JEE Main 2021 · August session
JEE Main 26 August 2021, Shift 1
89 questions (1 more dropped by NTA): 30 numerical-answer and 59 multiple choice. 13 were rated hard and 24 easy. Its hard-question count was the 2nd highest of the 24 2021 shifts Lumi analysed. The biggest chapter was Complex Numbers and Quadratic Equations, with 3 questions.
- Questions
- 89
- 1 dropped by NTA
- Numerical answer
- 30
- 34% of the shift
- Hard
- 13
- 15% of the shift
- Chapters asked
- 66
- 12 questions with a figure
Key findings · 26 Aug 2021, Shift 1
- 1
13 hard questions (15%): the 2nd 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 10 of 29 rated hard; Physics had the most easy questions (12 of 30).
- 3
49 questions tested a new idea, one no earlier year had asked: 66% of the 74 questions tagged to an idea.
- 4
24 came back from 2020: the same idea had been asked in the 2020 shifts Lumi analysed.
- 5
40 shared an idea with another 2021 shift (54% of tagged questions). Shifts in the same year can test the same idea in a new setting.
- 6
Biggest chapters: Current Electricity in Physics (3), The d- and f-Block Elements in Chemistry (3) and Complex Numbers and Quadratic Equations in Maths (3).
The shift at a glance
Subjects, difficulty and chapters
Top chapters
Top chapters
Top chapters
- Single correct44 Q
- Numerical value30 Q
- Diagram based7 Q
- Two statements6 Q
- Other2 Q
- Calculation28 Q
- Multi-step27 Q
- Conceptual13 Q
- Application12 Q
- Recall6 Q
- Data or graph2 Q
- Diagram reading1 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 89 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
12 easy16 medium2 hard
- Q1
- Q2The rms speeds of the molecules of Hydrogen, Oxygen and Carbondioxide at the same temperature are , and respectively then :
Kinetic TheoryKinetic Theory of GasesMolecular Speed Types
EasySingle correctNew ideaIdea asked in 3 years
- Q3Identify the logic operation carried out by the given circuit :
Semiconductor Electronics: Materials, Devices and Simple CircuitsLogic GatesCombinational Logic Circuits
EasyDiagram based · figureIdea asked in 7 yearsAsked the year before
- Q4
- Q5A particular hydrogen like ion emits radiation of frequency Hz when it makes transition from n=3 to n=1. The frequency in Hz of radiation emitted in transition from n=2 to n=1 will be :
AtomsBohr's Atomic ModelRydberg Formula and Spectra
EasySingle correctIdea asked in 6 yearsAsked the year before
- Q6Two narrow bores of diameter 5.0 mm and 8.0 mm are joined together to form a U-shaped tube open at both ends. If this U-tube contains water, what is the difference in the level of two limbs of the tube. [Take surface tension of water…
Mechanical Properties of FluidsSurface TensionCapillary Difference in a U-Tube
EasySingle correctNew idea
- Q7In a photoelectric experiment ultraviolet light of wavelength 280 nm is used with lithium cathode having work function eV. If the wavelength of incident light is switched to 400 nm, find out the change in the stopping potential.…
Dual Nature of Radiation and MatterPhotoelectric EffectStopping Potential
EasySingle correctNew ideaIdea asked in 2 years
- Q8Car B overtakes another car A at a relative speed of . How fast will the image of car B appear to move in the mirror of focal length 10 cm fitted in car A, when the car B is 1.9 m away from the car A ?
Ray Optics and Optical InstrumentsSpherical MirrorsImage Velocity (Axial Motion)
MediumSingle correctIdea asked in 3 yearsAsked the year before
- Q9An inductor coil stores 64 J of magnetic field energy and dissipates energy at the rate of 640 W when a current of 8 A is passed through it. If this coil is joined across an ideal battery, find the time constant of the circuit in seconds :
Electromagnetic InductionInductanceEnergy Stored in Inductors
MediumSingle correctIdea asked in 5 yearsAsked the year before
- Q10A series LCR circuit driven by 300 V at a frequency of 50 Hz contains a resistance R=3 k, an inductor of inductive reactance and an unknown capacitor. The value of capacitance to maximize the average power should be : (take…
Alternating CurrentLCR ResonanceResonance Condition
EasySingle correctNew ideaIdea asked in 2 years
- Q11The fractional change in the magnetic field intensity at a distance ‘r’ from centre on the axis of current carrying coil of radius ‘a’ to the magnetic field intensity at the centre of the same coil is : (Take r < a).
