ã2=Ï6=30Â°

Topic: Physics, Ray Optics, NEET
A ray of light travelling through rarer medium is incident at very small angle i on a glass slab and after refraction its velocity is reduced by 20%. The angle of deviation is

Options:
A i8
B i5
C i2
D 4i5

The correct answer is:
i5

Solution:
As at interface, velocity of light reduces by 20% of C
â´ Î´=20% i=20100Ãi=i5

Topic: Physics, Ray Optics, NEET
A ray of light when incident upon a prism suffers a minimum deviation of 39° . If the shaded half portion of the prism is removed, then the same ray will -

Options:
A suffer a deviation of 19.5°
B suffer a deviation of 39°
C not suffer any deviation
D will be totally internally reflected

The correct answer is:
suffer a deviation of 19.5°

Solution:
δ=μ-1A
δ2δ1=A2A1
δ2δ1=A2A
δ2δ1=12
δ2=δ12
δ2=392
δ2=19.5°

Topic: Physics, Ray Optics, NEET
A reaction, A + B â C + D + q is found to have a positive entropy change. The reaction will be

Options:
A Possible at high temperature.
B Possible only at low temperature.
C Not possible at any temperature.
D Possible at any temperature.

The correct answer is:
Possible at any temperature.

Solution:
Δ G = Δ H - T Δ S
For the given reaction, Δ H = - ve it is exothermic, Δ S = + ve then Δ G = - ve So, the reaction is done will be spontaneous at all temperatures.

Topic: Chemistry, Thermodynamics (C), NEET
A reaction A→B , involves following mechanism
Step 1 A→k1B(fast)
Step 2 B→k2C(slow)
Step 3 C→k3D(fast)
The rate law of the reaction may be given as

Options:
A rate =k1[A]
B rate =k2[B]
C rate =k3[C]
D rate =k1k2k3[B][C]

The correct answer is:
rate =k2[B]

Solution:
As the slowest step is rate determining step.
So rate =k2[B] .

Topic: Chemistry, Chemical Kinetics, NEET
A reaction has ΔH = −33 kJ and ΔS=-58 J/K. This reaction would be

Options:
A Spontaneous at all temperatures
B Non-spontaneous at all temperatures
C Spontaneous above a certain temperature
D Spontaneous below a certain temperature

The correct answer is:
Spontaneous below a certain temperature

Solution:
A reaction is spontaneous only when ΔG is negative
ΔG= ΔH − ve ↓ − TΔS − ve ↓
below T=569 K
ΔG<0

Topic: Chemistry, Thermodynamics (C), NEET
A reaction having equal energies of activation for forward and reverse reaction has

Options:
A ΔS=O
B ΔG=O
C ΔH=0
D All of these

The correct answer is:
ΔH=0

Solution:
ΔH=Ea(F)→Ea(b)
As Ea(F)=Ea(b)
Hence ΔH=0

Topic: Chemistry, Chemical Kinetics, NEET
A reaction having equal energies of activation for forward and reverse reactions has

Options:
A $\Delta S=0$
B $\Delta G=0$
C $\Delta H=0$
D $\Delta H=\Delta G=\Delta S=0$

The correct answer is:
$\Delta H=0$

Solution:
Energy profile diagram for a reaction is as From the figure, it is clear that
So, \(\left(E_2\right)_b=\left(E_2\right)_f+\Delta H\left(\right.\) as, \(\left(E_2\right)_b=\left(E_2\right)_f\)
So, \(\Delta H=0\).
[Here $\left(E_2\right)_b=$ activation energy of backward reaction and $\left(E_2\right)_f=$ activation energy of forward reaction].

Topic: Chemistry, Chemical Kinetics, NEET, NEET 2013 (All India)
A reaction is $50 \%$ complete in 2 hours and $75 \%$ complete in 4 hours. The order of reaction is:

Options:
A 1
B 2
C 3
D 0

The correct answer is:
1

Solution:
A per the data given
$$
t_{75 \%}=2 \times t_{30 \%}
$$
$\therefore$ The order of the reaction is 1 .

