JEE Main 2021 · August session
JEE Main 31 August 2021, Shift 2
90 questions: 30 numerical-answer and 60 multiple choice. 12 were rated hard and 27 easy. Its hard-question count was the joint 3rd highest of the 24 2021 shifts Lumi analysed. The biggest chapter was Application of Derivatives, with 3 questions.
- Questions
- 90
- none dropped
- Numerical answer
- 30
- 33% of the shift
- Hard
- 12
- 13% of the shift
- Chapters asked
- 71
- 13 questions with a figure
Key findings · 31 Aug 2021, Shift 2
- 1
12 hard questions (13%): the joint 3rd highest count of the 24 2021 shifts Lumi analysed. Across those shifts the hard share ran from 3% to 17%.
- 2
Maths was the hardest section, with 8 of 30 rated hard; Chemistry had the most easy questions (14 of 30).
- 3
56 questions tested a new idea, one no earlier year had asked: 72% of the 78 questions tagged to an idea.
- 4
22 came back from 2020: the same idea had been asked in the 2020 shifts Lumi analysed.
- 5
36 shared an idea with another 2021 shift (46% of tagged questions). Shifts in the same year can test the same idea in a new setting.
- 6
Biggest chapters: Current Electricity in Physics (2), Aldehydes, Ketones and Carboxylic Acids in Chemistry (2) and Application of Derivatives in Maths (3).
The shift at a glance
Subjects, difficulty and chapters
Top chapters
Top chapters
Top chapters
- Single correct42 Q
- Numerical value30 Q
- Diagram based10 Q
- Two statements3 Q
- Other2 Q
- Match the list2 Q
- Assertion–reason1 Q
- Calculation29 Q
- Multi-step28 Q
- Conceptual12 Q
- Application9 Q
- Recall9 Q
- Diagram reading2 Q
- Data or graph1 Q
Most common: Calculation.
Against the other 2021 shifts
This shift next to the 23 other 2021 shifts Lumi analysed
Shares are of each shift’s scored questions. The highlighted row is this shift.
| Shift | Questions | Easy | Hard | Numerical | New ideas | Multi-step |
|---|---|---|---|---|---|---|
| 24 Feb, Shift 1 | 90 | 36% | 7% | 33% | 68% | 24% |
| 24 Feb, Shift 2 | 88 | 43% | 5% | 32% | 63% | 21% |
| 25 Feb, Shift 1 | 90 | 23% | 11% | 33% | 65% | 30% |
| 25 Feb, Shift 2 | 89 | 35% | 10% | 34% | 67% | 24% |
| 26 Feb, Shift 1 | 88 | 50% | 3% | 33% | 78% | 17% |
| 26 Feb, Shift 2 | 90 | 27% | 12% | 33% | 80% | 29% |
| 16 Mar, Shift 2 | 90 | 31% | 7% | 33% | 69% | 33% |
| 17 Mar, Shift 1 | 89 | 39% | 8% | 34% | 61% | 26% |
| 17 Mar, Shift 2 | 89 | 36% | 17% | 34% | 66% | 32% |
| 18 Mar, Shift 1 | 90 | 40% | 9% | 33% | 74% | 24% |
| 18 Mar, Shift 2 | 90 | 34% | 9% | 33% | 63% | 28% |
| 22 Jul, Shift 2 | 90 | 40% | 12% | 33% | 67% | 28% |
| 25 Jul, Shift 1 | 90 | 31% | 13% | 33% | 56% | 34% |
| 25 Jul, Shift 2 | 90 | 48% | 3% | 33% | 63% | 27% |
| 3 Aug, Shift 1 | 90 | 32% | 11% | 33% | 68% | 21% |
| 3 Aug, Shift 2 | 90 | 32% | 7% | 33% | 61% | 24% |
| 4 Aug, Shift 1 | 90 | 40% | 8% | 33% | 62% | 29% |
| 4 Aug, Shift 2 | 90 | 32% | 7% | 33% | 65% | 41% |
| 26 Aug, Shift 1 | 89 | 27% | 15% | 34% | 66% | 30% |
| 26 Aug, Shift 2 | 89 | 21% | 9% | 34% | 60% | 28% |
| 27 Aug, Shift 1 | 90 | 27% | 13% | 33% | 63% | 34% |
| 27 Aug, Shift 2 | 90 | 29% | 9% | 33% | 72% | 29% |
| 31 Aug, Shift 1 | 90 | 27% | 11% | 33% | 70% | 24% |
| 31 Aug, Shift 2 | 90 | 30% | 13% | 33% | 72% | 31% |
New ideas: share of a shift’s questions testing an idea no earlier year had asked. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.