Moving Charges and MagnetismBiot-Savart LawRatio of Axial to Central Magnetic Field
MediumSingle correctNew ideaIdea asked in 4 years
- Q12In the given figure, the emf of the cell is 2.2 V and if internal resistance is 0.6 . Calculate the power dissipated in the whole circuit :
Current ElectricityKirchhoff's LawsCircuit Symmetry Analysis
MediumDiagram based · figureNew ideaIdea asked in 4 years
- Q13A solid metal sphere of radius R having charge q is enclosed inside the concentric spherical shell of inner radius a and outer radius b as shown in figure. The approximate variation electric field as a function of distance r from centre O is given…
Electric Charges and FieldsGauss's LawField of Concentric Conducting Shells
MediumDiagram based · figureNew idea
- Q14The material filled between the plates of a parallel plate capacitor has resistivity 200 m. The value of capacitance of the capacitor is 2 pF. If a potential difference of 40 V is applied across the plates of the capacitor, then the value of leakage…
Current ElectricityDielectricsLeaky Dielectric and RC Equivalent
MediumSingle correctNew idea
- Q15Inside a uniform spherical shell : (a) the gravitational field is zero. (b) the gravitational potential is zero. (c) the gravitational field is same everywhere. (d) the gravitation potential is same everywhere. (e) all of the above Choose the most…
GravitationGravitational PotentialPotential of Spherical Shell
EasyOtherNew idea
- Q16The initial mass of a rocket is 1000 kg. Calculate at what rate the fuel should be burnt so that the rocket is given an acceleration of . The gases come out at a relative speed of with respect to the rocket :…
System of Particles and Rotational MotionNewton's Laws of MotionRocket Propulsion Thrust
MediumSingle correctNew idea
- Q17What equal length of an iron wire and a copper-nickel alloy wire, each of 2 mm diameter connected parallel to give an equivalent resistance of 3 ? (Given resistivities of iron and copper-nickel alloy wire are 12 cm and 51 cm…
Current ElectricityOhm's Law and ResistanceResistivity and Geometry
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q18The magnitude of vectors , and in the given figure are equal. The direction of with -axis will be :
Motion in a PlaneKinematics in 2DVector Component Resolution
MediumDiagram based · figureIdea asked in 4 yearsAsked the year before
- Q19Statement I : By doping silicon semiconductor with pentavalent material, the electrons density increases. Statement II : The n-type semiconductor has net negative charge. In the light of the above statements, choose the most appropriate answer from the…
Semiconductor Electronics: Materials, Devices and Simple Circuits
EasyTwo statements
- Q20
- Q21A uniform chain of length 3 meter and mass 3 kg overhangs a smooth table with 2 meter laying on the table. If k is the kinetic energy of the chain in joule as it completely slips off the table, then the value of k is __________. (Take )
Work, Energy and PowerWork and Kinetic EnergyConservation of Mechanical Energy
MediumNumerical valueNew ideaIdea asked in 4 years
- Q22Consider a badminton racket with length scales as shown in the figure. If the mass of the linear and circular portions of the badminton racket are same (M) and the mass of the threads are negligible, the moment of inertia of the racket about an axis…
System of Particles and Rotational MotionMoment of InertiaMOI of Composite Bodies
HardNumerical value · figureIdea asked in 5 yearsAsked the year before
- Q23A soap bubble of radius 3 cm is formed inside the another soap bubble of radius 6 cm. The radius of an equivalent soap bubble which has the same excess pressure as inside the smaller bubble with respect to the atmospheric pressure is __________ cm.
