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JEE Main 2021 February 24, Shift 2 Question Paper with Solutions

All 90 questions from the JEE Main 2021 (February 24, Shift 2) shift — Physics (30), Chemistry (30) and Mathematics (30) — each with the correct answer (answer key) and a step-by-step solution. Read it free online, or attempt the full paper as a timed mock test.

Physics30 questions

Q1Single correctUnits and Measurements
The period of oscillation of a simple pendulum is . Measured value of L is from meter scale having a minimum division of and time of one complete oscillation is measured from stopwatch of resolution. The percentage error in the determination of g will be:
(A)
(B)
(C)
(D)
Q2Single correctWork, Energy and Power
A particle is projected with velocity along x-axis. A damping force is acting on the particle which is proportional to the square of the distance from the origin i.e. . The distance at which the particle stops:
(A)
(B)
(C)
(D)
Q3Single correctRotational Motion
A circular hole of radius is cut out of a circular disc of radius a as shown in figure. The centroid of the remaining circular portion with respect to point O will be:
Circular disc radius a centred at distance a from O on the x-axis, with a circular hole of radius a/2 cut tangent to the right edge.
(A)
(B)
(C)
(D)
Q4Single correctGravitation
A body weighs on a spring balance at the north pole. What will be its weight recorded on the same weighing machine, if it is shifted to the equator?
[Use and radius of earth, .]
(A)
(B)
(C)
(D)
Q5Single correctThermodynamics
If one mole of an ideal gas at is allowed to expand reversibly and isothermally (A to B) its pressure is reduced to one-half of the original pressure (see figure). This is followed by a constant volume cooling till its pressure is reduced to one-fourth of the initial value (). Then it is restored to its initial state by a reversible adiabatic compression (C to A). The net workdone by the gas is equal to:
P-V cycle: isotherm A(V1,P1) to B(2V1,P1/2), isochore B to C(2V1,P1/4), adiabatic compression C to A.
(A)
(B)
(C)
(D)
Q6Single correctKinetic Theory of Gases
On the basis of kinetic theory of gases, the gas exerts pressure because its molecules:
(A)
(B)
(C)
(D)
Q7Single correctOscillations and Waves
In the given figure, a body of mass is held between two massless springs, on a smooth inclined plane. The free ends of the springs are attached to firm supports. If each spring has spring constant , the frequency of oscillation of given body is:
Block M on a smooth incline of angle alpha, held between two springs (each constant k) attached to supports at the top and bottom of the incline.
(A)
(B)
(C)
(D)
Q8Single correctOscillations and Waves
When a particle executes SHM, the nature of graphical representation of velocity as a function of displacement is:
(A)
(B)
(C)
(D)
Q9Single correctOscillations and Waves
Which of the following equations represents a travelling wave?
(A)
(B)
(C)
(D)
Q10Single correctElectrostatics
Two electrons each are fixed at a distance . A third charge proton placed at the midpoint is displaced slightly by a distance perpendicular to the line joining the two fixed charges. Proton will execute simple harmonic motion having angular frequency:
( mass of charged particle)
(A)
(B)
(C)
(D)
Q11Single correctMagnetic Effects of Current and Magnetism
A soft ferromagnetic material is placed in an external magnetic field. The magnetic domains:
(A)
(B)
(C)
(D)
Q12Single correctElectromagnetic Induction and Alternating Currents
The figure shows a circuit that contains four identical resistors with resistance , two identical inductors with inductance and an ideal battery with E.M.F. . The current i just after the switch S is closed will be:
9 V battery with switch S feeding three parallel branches (R; L in series with R; R in series with L) and a series R in the bottom rail.
(A)
(B)
(C)
(D)
Q13Single correctDual Nature of Matter and Radiation