Topic: Chemistry, Chemical Kinetics, NEET, NEET 2013 (Karnataka)
A reaction is 50% completed in 2 hours and 75% completed in 4 hours. The order of the reaction is

Options:
A 0
B 1
C 2
D 3

The correct answer is:
1

Solution:
A reaction is 50% completed in 2 hours and 75% completed in 4 hours
t 3/4 =2 t 1/2 for first-order reaction

Topic: Chemistry, Chemical Kinetics, NEET
A reaction is first order in A and second order in B. How is the rate affected on increasing the concentration of B three times?

Options:
A Rate of reaction becomes 6 times
B Rate of reaction becomes 12 times
C Rate of reaction becomes 9 times
D Rate of reaction becomes 4 times

The correct answer is:
Rate of reaction becomes 9 times

Solution:
Correct Option is : (C)
Rate of reaction becomes 9 times

Topic: Chemistry, Chemical Kinetics, NEET
A reaction is first order in A and second order in B. How is the rate affected when the concentrations of both A and B are doubled?

Options:
A Rate of reaction becomes 6 times
B Rate of reaction becomes 8 times
C Rate of reaction becomes 10 times
D Rate of reaction becomes 4 times

The correct answer is:
Rate of reaction becomes 8 times

Solution:
Correct Option is : (B)
Rate of reaction becomes 8 times

Topic: Chemistry, Chemical Kinetics, NEET
A reaction is first order in A and second order in B. Write the differential rate equation.

Options:
A Rate =k[A]2[B]
B Rate =k[A]2[B]2
C Rate =k[A][B]
D Rate =k[A][B]2

The correct answer is:
Rate =k[A][B]2

Solution:
Correct Option is : (D)
Rate =k[A][B]2

Topic: Chemistry, Chemical Kinetics, NEET
A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is (i) doubled (ii) reduced to half ?

Options:
A (i) 2 times (ii) 1⁄4 times
B (i) 1⁄4 times (ii) 4 times
C (i) 4 times (ii) 1⁄4 times
D (i) 4 times (ii) 1⁄2 times

The correct answer is:
(i) 4 times (ii) 1⁄4 times

Solution:
Correct Option is : (C)
(i) 4 times (ii) 1⁄4 times

Topic: Chemistry, Chemical Kinetics, NEET
A reaction proceeds through two paths I and II to convert X→Z.

What is the correct relationship between Q, Q1 and Q2 ?

Options:
A Q=Q1×Q2
B Q=Q1+Q2
C Q=Q2-Q1
D Q=Q1/Q2

The correct answer is:
Q=Q1+Q2

Solution:
As Q is a state function which is independent of path of the reaction so
Q=Q1+Q2

Topic: Chemistry, Thermodynamics (C), NEET
A reaction takes place in three steps with activation energy Ea1=180 kJ/mol, Ea2=80 kJ/mol and Ea3=50 kJ/mol respectively.
Overall rate constant of the reaction is k=k1k2k32/3 .
The activation energy of the reaction will be

Options:
A 140 kJ/mol
B 150 kJ/mol
C 43.44 kJ/mol
D 100 kJ/mol

The correct answer is:
140 kJ/mol

Solution:
The rate of constant of the reaction is
k=k1k2k32/3
Activation energy of the reaction will be
Ea=23[Ea1+Ea2-Ea3]
=23[180+80-50]
=140 kJ/mol.

Topic: Chemistry, Chemical Kinetics, NEET
A reaction X2(g)→Z(g)+12Y(g) exhibits an increase in pressure from 150 mm to 170 mm in 10 minutes. The rate of disappearance of X2 in mm per minute is

Options:
A 2 mm per minute
B 8 mm per minute
C 4 mm per minute
D 6 mm per minute

The correct answer is:
4 mm per minute

Solution:
Total pressure =150-x+x+x2
=150+x2=170
x = 40 mm
Rate of disappearance of X2=4010=4 mm/min.