Mechanical Properties of FluidsSurface TensionPressure in Concentric Soap Bubbles
MediumNumerical valueNew idea
- Q24
- Q25Two short magnetic dipoles and each having magnetic moment of 1 are placed at point O and P respectively. The distance between OP is 1 meter. The torque experienced by the magnetic dipole due to the presence of is…
Magnetism and MatterMagnetic Dipole MomentMagnetic Field of a Short Dipole
MediumNumerical value · figureNew ideaIdea asked in 3 years
- Q26
- Q27White light is passed through a double slit and interference is observed on a screen 1.5 m away. The separation between the slits is 0.3 mm. The first violet and red fringes are formed 2.0 mm and 3.5 mm away from the central white fringes. The difference in…
Wave OpticsYoung's Double SlitYDSE Fringe Width
MediumNumerical valueIdea asked in 5 yearsAsked the year before
- Q28
- Q29Two spherical balls having equal masses with radius of 5 cm each are thrown upwards along the same vertical direction at an interval of 3 s with the same initial velocity of 35 m/s, then these balls collide at a height of __________ m. (take…
Motion in a Straight LineKinematics in 1DMeeting Point Condition
MediumNumerical valueNew ideaIdea asked in 2 years
- Q30A source and a detector move away from each other in absence of wind with a speed of 20 m/s with respect to the ground. If the detector detects a frequency of 1800 Hz of the sound coming from the source, then the original frequency of source considering…
WavesDoppler EffectGeneral Doppler Formula
MediumNumerical valueNew idea
Chemistry30 questions
10 easy19 medium1 hard
- Q31Given below are two statements : Statement I : Frenkel defects are vacancy as well as interstitial defects. Statement II : Frenkel defect leads to colour in ionic solids due to presence of F-centres. Choose the most appropriate answer for the statements from…
The Solid StateSolid State DefectsFrenkel Defect
EasyTwo statementsNew idea
- Q32Given below are two statements : Statement I : According to Bohr's model of an atom, qualitatively the magnitude of velocity of electron increases with decrease in positive charges on the nucleus as there is no strong hold on the electron by the nucleus.…
Structure of AtomBohr's Atomic TheoryElectron Velocity in Orbit
MediumTwo statementsNew ideaIdea asked in 2 years
- Q33
- Q34Which one of the following is correct for the adsorption of a gas at a given temperature on a solid surface ?
Surface ChemistryAdsorptionThermodynamics of Adsorption
EasySingle correctNew ideaIdea asked in 2 years
- Q35Given below are two statements. Statement I : The choice of reducing agents for metals extraction can be made by using Ellingham diagram, a plot of vs temperature. Statement II : The value of increases from left to…
General Principles and Processes of Isolation of ElementsMetallurgical ExtractionEllingham Diagram Basics
MediumTwo statementsIdea asked in 3 yearsAsked the year before
- Q36Which one of the following methods is most suitable for preparing deionized water ?
HydrogenHydrogen and HydridesIon-Exchange Resins for Water Softening
EasySingle correctNew ideaIdea asked in 2 years
- Q37
- Q38The incorrect statement is :
The p-Block ElementsGroup 17 & 18Halogen Reactivity Trends
MediumSingle correctNew ideaIdea asked in 2 years
- Q39Which one of the following when dissolved in water gives coloured solution in nitrogen atmosphere ?
The d- and f-Block Elementsd-Block ElementsColor and Catalysis
EasySingle correctNew ideaIdea asked in 4 years
- Q40The conversion of hydroxyapatite occurs due to presence of ions in water. The correct formula of hydroxyapatite is :
Environmental ChemistryDrinking Water Standards: Fluoride Limits
MediumSingle correctNew ideaIdea asked in 3 years
- Q41Which one of the following complexes is violet in colour ?