Drill down
What this shift asked, and its history
Every chapter this shift asked, with all its topics and ideas. Counts and squares cover every analysed shift from 2017 to 2026; rows this shift did not ask are faded, and each row lists this shift’s questions with the most recent from other shifts.
Squares are the 8 years with analysed shifts, 2017 to 2026. A number is the questions that year when there is more than one; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. Share is of the level above.
Every question
All 90 questions of this shift
The opening words of each question, with its chapter, topic, idea and how hard it was. Open one for the full text, options and the official answer. “New idea” means no earlier year had tested it.
Physics30 questions
11 easy16 medium3 hard
- Q1
- Q2
- Q3
- Q4Two thin metallic spherical shells of radii and () are placed with their centres coinciding. A material of thermal conductivity K is filled in the space between the shells. The inner shell is maintained at temperature and…
Thermal Properties of MatterHeat ConductionRadial Conduction in Spherical Shells
MediumSingle correctNew idea
- Q5
- Q6
- Q7A mixture of hydrogen and oxygen has volume cm, temperature K, pressure kPa and mass g. The ratio of masses of oxygen to hydrogen will be :
Kinetic TheoryIdeal Gas LawsIdeal Gas Equation
MediumSingle correctNew ideaIdea asked in 2 years
- Q8A block moving horizontally on a smooth surface with a speed of m/s splits into two parts with masses in the ratio of . If the smaller part moves at m/s in the same direction, then the fractional change in kinetic energy is :
System of Particles and Rotational MotionCollisionsMomentum in Explosions
MediumSingle correctNew ideaIdea asked in 3 years
- Q9The equivalent resistance of the given circuit between the terminals A and B is :
Current ElectricityKirchhoff's LawsShort Circuits and Equipotential Nodes
MediumDiagram based · figureNew ideaIdea asked in 3 years
- Q10A bob of mass 'm' suspended by a thread of length undergoes simple harmonic oscillations with time period T. If the bob is immersed in a liquid that has density times that of the bob and the length of the thread is increased by…
OscillationsPendulumsPendulum in Fluids
MediumSingle correctNew ideaIdea asked in 2 years
- Q11Four identical hollow cylindrical columns of mild steel support a big structure of mass kg. The inner and outer radii of each column are 50 cm and 100 cm respectively. Assuming uniform local distribution, calculate the compression strain of…
Mechanical Properties of SolidsElasticityHooke's Law
MediumSingle correctNew ideaIdea asked in 3 years
- Q12For a body executing S.H.M. : (a) Potential energy is always equal to its K.E. (b) Average potential and kinetic energy over any given time interval are always equal. (c) Sum of the kinetic and potential energy at any point of time is constant. (d) Average…
OscillationsEnergy in SHMAverage Energy Values
EasyOtherNew idea
- Q13
- Q14A system consists of two identical spheres each of mass 1.5 kg and radius 50 cm at the ends of a light rod. The distance between the centres of the two spheres is 5 m. What will be the moment of inertia of the system about an axis perpendicular to the rod…
System of Particles and Rotational MotionMoment of InertiaParallel Axis Theorem
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q15
- Q16If and are the input voltages (either 5 V or 0 V) and is the output voltage then the two gates represented in the following circuits (A) and (B) are :
Semiconductor Electronics: Materials, Devices and Simple CircuitsLogic GatesDiode Realization of OR and AND Gates
EasyDiagram based · figureNew ideaIdea asked in 2 years
- Q17A current of 1.5 A is flowing through a triangle, of side 9 cm each. The magnetic field at the centroid of the triangle is : (Assume that the current is flowing in the clockwise direction.)