An X-ray tube is operated at million volt. The shortest wavelength of the produced photon will be:
(A)
(B)
(C)
(D)
Q14Single correctElectromagnetic Waves
Match List - I with List - II.
List-IList-II
(a). Source of microwave frequency(i). Radioactive decay of nucleus
(b). Source of infrared frequency(ii). Magnetron
(c). Source of Gamma Rays(iii). Inner shell electrons
(d). Source of X-rays(iv). Vibration of atoms and molecules
(v). LASER
(vi). RC circuit
(A)
(B)
(C)
(D)
Q15Single correctOptics
If the source of light used in a Young's double slit experiment is changed from red to violet:
(A)
(B)
(C)
(D)
Q16Single correctDual Nature of Matter and Radiation
The de Broglie wavelength of a proton and -particle are equal. The ratio of their velocities is
(A)
(B)
(C)
(D)
Q17Single correctAtoms and Nuclei
According to Bohr atom model, in which of the following transitions will the frequency be maximum?
(A)
(B)
(C)
(D)
Q18Single correctElectronic Devices
The logic circuit shown above is equivalent to :
A and (B through a NOT gate) feed an OR gate whose output passes through a NOT gate to C.
(A)
(B)
(C)
(D)
Q19Single correctElectronic Devices
Zener breakdown occurs in a junction having and both:
(A)
(B)
(C)
(D)
Q20Single correctElectronic Devices
Given below are two statements:
Statement I : junction diodes can be used to function as a transistor, simply by connecting two diodes, back to back, which acts as the base terminal
Statement II: In the study of transistors, the amplification factor indicates ratio of the collector current to the base current.
In the light of the above statements, choose the correct answer from the options given below.
(A)
(B)
(C)
(D)
Q21NumericalWork, Energy and Power
Two solids A and B of mass kg and kg respectively are moving with equal linear momentum. The ratio of their kinetic energies will be , so the value of A will be __________.
Q22NumericalRotational Motion
A uniform thin bar of mass kg and length meter is bent to make an equilateral hexagon. The moment of inertia about an axis passing through the centre of mass and perpendicular to the plane of hexagon is __________ .
Q23NumericalProperties of Solids and Liquids
A uniform metallic wire is elongated by m when subjected to a linear force F. The elongation, if its length and diameter is doubled and subjected to the same force will be __________ cm.
Q24NumericalKinetic Theory of Gases
The root-mean-square speed of molecules of a given mass of a gas at and atmosphere pressure is . The root-mean-square speed of molecules of the gas at and atmosphere pressure is . The value of x will be __________.
Q25NumericalOscillations and Waves
Two cars are approaching each other at an equal speed of . When they see each other, both blow horns having a frequency of Hz. The beat frequency heard by each driver will be __________ Hz. [Velocity of sound in air is ].
Q26NumericalElectrostatics
A point charge of is at a distance cm vertically above the centre of a square of side cm as shown in figure. The magnitude of the electric flux through the square will be __________ .
A +q point charge 6 cm vertically above the centre of a square of side 12 cm shown in perspective.
Q27NumericalCurrent Electricity
A cylindrical wire of radius mm and conductivity is subjected to an electric field of mV . The expected value of current in the wire will be mA. The value of x is __________.
Q28NumericalElectromagnetic Induction and Alternating Currents
A series LCR circuit is designed to resonate at an angular frequency . The circuit draws W power from V source at resonance. The value of resistance R in the circuit is __________ .
Q29NumericalElectromagnetic Waves
An electromagnetic wave of frequency GHz enters a dielectric medium of relative electric permittivity from vacuum. The wavelength of this wave in that medium will be __________ cm.
Q30NumericalElectromagnetic Waves
A signal of kW is transmitted in a cable. The attenuation of cable is dB per km and cable length is km. The power received at the receiver is W. The value of x is __________. [Gain in dB ]