Topic: Chemistry, Chemical Kinetics, NEET
A reagent which reacts differently with HCHO,  CH 3 CHO and CH 3 COCH 3

Options:
A NH2OH
B NH2NH2
C HCN
D NH3

The correct answer is:
NH3

Solution:
The reagent A, B and C reacts with the carbonyl compounds in the same manner and only NH3 react differently.

Topic: Chemistry, Aldehydes and Ketones, NEET
A real inverted image in a concave mirror is represented by graph ( u,v,f are coordinates)

Options:
A
B
C
D

The correct answer is:

Solution:
For real inverted image formed by concave mirror.
v=âve,âââu=âve,ââf=âve
â u f & v f are positive
So graph show be in 1st qudarant
and 1 v + 1 u = 1 f
â f v + f u = 1
This graph can also be realized by Newtons formula x 1 x 2 = f 2 where x 1 , and x 2 are distance from focus so graph will be rectangular hyperbola
â (1) is right answer.

Topic: Physics, Ray Optics, NEET
A recessive allele is expressed in:

Options:
A Heterozygous condition only
B Homozygous condition only
C Both in homozygous and heterozygous conditions
D Neither in homozygous nor in heterozygous condition

The correct answer is:
Homozygous condition only

Solution:
Recessive allele can express itself only in homozygous condition when two recessive alleles are present. In a dissimilar pair of factor one member of the pair dominates and is called dominant and the other is recessive.

Topic: Biology, Principles of Inheritance and Variation, NEET
A rectangular block of mass $m$ and area of cross-section A floats in a liquid of density $\rho$. If it is given a small vertical displacement from equilibrium it undergoes with a time period $T$, Then:

Options:
A $T \propto \frac{1}{\sqrt{m}}$
B $T \propto \sqrt{\mathrm{A}}$
C $T \propto \frac{1}{\sqrt{A}}$
D $T \propto \frac{1}{\rho}$

The correct answer is:
$T \propto \frac{1}{\sqrt{A}}$

Solution:
Restoring force $=A \times \int g=k x$
$\begin{array}{ll}
\Rightarrow & K=A \rho g \\
\Rightarrow & T=2 \pi \sqrt{\frac{m}{A \rho g}}
\end{array}$
This shows that $T \propto \frac{1}{\sqrt{A}}$.

Topic: Physics, Mechanical Properties of Fluids, NEET, NEET 2006
A rectangular coil of length 0.12 m and width 0.1 m having 50 turns of wire is suspended vertically in a uniform magnetic field of strength 0.2 Weber/m2 . The coil carries a current of 2A . If the plane of the coil is inclined at an angle of 30o with the direction of the field, the torque required to keep coil in stable equilibrium will be:

Options:
A 0.20 Nm
B 0.24Â Nm
C 0.12Â Nm
D 0.15Â Nm

The correct answer is:
0.20 Nm

Solution:
τ→= M→ × B→ =MBsin⁡60o
=Ni ABsin⁡60o
=50 ×2×0.12 ×0.1 ×0.2 × 32
=123 ×10-2 Nm=0.20748 Nm

Topic: Physics, Magnetic Effects of Current, NEET, NEET 2015 (Phase 2)
A rectangular conducting loop consists of two wires on two opposite sides of length l joined together by rods of length d. The wires are each of the same material but with cross-sections differing by a factor of 2. The thicker wire has a resistance R and the rods are of low resistance, which in turn are connected to a constant voltage source V0. The loop is placed in uniform a magnetic field B at 45° to its plane. Find τ, the torque exerted by the magnetic field on the loop about an axis through the centres of rods.