Moving Charges and MagnetismBiot-Savart LawField at Center of Regular Polygon
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q18Statement I : To get a steady dc output from the pulsating voltage received from a full wave rectifier we can connect a capacitor across the output parallel to the load . Statement II : To get a steady dc output from the pulsating voltage received from…
Semiconductor Electronics: Materials, Devices and Simple CircuitsSemiconductor DiodesCapacitor Filter Smoothing
EasyTwo statementsNew idea
- Q19Consider two separate ideal gases of electrons and protons having same number of particles. The temperature of both the gases are same. The ratio of the uncertainty in determining the position of an electron to that of a proton is proportional to :
Dual Nature of Radiation and MatterMatter WavesWavelength Uncertainty via Heisenberg
MediumSingle correctNew idea
- Q20Choose the incorrect statement : (a) The electric lines of force entering into a Gaussian surface provide negative flux. (b) A charge 'q' is placed at the centre of a cube. The flux through all the faces will be the same. (c) In a uniform electric field net…
Electric Charges and FieldsGauss's LawElectric Flux Calculation
EasyOtherIdea asked in 4 yearsAsked the year before
- Q21Cross-section view of a prism is the equilateral triangle ABC shown in the figure. The minimum deviation is observed using this prism when the angle of incidence is equal to the prism angle. The time taken by light to travel from P (midpoint of BC) to A is…
Ray Optics and Optical InstrumentsPrism DeviationBase Parallel Property at Minimum Deviation
MediumNumerical value · figureNew idea
- Q22A sample of gas with is taken through an adiabatic process in which the volume is compressed from 1200 cm to 300 cm. If the initial pressure is 200 kPa. The absolute value of the workdone by the gas in the process ________ J.
ThermodynamicsThermodynamic ProcessesAdiabatic Process Analysis
MediumNumerical valueIdea asked in 7 yearsAsked the year before
- Q23A parallel plate capacitor of capacitance 200 F is connected to a battery of 200 V. A dielectric slab of dielectric constant 2 is now inserted into the space between plates of capacitor while the battery remain connected. The change in the electrostatic…
Electrostatic Potential and CapacitanceDielectricsDielectric with Battery Connected
EasyNumerical valueNew ideaIdea asked in 3 years
- Q24In a Young's double slit experiment, the slits are separated by 0.3 mm and the screen is 1.5 m away from the plane of slits. Distance between fourth bright fringes on both sides of central bright fringe is 2.4 cm. The frequency of light used is ________…
Wave OpticsYoung's Double SlitYDSE Fringe Width
EasyNumerical valueIdea asked in 5 yearsAsked the year before
- Q25
- Q26
- Q27
- Q28
- Q29A long solenoid with 1000 turns/m has a core material with relative permeability 500 and volume cm. If the core material is replaced by another material having relative permeability of 750 with same volume maintaining same current of 0.75 A in the…
Magnetism and MatterMagnetic Dipole MomentMagnetic Moment of a Solenoid
MediumNumerical valueNew idea
- Q30A resistor dissipates 192 J of energy in 1 s when a current of 4 A is passed through it. Now, when the current is doubled, the amount of thermal energy dissipated in 5 s is ________ J.
Current ElectricityOhm's Law and ResistanceJoule Heating and Power
EasyNumerical valueIdea asked in 6 yearsAsked the year before
Chemistry30 questions
14 easy15 medium1 hard
- Q31The incorrect expression among the following is :
Thermodynamics (Chemistry)Gibbs Free EnergyGibbs Energy and Equil
MediumSingle correctNew ideaIdea asked in 5 years
- Q32
- Q33
- Q34Which one of the following statements is incorrect ?
HydrogenHydrogen and HydridesH-H Bond Dissociation Enthalpy
MediumSingle correctNew idea
- Q35Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Lithium salts are hydrated. Reason (R) : Lithium has higher polarising power than other alkali metal group members. In the light of the…
The s-Block Elementss-Block ElementsHydration Enthalpy Trends
EasyAssertion–reasonNew ideaIdea asked in 3 years
- Q36The number of S=O bonds present in sulphurous acid, peroxodisulphuric acid and pyrosulphuric acid, respectively are :
The p-Block ElementsGroup 15 & 16Sulfur Oxoacids
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q37
- Q38In which one of the following sets all species show disproportionation reaction ?