Coordination CompoundsAnion AnalysisSulfide Sodium Nitroprusside Test
MediumSingle correctNew ideaIdea asked in 3 years
- Q42
- Q43The major product formed in the following reaction is : [figure: reactant, arrow labelled HBr above, "Major Product" after the arrow; "(excess)" printed beneath the reactant]
HydrocarbonsAlkenes and AlkynesMarkovnikov's Rule Application
MediumSingle correct · figureIdea asked in 6 yearsAsked the year before
- Q44Among the following compounds I-IV, which one forms a yellow precipitate on reacting sequentially with (i) NaOH (ii) dil. (iii) ? [figure: four hexagonal-ring structures labelled I, II, III, IV]
Haloalkanes and HaloarenesSN1 and SN2 MechanismsReactivity of Allylic and Benzylic Halides
MediumDiagram based · figureNew ideaIdea asked in 2 years
- Q45The major products formed in the following reaction sequence A and B are : [figure: hexagonal ring joined to a carbonyl carbon (C=O) which carries ; arrow with above and KOH below, giving A + B]
Aldehydes, Ketones and Carboxylic AcidsAldol and CannizzaroHaloform Interference with Aldol
MediumOther · figureNew idea
- Q46The correct options for the products A and B of the following reactions are : [figure: hexagonal ring (inner circle) with OH at top; left arrow labelled (Excess) / gives A; right arrow labelled /…
Alcohols, Phenols and EthersAromatic HydrocarbonsOrtho-Para vs Meta Directing
MediumDiagram based · figureNew ideaIdea asked in 5 years
- Q47
- Q48
- Q49The polymer formed on heating Novolac with formaldehyde is :
PolymersNovolac Intermediate Formation
EasySingle correctNew ideaIdea asked in 2 years
- Q50Given below are two statements : Statement I : In the titration between strong acid and weak base methyl orange is suitable as an indicator. Statement II : For titration of acetic acid with NaOH phenolphthalein is not a suitable indicator. In the light of…
EquilibriumpH and BuffersIndicator Selection for Titrations
MediumTwo statementsNew ideaIdea asked in 2 years
- Q51An aqueous KCl solution of density 1.20 g mL has a molality of 3.30 mol kg. The molarity of the solution in mol L is __________. (Nearest integer) [ Molar mass of KCl = 74.5 ]
Some Basic Concepts of ChemistryMole ConceptMolarity and Molality Interconversion
MediumNumerical valueNew ideaIdea asked in 3 years
- Q52is an interhalogen T-shaped molecule. The number of lone pairs of electrons on A is ___________. (Integer answer)
The p-Block ElementsGroup 17 & 18Interhalogen Compounds
EasyNumerical valueNew ideaIdea asked in 3 years
- Q53
- Q54
- Q55The concentration in a mixture of 5.0 mL of 0.0504 M and 2 mL of 0.0210 M solution is M. The value of is __________. (Nearest integer) [Given and…
EquilibriumpH and BuffersBasic Buffer pH Calculation
MediumNumerical valueNew ideaIdea asked in 3 years
- Q56The following data was obtained for chemical reaction given below at 975 K. [NO] mol L | [] mol L | Rate mol Ls (A)…
Chemical KineticsRate LawsInitial Rates Method
EasyNumerical valueIdea asked in 5 yearsAsked the year before
- Q57
- Q58
- Q59
- Q60
Maths29 questions
2 easy17 medium10 hard
- Q61Out of all the patients in a hospital 89% are found to be suffering from heart ailment and 98% are suffering from lungs infection. If K% of them are suffering from both ailments, then K can not belong to the set :
Relations and FunctionsSets and RelationsVenn Diagrams
MediumSingle correctIdea asked in 3 yearsAsked the year before
- Q62The equation represents a circle with :
Complex Numbers and Quadratic EquationsComplex Numbers - Polar FormLocus of Argument Ratio (Circular Arc)
MediumSingle correctNew ideaIdea asked in 3 years
- Q63If , , , and , then the inverse of the matrix…
MatricesMatrix InverseProperties of Matrix Inverses
MediumSingle correctNew idea
- Q64Let . If the system of linear equations. …
DeterminantsCramer's RuleParameter Evaluation in Homogeneous Systems
MediumSingle correctIdea asked in 5 yearsAsked the year before