Options:
A $\frac{1}{4\sqrt{2}}\frac{3{{V}_{o}}AB}{R}$
B $\frac{1}{3\sqrt{2}}\frac{{{V}_{o}}AB}{R}$
C $\frac{1}{4\sqrt{2}}\frac{{{V}_{o}}AB}{R}$
D $\frac{1}{2\sqrt{2}}\frac{{{V}_{o}}AB}{R}$

The correct answer is:
$\frac{1}{4\sqrt{2}}\frac{{{V}_{o}}AB}{R}$

Solution:
Correct Option is : (C)
$\frac{1}{4\sqrt{2}}\frac{{{V}_{o}}AB}{R}$

Topic: Chemistry, Magnetic Effects of Current, NEET
A rectangular film of liquid is extended from (4 cmÃ2 cm) to (5 cmÃ4 cm). If the work done is 3Ã10-4 J, the value of the surface tension of the liquid is

Options:
A 0.250 N m-1
B 0.125 N m-1
C 0.2 N m-1
D 8.0 N m-1

The correct answer is:
0.125 N m-1

Solution:
W=2Af-AiT
âT=WAf-AiÃ2
=3Ã10-4 J25Ã4Ã10-4-4Ã2Ã10-4
=0.125 N m-1

Topic: Physics, Mechanical Properties of Fluids, NEET, NEET 2016 (Phase 2)
A rectangular film of liquid is extended from (4 cmÃ2 cm) to (5 cmÃ4 cm). If the work done is 3Ã10-4 J, the value of the surface tension of the liquid is

Options:
A 0.250 N m-1
B 0.125 N m-1
C 0.2 N m-1
D 8.0 N m-1

The correct answer is:
0.125 N m-1

Solution:
W=2Af-AiT
âT=WAf-AiÃ2
=3Ã10-4 J25Ã4Ã10-4-4Ã2Ã10-4
=0.125 N m-1

Topic: Physics, Mechanical Properties of Fluids, NEET
A rectangular loop has a sliding connector PQ of length l and resistance R Î© and it is moving with a speed v as shown. The set-up is placed in a uniform magnetic field going into the plane of the paper. The three currents I1,I2 and I are

Options:
A I1=-I2=BlvR, I=2BlvR
B I1=I2=Blv3R,I=2Blv3R
C I1=I2=I=BlvR
D I1=I2=Blv6R,I=Blv3R

The correct answer is:
I1=I2=Blv3R,I=2Blv3R

Solution:
A moving conductor is equivalent to battery of emf
=vBl (motion emf)
Equivalent circuit
I=I2+I2
Applying Kirchhoff's law
I1R+IR-vBl=0 …(i)
I2R+IR-vBl=0 ...(ii)
Adding Eqs. (i) and (ii), we get
2IR+IR=2vBl
I=2vBl3R
I1=I2=vBl3R

Topic: Physics, Electromagnetic Induction, NEET
A rectangular loop of metallic wire is of length a and breadth b and carries a current i. The magnetic field at the centre of the loop is

Options:
A μ0i4π8a2+b2ab
B μ0i4π4a2+b2ab
C μ0i4π2a2+b2ab
D μ0i4πa2+b2ab

The correct answer is:
μ0i4π8a2+b2ab

Solution:
From figure it is clear that
BAB=BCD
=μ0i4πb2sin⁡ϕ1+sin⁡ϕ2=μ04π⋅4ib⋅aa2+b2
BBC=BDA=μ04π⋅4ia⋅ba2+b2
∴ B=BAB+BBC+BCD+BDA
B=2μ04π⋅4ib⋅aa2+b2+2μ04π⋅4ia⋅ba2+b2
B=μ04π⋅2×4ia2+b2ab+ba
B=μ04π⋅8ia2+b2ab

Topic: Physics, Magnetic Effects of Current, NEET
A rectangular loop of wire ABCD is kept close to an infinitely long wire carrying a current I(t ) = Io(1– t/ T ) for 0 ≤t ≤ T and I (0) = 0 for t > T (Fig). Find the total charge passing through a given point in the loop, in time T. The resistance of the loop is R.