Chemistry30 questions

Q31Single correctAtomic Structure
According to Bohr's atomic theory:
(A) Kinetic energy of electron is .
(B) The product of velocity (v) of electron and principal quantum number (n), .
(C) Frequency of revolution of electron in an orbit is .
(D) Coulombic force of attraction on the electron is .
Choose the most appropriate answer from the options given below:
(A)
(B)
(C)
(D)
Q32Single correctChemical Bonding and Molecular Structure
The correct set from the following in which both pairs are in correct order of melting point is:
(A)
(B)
(C)
(D)
Q33Single correctChemical Bonding and Molecular Structure
The correct shape and bond angles respectively in ion are:
(A)
(B)
(C)
(D)
Q34Single correctClassification of Elements and Periodicity in Properties
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Hydrogen is the most abundant element in the Universe, but it is not the most abundant gas in the troposphere.
Reason R: Hydrogen is the lightest element.
In the light of the above statements, choose the correct answer from the options given below:
(A)
(B)
(C)
(D)
Q35Single correctPrinciples Related to Practical Chemistry
Match List - I with List - II.
List-I (Salt)List-II (Flame colour wavelength)
(a). (i).
(b). (ii).
(c). (iii).
(d). (iv).
(A)
(B)
(C)
(D)
Q36Single correctHydrocarbons
Which one of the following compounds is non-aromatic?
(A)
(B)
(C)
(D)
Q37Single correctOrganic Compounds Containing Nitrogen
What is the correct sequence of reagents used for converting nitrobenzene into m-dibromobenzene?
Nitrobenzene converted through four sequential steps into m-dibromobenzene.
(A)
(B)
(C)
(D)
Q38Single correctOrganic Compounds Containing Halogens
The correct order of the following compounds showing increasing tendency towards nucleophilic substitution reaction is:
Four benzene structures (i) chlorobenzene, (ii) p-nitrochlorobenzene, (iii) 2,4-dinitrochlorobenzene, (iv) 2,4,6-trinitrochlorobenzene.
(A)
(B)
(C)
(D)
Q39Single correctPrinciples Related to Practical Chemistry
Given below are two statements:
Statement I: The value of the parameter "Biochemical Oxygen Demand (BOD)" is important for survival of aquatic life.
Statement II: The optimum value of BOD is .
In the light of the above statements, choose the most appropriate answer from the options given below:
(A)
(B)
(C)
(D)
Q40Single correctSome Basic Principles of Organic Chemistry
Most suitable salt which can be used for efficient clotting of blood will be?
(A)
(B)
(C)
(D)
Q41Single correctd- and f-Block Elements
Match List - I with List - II.
List-I (Metal)List-II (Ores)
(a). (i).
(b). (ii).
(c). (iii).
(d). (iv).
(A)
(B)
(C)
(D)
Q42Single correctd- and f-Block Elements
The incorrect statement among the following is:
(A)
(B)
(C)
(D)
Q43Single correctd- and f-Block Elements
What is the correct order of the following elements with respect to their density?
(A)
(B)
(C)
(D)
Q44Single correctCoordination Compounds
The calculated magnetic moments (spin only value) for species , and respectively are:
(A)
(B)
(C)
(D)
Q45Single correctOrganic Compounds Containing Oxygen
Which of the following reagent is suitable for the preparation of the product in the above reaction?
Carvone reacting with a reagent (?) to give limonene (ketone reduced to CH2).
(A)
(B)
(C)
(D)
Q46Single correctHydrocarbons
Which one of the following carbonyl compounds cannot be prepared by addition of water on an alkyne in the presence of and ?
(A)
(B)
(C)
(D)
Q47Single correctOrganic Compounds Containing Nitrogen
The diazonium salt of which of the following compounds will form a coloured dye on reaction with -Naphthol in NaOH?
(A)
(B)
(C)
(D)
Q48Single correctOrganic Compounds Containing Oxygen
Match List - I with List - II.
List-I (Salt)List-II (Flame colour wavelength)
a. i.
b. ii.
c. iii.
d. iv.
(A)
(B)
(C)
(D)
Q49Single correctSome Basic Principles of Organic Chemistry
In polymer Buna-S 'S' stands for:
(A)
(B)
(C)
(D)
Q50Single correctBiomolecules
Match List - I with List - II.
List-IList-II
a. Valiumi. Antifertility drug
b. Morphineii. Pernicious anaemia
c. Norethindroneiii. Analgesic
d. Vitamin iv. Tranquilizer
(A)
(B)
(C)
(D)
Q51NumericalSome Basic Concepts in Chemistry
The formula of a gaseous hydrocarbon which requires 6 times of its own volume of for complete oxidation and produces 4 times its own volume of is . The value of y is __________.
Q52NumericalPrinciples Related to Practical Chemistry
1.86 g of aniline completely reacts to form acetanilide. 10% of the product is lost during purification. Amount of acetanilide obtained after purification (in g) is __________ .
Q53NumericalSome Basic Concepts in Chemistry
The volume occupied by 4.75 g of acetylene gas at and 740 mm Hg pressure is __________ L.
(Rounded off to the nearest integer)
[Given ]
Q54NumericalChemical Thermodynamics
Assuming ideal behaviour, the magnitude of log K for the following reaction at is . The value of x is __________. (Integer answer)
[Given:
]
Q55NumericalEquilibrium
The solubility product of is . The solubility of lead iodide in 0.1 molar solution of lead nitrate is mol /L. The value of x is __________ (Rounded off to the nearest integer)
[Given ]
Q56NumericalSolutions
freezes at . The temperature at which a solution of 10 g of in 200 g of freeze is __________ . (nearest integer value), (The molal freezing point depression constant of is .)
Q57NumericalRedox Reactions and Electrochemistry
The magnitude of the change in oxidising power of the couple is V if the concentration is decreased from 1 M to M at . (Assume concentration of and to be same on change in concentration). The value of x is __________.
(Rounded off to the nearest integer)
[Given: ]
Q58NumericalChemical Kinetics
Sucrose hydrolyses in acid solution into glucose and fructose following first order rate law with a half-life of 3.33 h at . After 9 h, the fraction of sucrose remaining is f. The value of is __________ .
(Rounded off to the nearest integer)
[Assume: ln10 = 2.303, ln 2 = 0.693]
Q59Numericalp-Block Elements
Among the following allotropic forms of sulphur, the number of allotropic forms, which will show paramagnetism is __________.
(A) -sulphur
(B) -sulphur
(C) -form
Q60NumericalOrganic Compounds Containing Nitrogen
The total number of amines among the following which can be synthesized by Gabriel synthesis is __________.
Four amine structures labelled A, B, C, D.