- Q66If is the co-efficient of in the expansion of , then the value of is equal to :
Binomial TheoremBinomial CoefficientsSecond Derivative Method for Sums
MediumSingle correctNew ideaIdea asked in 3 years
- Q67If the sum of an infinite GP is 15 and the sum of the squares of its each term is 150, then the sum of is :
Sequences and SeriesAP and GPInfinite GP Sum
MediumSingle correctIdea asked in 6 yearsAsked the year before
- Q68Let , . Then :
Inverse Trigonometric FunctionsInverse Trig IdentitiesMultiple Angle Inverse ID
HardSingle correctNew ideaIdea asked in 2 years
- Q69The value of is :
IntegralsDefinite Integral PropertiesModulus Function Interval Splitting
HardSingle correctIdea asked in 3 yearsAsked the year before
- Q70The value of is :
IntegralsIntegral as Limit of SumFractional or Multiple Upper Bounds
MediumSingle correctNew idea
- Q71The sum of solutions of the equation , is :
Trigonometric FunctionsGeneral SolutionsModulus Trigonometric Equations
HardSingle correctNew ideaIdea asked in 2 years
- Q72
- Q73
- Q74On the ellipse let P be a point in the second quadrant such that the tangent at P to the ellipse is perpendicular to the line . Let S and S' be the foci of the ellipse and e be its eccentricity. If A is the area of the…
Conic SectionsEllipse EccentricityArea of Foci-Minor Axis Triangle
HardSingle correctNew idea
- Q75A plane P contains the line , and is perpendicular to the plane . Then which of the following points lies on P ?
Three Dimensional GeometryPlanes in 3DFamily of Planes
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q76Let be a solution curve of the differential equation , . If , then the value of is :
Differential EquationsLinear Differential EquationsIntegrating Factor Calculation
HardSingle correctIdea asked in 7 yearsAsked the year before
- Q77Let and . If is a vector such that and , then is equal to :
Vector AlgebraCross ProductSolving Vector Equations with Cross Products
MediumSingle correctIdea asked in 6 yearsAsked the year before
- Q78
- Q79
- Q80The mean and standard deviation of 20 observations were calculated as 10 and 2.5 respectively. It was found that by mistake one data value was taken as 25 instead of 35. If and are the mean and standard deviation respectively for…
StatisticsVariance and SDCorrecting Incorrect Variance
MediumSingle correctIdea asked in 6 yearsAsked the year before
- Q81The number of three-digit even numbers, formed by the digits 0, 1, 3, 4, 6, 7 if the repetition of digits is not allowed, is __________.
Permutations and CombinationsPermutations of Distinct Objects
EasyNumerical valueIdea asked in 4 yearsAsked the year before
- Q82Let a, b , b 0. Define a function If is continuous at , then is equal to…
Continuity and DifferentiabilityContinuity at a Point
MediumNumerical valueIdea asked in 4 yearsAsked the year before
- Q83The sum of all integral values of k (k 0) for which the equation in has no real roots, is __________.
Complex Numbers and Quadratic EquationsQuadratic RootsNature of Roots
MediumNumerical valueIdea asked in 3 yearsAsked the year before
- Q84A wire of length 36 m is cut into two pieces, one of the pieces is bent to form a square and the other is bent to form a circle. If the sum of the areas of the two figures is minimum, and the circumference of the circle is k (meter), then…
Application of DerivativesMaxima and MinimaOptimization Problems
MediumNumerical valueIdea asked in 5 years
- Q85The area of the region S is __________.
Application of IntegralsArea Under CurvesArea Between Parabola and Line
MediumNumerical valueIdea asked in 4 yearsAsked the year before
- Q86If is an implicit function of such that , then at is equal to __________.
Continuity and DifferentiabilityChain RuleSecond Order Implicit Chain Rule
MediumNumerical valueIdea asked in 4 yearsAsked the year before
- Q87
- Q88
- Q89
- Q90
Dropped from the final key and left out of every count: Q65.
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.