Options:
A $\frac{{{\mu }_{o}}{{L}_{1}}{{I}_{1}}}{2\pi }ln\frac{{{L}_{2}}+x}{x}$
B $\frac{{{\mu }_{o}}{{L}_{1}}{{I}_{1}}}{3\pi }ln\frac{{{L}_{1}}+x}{x}$
C $\frac{{{\mu }_{o}}{{L}_{1}}{{I}_{1}}}{2\pi }ln\frac{{{L}_{1}}+x}{x}$
D $\frac{{{\mu }_{o}}{{L}_{1}}{{I}_{1}}}{3\pi }ln\frac{{{L}_{2}}+x}{x}$

The correct answer is:
$\frac{{{\mu }_{o}}{{L}_{1}}{{I}_{1}}}{2\pi }ln\frac{{{L}_{2}}+x}{x}$

Solution:
Correct Option is : (A)
$\frac{{{\mu }_{o}}{{L}_{1}}{{I}_{1}}}{2\pi }ln\frac{{{L}_{2}}+x}{x}$

Topic: Chemistry, Electromagnetic Induction, NEET
A rectangular wire loop with length a and width b lies in the xy -plane as shown. Within the loop, there is a time-dependent magnetic field given by Bâ= cxcosâ¡Ïti^+ysinâ¡Ïtk^. Here, c and Ï are constants. The magnitude of emf induced in the loop as a function of time is

Options:
A ab2c2ωcos⁡ωt
B ab2cωcos⁡ωt
C a2bc2ωsin⁡ωt
D None of the options

The correct answer is:
ab2c2ωcos⁡ωt

Solution:
from diagram only z component of magnetic field gives flux.
Flux through small elemental area
dÏ=ady cysinâ¡Ït
net flux =acsinâ¡Ïtâ«0by dy
Ï=acb22sinâ¡Ït
â´ Induced emf in the loop.
Îµ=ddtÏm=ddt.ab2c2sinâ¡Ït
Hence, Îµ=ab2c2Ïcosâ¡Ït

Topic: Physics, Electromagnetic Induction, NEET
A red colour flower with long corolla tubes, copious amount of nectar and without fragrance would mostly be

Options:
A entomophilous
B chirophtherophilous
C ornithophilous
D anemophilous

The correct answer is:
ornithophilous

Solution:
Flowers pollinated by birds are called ornithophilous flowers. They have a corolla tube formed by the fusion of petals. This allows the beak of the bird to be placed in the flower. They have a large amount of nectar. They are without fragrance since the birds cannot smell. Insect pollinated (entomophilous) flowers will be bright colored and with a sweet smell. Bat pollinated (chirophtherophilous) flowers are generally white flowers with rotting fruit odor. Wind pollinated (Anemophilous) flowers are small, not colored, and not fragrant.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
A ← Red P + HI CH 3 COOH → LiAlH 4 B. What is not true for A and B ?

Options:
A A is hydrocarbon of general formula C n H 2 n+2 while B belongs to alkanol
B A can be obtained by reducing CH3CH2Cl while B by its hydrolysis
C A is alkene while B is alkanal
D A and B both belongs to different homologous series

The correct answer is:
A is alkene while B is alkanal

Solution:
A–CH3CH3 it is reduction of carboxylic acid into alkane with Red P/HI and B-CH3CH2OH , reduction of carboxylic acid into alcohol by lithiumaluminium hydride.

Topic: Chemistry, Carboxylic Acid Derivatives, NEET
A redox reaction in which two molecules of an aldehyde react to produce a primary alcohol and a carboxylic acid using a hydroxide base is called:

Options:
A

Cannizzaro reaction

B

Acetylation

C

Decarboxylation

D

None of these

The correct answer is:

Cannizzaro reaction

Solution:
Cannizzaro reaction: Aldehydes which do not contain any Î± -hydrogen atom such as formaldehyde (HCHO) and benzaldehyde ( C 6 â H 5 âCHO) undergo self-oxidation and reduction reaction on treatment with concentrated alkali. A mtextxture of an alcohol and a salt of a carboxylic acid are formed.