Mathematics30 questions

Q61Single correctComplex Numbers and Quadratic Equations
Let a, b, c be in arithmetic progression. Let the centroid of the triangle with vertices (a, c), and (a, b) be . If are the roots of the equation , then the value of is:
(A)
(B)
(C)
(D)
Q62Single correctPermutations and Combinations
If is a positive integer, then the sum of the series is
(A)
(B)
(C)
(D)
Q63Single correctLimit, Continuity and Differentiability
If P is a point on the parabola which is closest to the straight line , then the co-ordinates of P are:
(A)
(B)
(C)
(D)
Q64Single correctSets, Relations and Functions
The negation of the statement is:
(A)
(B)
(C)
(D)
Q65Single correctSets, Relations and Functions
For the statements p and q, consider the following compound statements:


Then which of the following statements is correct?
(A)
(B)
(C)
(D)
Q66Single correctTrigonometry
The angle of elevation of a jet plane from a point A on the ground is . After a flight of seconds at the speed of km / hour, the angle of elevation changes to . If the jet plane is flying at a constant height, then its height is:
(A)
(B)
(C)
(D)
Q67Single correctMatrices and Determinants
For the system of linear equations:

Consider the following statements:
(A) The system has unique solution if .
(B) The system has unique solution if .
(C) The system has unique solution if .
(D) The system has no-solution if .
(E) The system has infinite number of solutions if .
Which of the following statements are correct?
(A)
(B)
(C)
(D)
Q68Single correctMatrices and Determinants
Let A and B be real matrices such that A is a symmetric matrix and B is a skew-symmetric matrix. Then the system of linear equations , where X is a column matrix of unknown variables and O is a null matrix, has
(A)
(B)
(C)
(D)
Q69Single correctTrigonometry
A possible value of is:
(A)
(B)
(C)
(D)
Q70Single correctCo-ordinate Geometry
For which of the following curves, the line is the tangent at the point ?
(A)
(B)
(C)
(D)
Q71Single correctLimit, Continuity and Differentiability
Let be defined as