Redox ReactionsDisproportionation Balancing
MediumSingle correctNew ideaIdea asked in 3 years
- Q39Spin only magnetic moment in BM of is :
Coordination CompoundsCrystal Field TheorySpin-only Magnetic Moment
MediumSingle correctIdea asked in 7 yearsAsked the year before
- Q40The deposition of X and Y on ground surfaces is referred as wet and dry depositions, respectively. X and Y are :
Environmental ChemistryAcid Rain Mechanism
EasySingle correctIdea asked in 4 yearsAsked the year before
- Q41The major product of the following reaction is : [reaction: starting material drawn as a five-membered ring; reagent above/below arrow: NaOH / C2H5OH; Major Product]
Haloalkanes and HaloarenesAlkenes and AlkynesSaytzeff vs. Hofmann Elimination
MediumDiagram based · figureIdea asked in 6 yearsAsked the year before
- Q42Arrange the following conformational isomers of n-butane in order of their increasing potential energy : [four Newman projections labelled I, II, III, IV]
HydrocarbonsAlkanes and Free RadicalsEthane and Butane Conformers
MediumDiagram based · figureNew ideaIdea asked in 2 years
- Q43For the following sequence of reactions, the correct products are : [benzene ring drawn with alternating double bonds] 1. Br2/Fe/ 2. Mg/dry ether 3. -> Products
Haloalkanes and HaloarenesAlkanes and Free RadicalsAlkane Synthesis via Grignard Protonation
MediumDiagram based · figureNew ideaIdea asked in 2 years
- Q44For the reaction given below : [benzene ring drawn with an inner circle; CHO attached at top, attached at bottom] 1. NaOH, 2. -> Product The compound which is not formed as a product in the reaction is a :
Aldehydes, Ketones and Carboxylic AcidsAldol and CannizzaroCannizzaro Reaction
MediumDiagram based · figureIdea asked in 4 yearsAsked the year before
- Q45The structures of A and B formed in the following reaction are : [Ph = ] [benzene ring (with inner circle) + a five-membered cyclic anhydride drawn as a ring containing O with two C=O groups] -> (AlCl(2 eq)) A -> (Zn/Hg, HCl) B
Aldehydes, Ketones and Carboxylic AcidsAromatic HydrocarbonsFriedel-Crafts Acylation and Acylium Ion
MediumDiagram based · figureNew ideaIdea asked in 2 years
- Q46Identify correct A, B and C in the reaction sequence given below : [benzene ring] conc. + conc. , -> A -> (, Anhyd. ) B -> (Fe/HCl) C
AminesAromatic HydrocarbonsOrtho-Para vs Meta Directing
MediumDiagram based · figureNew ideaIdea asked in 5 years
- Q47
- Q48Which among the following is not a polyester ?
PolymersPolyesters: Terylene vs Glyptal
EasySingle correctNew idea
- Q49
- Q50
- Q51Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is __________ M. (Nearest integer) [Atomic…
Some Basic Concepts of ChemistryMole ConceptMolarity Calculation
EasyNumerical valueIdea asked in 5 yearsAsked the year before
- Q52The empirical formula for a compound with a cubic close packed arrangement of anions and with cations occupying all the octahedral sites in . The value of is __________. (Integer answer)
The Solid StateCrystal LatticesEmpirical Formula from Void Occupancy
EasyNumerical valueIdea asked in 3 yearsAsked the year before
- Q53The value of magnetic quantum number of the outermost electron of ion is __________. (Integer answer)
Structure of AtomQuantum NumbersMagnetic Quantum Number
EasyNumerical valueIdea asked in 4 yearsAsked the year before
- Q54According to molecular orbital theory, the number of unpaired electron(s) in is __________.
Chemical Bonding and Molecular StructureMolecular Orbital TheoryMagnetic Property Prediction
EasyNumerical valueIdea asked in 6 yearsAsked the year before
- Q55
- Q56
- Q57
- Q58
- Q59In the electrolytic refining of blister copper, the total number of main impurities, from the following, removed as anode mud is __________. Pb, Sb, Se, Te, Ru, Ag, Au and Pt
General Principles and Processes of Isolation of ElementsMetallurgical ExtractionAnode Mud Composition
MediumNumerical valueNew idea
- Q60The transformation occurring in Duma’s method is given below The value…
Organic Chemistry: Some Basic Principles and TechniquesStoichiometryStoichiometry of Dumas Method
EasyNumerical valueIdea asked in 4 yearsAsked the year before
Maths30 questions
2 easy20 medium8 hard
- Q61
- Q62If is a complex number such that is purely imaginary, then the minimum value of is :
Complex Numbers and Quadratic EquationsComplex Numbers - Polar FormLocus of Argument Ratio (Circular Arc)
MediumSingle correctNew ideaIdea asked in 3 years
- Q63The sum of the roots of the equation, , is :
Complex Numbers and Quadratic EquationsQuadratic RootsExponential Reducible to Quadratic