HCHO+HCHO â NaOH C H 3 âOH+HâCOONa MethanalâââââââââââââââââââââMethanolââââSod.âformate

C 6 â H 5 âCHO â NaOH C 6 â H 5 C H 2 OH+ C 6 â H 5 âCOONa BenzaldehydeââââââââââââââââBenzylâalcoholâââââââSod.âbenzoate

Acetylation: The replacement of active hydrogen of alcohols, phenols or amtextnes with an acyl group to form the corresponding esters or amtextdes is called acylation.

C H 3 âCOCl+C H 3 âC H 2 âOH â Pyridine C H 3 âCOOâ C 2 â H 5 +HCl âââââAcetylââââââââââââââââââEthylââââââââââââââââââââââââââââââââââââââââEthylâacetate âââââchlorideâââââââââââââââalcohol

Decarboxylation: The process of removal of a molecule of C O 2 from a carboxylic acid is called decarboxylation It is carried out by beating a carboxylic acid with soda-lime (NaOH+CaO)âatâ630âK.

Topic: Chemistry, Aldehydes and Ketones, NEET
A reduction in the quantity of oxygen evolution during photosynthesis may be observed at

Options:
A Light having wavelength more than 680 nm
B Light having wavelength less than 680 nm
C Light having wavelength 560 nm
D Light having wavelength less than 360 nm

The correct answer is:
Light having wavelength more than 680 nm

Solution:
In far-red light (wavelength more than 680 nm), there is a reduction in the quantity of O2 evolution.
The evolution of oxygen as a result of light-driven water
oxidation in photosystem II (PSII) is catalyzed by an Mn2+ cluster that acts both as a device for accumulating oxidizing equivalents and as the active site.
Infrared ray disturbs this complex and hence reduction on O2 evolution.

Topic: Biology, Photosynthesis in Higher Plants, NEET
A refrigerator absorbs 2000 cal of heat from ice trays. If the coefficient of performance is 4, then work done by the motor is

Options:
A 2100 J
B 4200 J
C 8400 J
D 500 J

The correct answer is:
2100 J

Solution:
Q2=2000 cal

Coefficient of performance, COP=Q2W
W=Q2COP=500 calW=500×4.2 J=2100 J

Topic: Physics, Thermodynamics, NEET
A refrigerator absorbs 2000 cal of heat from ice trays. If the coefficient of performance is 4, then work done by the motor is

Options:
A 2100 J
B 4200 J
C 8400 J
D 500 J

The correct answer is:
2100 J

Solution:
Q2=2000 cal, as COP=Q2W
W=COPQ2=500 calW=500Ã4.2=2100 J

Topic: Physics, Thermodynamics, NEET
A refrigerator works between 4o C and 30oC. It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is:
(Take 1 cal = 4.2 Joules)

Options:
A 2.365 W
B 23.65âW
C 236.5âW
D 2365âW

The correct answer is:
236.5 W

Solution:
Q 2 Q 1 = T 2 T 1 ⇒ 600+w 600 = 303 277 = 277+26 277
1+w600=1+26277
w=600×26277×4.2
w=236.5

Topic: Physics, Thermodynamics, NEET, NEET 2016 (Phase 1)
A remote-sensing satellite of earth revolves in a circular orbit at a height of 0.25×106 m above the surface of earth. If earth's radius is 6.38×106 m and g=9.8 m s-2, then the orbital speed of the satellite is:
Mass of earth undefined

Options:
A 8.56 km s-1
B 9.13 km s-1
C 6.67 km s-1
D 7.76 km s-1

The correct answer is:
7.76 km s-1

Solution:
V0=GMr=GMR2.R2r
=9.8×6.38×6.386.63×106=60×106 m/sec
=7.76 km/sec

Topic: Physics, Gravitation, NEET, NEET 2015 (Phase 2)
A renewable exhaustible natural resource is

Options:
A coal
B petroleum
C minerals
D forest

The correct answer is:
forest

Solution:
Forest is renewable, exhaustible natural resource. Renewable resources are living, able to reproduce or replace themselves and to increase. The renewable resources get replenished, recycled or reproduced and can fast forever provided they are not used beyond their renewability. Exhaustible resource are the natural resources with finite stock or supply, they are vulnerable to both qualitative and quantitative degradation.
Coal and petroleum are non-renewable and exhaustible natural resources.
Minerals are renewable and inexhaustible natural resources.