Let . Then A is equal to:
(A)
(B)
(C)
(D)
Q72Single correctLimit, Continuity and Differentiability
If the curve , passes through the point and the tangent line to this curve at origin is , then the possible values of a,\ b,\ c are:
(A)
(B)
(C)
(D)
Q73Single correctIntegral Calculus
The value of the integral, , where [x] denotes the greatest integer less than or equal to x, is
(A)
(B)
(C)
(D)
Q74Single correctIntegral Calculus
The area of the region: is
(A)
(B)
(C)
(D)
Q75Single correctLimit, Continuity and Differentiability
Let f be a twice differentiable function defined on R such that and for all . If , for all , then the value of lies in the interval
(A)
(B)
(C)
(D)
Q76Single correctDifferential Equations
If a curve passes through the point and satisfies , then for what value of b, ?
(A)
(B)
(C)
(D)
Q77Single correctIntegral Calculus
Let f(x) be a differentiable function defined on such that for all , and . Then the value of is
(A)
(B)
(C)
(D)
Q78Single correctThree Dimensional Geometry
The vector equation of the plane passing through the intersection of the planes and , and the point is:
(A)
(B)
(C)
(D)
Q79Single correctThree Dimensional Geometry
Let . If the mirror image of the point with respect to the line is , then is equal to:
(A)
(B)
(C)
(D)
Q80Single correctStatistics and Probability
The probability that two randomly selected subsets of the set have exactly two elements in their intersection, is:
(A)
(B)
(C)
(D)
Q81NumericalComplex Numbers and Quadratic Equations
The number of the real roots of the equation is ________.
Q82NumericalComplex Numbers and Quadratic Equations
Let . If , and be the greatest integral part of . Then is equal to ________.
Q83NumericalPermutations and Combinations
The students are to be divided into 3 groups A,\ B and C such that each group has at least one student and the group C has at most 3 students. Then the total number of possibilities of forming such groups is ________.
Q84NumericalSequence and Series
The sum of first four terms of a geometric progression (G. P. ) is and the sum of their respective reciprocals is . If the product of first three terms of the G. P. is 1, and the third term is , then is ________.
Q85NumericalBinomial Theorem and its Simple Applications
For integers n and r, let . The maximum value of k for which the sum is maximum, is equal to ________.
Q86NumericalCo-ordinate Geometry
Let a point P be such that its distance from the point is thrice the distance of P from the point . If the locus of the point P is a circle of radius r, then (in the nearest integer) is equal to ________.
Q87NumericalStatistics and Probability
If the variance of 10 natural numbers is less than 10, then the maximum possible value of k is ________.
Q88NumericalSets, Relations and Functions
If and , then the value of the expression is ________.
Q89NumericalCo-ordinate Geometry
If the area of the triangle formed by the x-axis, the normal and the tangent to the circle at the point is A, then is equal to ________.
Q90NumericalThree Dimensional Geometry
Let be an integer. If the shortest distance between the lines and is , then the value of is ________.

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Frequently Asked Questions

How many questions are in the JEE Main 2021 February 24, Shift 2 paper?

The JEE Main 2021 February 24, Shift 2 paper has 90 questions — Physics (30), Chemistry (30) and Mathematics (30). Every question is on this page with its correct answer and a step-by-step solution.

What is the marking scheme for JEE Main?

JEE Main awards +4 marks for each correct answer and −1 for a wrong answer, with 0 for questions left unattempted. The paper covers Physics, Chemistry and Mathematics.

Are the answer key and step-by-step solutions provided for the 2021 February 24, Shift 2 paper?

Yes — every question shows the correct answer (answer key) and a detailed step-by-step solution, free to read online.

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