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q64If , then the system of equations has :
DeterminantsCramer's RuleHomogeneous System Solutions
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q65Let be an A.P. If , , then is equal to :
Sequences and SeriesAP and GPAP Recognition from Quadratic Sum
MediumSingle correctNew ideaIdea asked in 2 years
- Q66
- Q67If and are the roots of the equation, , then the ordered pair is :
Limits and DerivativesL'Hopital's RuleIndeterminate Power Forms
MediumSingle correctNew ideaIdea asked in 3 years
- Q68Let be any continuous function on and twice differentiable on . If , and , then :
Application of DerivativesRolle's TheoremHigher-Order Derivative Roots
MediumSingle correctNew ideaIdea asked in 3 years
- Q69If is the greatest integer , then is equal to :
IntegralsDefinite Integral PropertiesGreatest Integer Function Integrals
HardSingle correctIdea asked in 7 yearsAsked the year before
- Q70If , , then for , the value of lies in the interval :
Differential EquationsVariable Separable FormDirect Integration
HardSingle correctNew ideaIdea asked in 3 years
- Q71If , , , and , then is equal to :
Differential EquationsHomogeneous EquationsHomogeneous Equations with Transcendental Functions
HardSingle correctNew ideaIdea asked in 2 years
- Q72Let A be the set of all points such that the area of triangle formed by the points , and is 12 square units. Then the least possible length of a line segment joining the origin to a point in A, is :
Straight LinesStraight Line DistanceLocus of Points at a Fixed Distance
MediumSingle correctNew ideaIdea asked in 2 years
- Q73
- Q74The distance of the point from the line of intersection of the planes and is :
Three Dimensional GeometryLines in 3DPerpendicular Distance from Point to Line
MediumSingle correctNew ideaIdea asked in 6 years
- Q75Let be three vectors mutually perpendicular to each other and have same magnitude. If a vector satisfies…
Vector AlgebraTriple ProductsVTP BAC-CAB Expansion
HardSingle correctNew ideaIdea asked in 2 years
- Q76Let . Then the probability that a randomly chosen onto function from S to S satisfies is :
ProbabilityPermutations and CombinationsNumber of Surjective (Onto) Functions
MediumSingle correctNew ideaIdea asked in 4 years
- Q77The mean and variance of 7 observations are 8 and 16 respetively. If two observations are 6 and 8, then the variance of the remaining 5 observations is :
StatisticsVariance and SDFinding Unknown Observations from Mean and Variance
MediumSingle correctIdea asked in 7 yearsAsked the year before
- Q78The number of solutions of the equation , is :
Trigonometric FunctionsGeneral SolutionsQuadratic Substitution in Trigonometry
MediumSingle correctNew ideaIdea asked in 5 years
- Q79
- Q80
- Q81The number of elements in the set , where…
MatricesMatrix MultiplicationBinomial Expansion for Commuting Matrices
MediumNumerical valueNew ideaIdea asked in 3 years
- Q82The number of 4-digit numbers which are neither multiple of 7 nor multiple of 3 is ______________.
Permutations and CombinationsPrinciple of Inclusion-Exclusion in Counting
MediumNumerical valueNew ideaIdea asked in 3 years
- Q83If the coefficient of in the expansion of is , then is equal to ______________.
Binomial TheoremPermutations and CombinationsMultinomial Theorem in Counting
MediumNumerical valueNew ideaIdea asked in 2 years
- Q84If , then is equal to ______________.
Sequences and SeriesArithmetico-Geometric SeriesSecond-Order AGP Summation
HardNumerical valueNew ideaIdea asked in 3 years
- Q85Let be a cubic polynomial with , , and has a local minima at , and has a local minima at . Then is equal to ______________.
Application of DerivativesMaxima and MinimaDetermining Coefficients from Extrema
MediumNumerical valueIdea asked in 3 yearsAsked the year before
- Q86
- Q87If the line bisects the area enclosed by the lines , , and the curve , then is equal to ______________.
Application of IntegralsArea Under CurvesBisection of Bounded Areas
MediumNumerical valueIdea asked in 2 yearsAsked the year before
- Q88Let B be the centre of the circle . Let the tangents at two points P and Q on the circle intersect at the point . Then is equal…
Conic SectionsCircle TangentsArea of Tangent-Chord Triangle
HardNumerical valueNew ideaIdea asked in 2 years
- Q89
- Q90Suppose the line lies on the plane . Then is equal to ______________.
Three Dimensional GeometryPlanes in 3DCondition for Line to Lie in Plane
MediumNumerical valueNew ideaIdea asked in 2 years
Questions from the official paper published by NTA, answers from the final key. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026; see the other 2021 shifts.