Topic: Biology, Ecosystem, NEET, NEET 2010 (Screening)
A resistance R draws power P when connected to an AC source. If an inductance is now placed in series with the resistance, such that the impedance of the circuit becomes Z , the power drawn will be:

Options:
A PRZ2
B PRZ
C PRZ
D P

The correct answer is:
PRZ2

Solution:
We know
P=V2R ; P′=V.Vzcos⁡Φ
V2=PR & cos⁡Φ=Rz
P′=V2z Rz
⇒ PRz2 R=PR2z2
=PRz2

Topic: Physics, Alternating Current, NEET, NEET 2015 (Phase 1)
A resistance wire connected in the left gap of a metre bridge balances a 10 Ω resistance in the right gap at a point which divides the bridge wire in the ratio 3:2.
If the length of the resistance wire is 1.5 m, then the length of 1 Ω of the resistance wire is:

Options:
A 1.0×10−1 m
B 1.5×10−1 m
C 1.5×10−2 m
D 1.0×10−2 m

The correct answer is:
1.0×10−1 m

Solution:
R10=l1l2

R10=32

R=15 Ω

Length of 15Ω resistance wire is 1.5 m

∴ length of 1Ω resistance wire =1.515=0.1

=1.0×10−1 m

Topic: Physics, Current Electricity, NEET, NEET 2020 (Phase 1)
A resistor of 4 kΩ with tolerance 10% is connected in parallel with a resistor of 6 kΩ with tolerance 10%. The tolerance of the parallel combination is nearly

Options:
A 10%
B 20%
C 30%
D 40%

The correct answer is:
30%

Solution:
Rs=R1R2R1+R2,
∆RsRs×100
=∆R1R1×100+∆R2R2×100+∆(R1+R2)R1+R2×​100
Now, ∆R1=10100×4kΩ=0.4kΩ,
ΔR2=10100×6kΩ=0.6kΩ
Again, ∆RsRs×100=0.44×100+0.66×100
+0.4+0.610×100
=10+10+10=30

Topic: Physics, Units and Dimensions, NEET
A resistor of 6 kÎ© with tolerance 10% and another resistance of 4 kÎ© with tolerance 10% are connected in series. The tolerance of the combination is about

Options:
A 5%
B 10%
C 12%
D 15%

The correct answer is:
10%

Solution:
In series combination
R=R1+R2
=6+4=10 kΩ
Error in combination,
ΔR=ΔR1+ΔR2
=10100×6+10100×4
=0.6+0.4=1
ΔRR=110
=10%

Topic: Physics, Current Electricity, NEET
A resistor of 10 kÎ© having tolerance 10% is connected in series with another resistor of 20 kÎ© having tolerance 20%. The tolerance of the combination will be approximately

Options:
A 10%
B 13%
C 17%
D 20%

The correct answer is:
17%

Solution:
∆Rs=∆R1+∆R2=10100×10+20100×20 kΩ=5 kΩ
ΔRsRs×100=530×100=503=17%

Topic: Physics, Units and Dimensions, NEET
A reverse biased diode is

Options:
A
B
C
D

The correct answer is:

Solution:
In the given option (A),
-6 V<-3 V
Thus, biasing in option (A) is reversed.

Topic: Physics, Semiconductors, NEET
A rifle bullet loses 120th of its velocity in passing through a plank. The least number of such planks required to just stop the bullet is

Options:
A 5
B 10
C 11
D 20

The correct answer is:
11

Solution:
Given, 19v202-v2=2ax
and o2-v2=2anx
Dividing, n=- v21920v2-v2=11-19202
=20Ã2020+1920-19=40039=10.3
So, the bullet shall stop in 11th plank.

Topic: Physics, Motion In One Dimension, NEET