JEE Main 2021 · July session
JEE Main 4 August 2021, Shift 1
90 questions: 30 numerical-answer and 60 multiple choice. 7 were rated hard and 36 easy. Its hard-question count was the joint 16th 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
- 7
- 8% of the shift
- Chapters asked
- 65
- 12 questions with a figure
Key findings · 4 Aug 2021, Shift 1
- 1
7 hard questions (8%): the joint 16th 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 4 of 30 rated hard; Chemistry had the most easy questions (15 of 30).
- 3
47 questions tested a new idea, one no earlier year had asked: 62% of the 76 questions tagged to an idea.
- 4
26 came back from 2020: the same idea had been asked in the 2020 shifts Lumi analysed.
- 5
41 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: System of Particles and Rotational Motion in Physics (3), 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 correct50 Q
- Numerical value30 Q
- Diagram based5 Q
- Match the list4 Q
- Two statements1 Q
- Multi-step26 Q
- Calculation24 Q
- Application21 Q
- Recall13 Q
- Conceptual3 Q
- Diagram reading2 Q
- Data or graph1 Q
Most common: Multi-step.
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
13 easy15 medium2 hard
- Q1
- Q2
- Q3In a hydrogen atom, if energy of the n level is denoted by and , then for very large values of ‘n’ the ratio
AtomsBohr's Atomic ModelEnergy Level Calculations
MediumSingle correctNew ideaIdea asked in 6 years
- Q4A hypothetical radioactive nuclei decays according to the following series The atomic number and mass number of will be respectively
NucleiRadioactive DecayCounting Alpha and Beta Emissions
EasySingle correctNew ideaIdea asked in 2 years
- Q5
- Q6
- Q7The refractive index of a prism is 1.6. When prism is immersed in a liquid of 1.2 refractive index, then the change in the angle of minimum deviation will be ________. (Assume prism is equilateral) Given …
Ray Optics and Optical InstrumentsPrism DeviationPrism in Surrounding Medium
MediumSingle correctNew idea
- Q8
- Q9Assume there is a possibility of constant Electric field and Magnetic field and a charged particle under the influence of these forces tries to move along a circle. Identify which of the following are possible.
Moving Charges and MagnetismLorentz ForceCircular Motion in Uniform B-Field
EasySingle correctIdea asked in 4 yearsAsked the year before
- Q10
- Q11
- Q12
- Q13Choose the correct option for the centre of mass of a uniform disc of radius ‘R’ from which a circular section of radius r (2r < R) has been removed. The centre of the hole is at a distance ‘a’ from the centre of the disc. [Take the centre of the whole disc…
System of Particles and Rotational MotionCenter of MassCOM of Cavity Bodies
MediumSingle correctIdea asked in 2 yearsAsked the year before
- Q14
- Q15
- Q16A steel wire of 1 mm cross-sectional area having Young’s modulus N/m is stretched between two fixed points at a temperature of 40°C. The tension developed in the wire when its temperature falls to 30°C is given by (Coefficient of…
Thermal Properties of MatterThermal ExpansionThermal Stress
EasySingle correctIdea asked in 3 years
- Q17
- Q18
- Q19The moment of force acting at a point about the point is given by
System of Particles and Rotational MotionTorque and EquilibriumTorque Calculation
EasySingle correctIdea asked in 5 yearsAsked the year before
- Q20
- Q21A wire of length L is coated by another conducting material of double resistivity and the thickness of the layer is equal to the radius of the wire. The resistance of the wire between its ends after coating will decrease by ________%.
Current ElectricityOhm's Law and ResistanceResistivity and Geometry
MediumNumerical value · figureIdea asked in 4 yearsAsked the year before
- Q22A system shown in the figure is in equilibrium and at rest. The spring and string are massless. When the string is cut, the acceleration of mass ‘2m’ will be ________ m/s. (given g = 10 m/s)
Laws of MotionNewton's Laws of MotionInstantaneous Acceleration: Cutting Springs
EasyNumerical value · figureNew idea
- Q23A drop of liquid of mass kg falls away from the bottom of a charged conducting sphere of radius 20 cm, carrying with it a charge of 1nC and leaving on the sphere a uniformly distributed charge of 2.5C. The speed of the drop, after…
Electrostatic Potential and CapacitanceElectric PotentialWork Done in Field
HardNumerical valueIdea asked in 3 yearsAsked the year before
- Q24
- Q251 g of water at 100°C is converted into steam at the same temperature and at 1 atmospheric pressure. The change in internal energy is ________ J. [Consider latent heat of vaporisation is 2256 J/g and 1 atm = Pa] [Volume of water and steam at 1 atm = 1…
ThermodynamicsFirst Law of ThermodynamicsFirst Law in Phase Transitions
EasyNumerical valueNew ideaIdea asked in 2 years
- Q26The ratio of average speed to the rms speed of oxygen molecule is . The value of ‘x’ is ________ .
Kinetic TheoryKinetic Theory of GasesMolecular Speed Ratios
EasyNumerical valueNew ideaIdea asked in 4 years
- Q27
- Q28A potential difference of 800 V is applied across the plates of a parallel plate capacitor. The separation between the plates is 5 mm and a uniform magnetic field is applied parallel to the plates horizontally. An electron projected vertically parallel to…
Moving Charges and MagnetismLorentz ForceVelocity Selector and Crossed Fields
EasyNumerical valueNew ideaIdea asked in 3 years
- Q29
- Q30
Chemistry30 questions
15 easy14 medium1 hard
- Q31Match List I with List II List I List II A. Frenkel defect I. CsCl B. Schottky defect II. Pink LiCl C. Impurity defect III. ZnS D. Metal excess defect IV. Solid solution of CdCl and AgCl Choose the correct answer from the options given below :
The Solid StateSolid State DefectsFrenkel Defect
MediumMatch the listNew idea
- Q32Consider the following species Which set represents all paramagnetic species?
Chemical Bonding and Molecular StructureMolecular Orbital TheoryMagnetic Property Prediction
MediumSingle correctIdea asked in 6 yearsAsked the year before
- Q33For a gaseous reaction, , the rate of decomposition of may be studied by measuring the pressure (P) in a system at constant volume (V) and temperature (T). If all the gaseous species follow…
Chemical KineticsRate LawsRate and Stoichiometry
MediumSingle correctIdea asked in 5 yearsAsked the year before
- Q34Graph between , ('x' is mass of gas adsorbed and 'm' is the mass of adsorbent) versus log P (P-pressure of gas adsorbed) is a straight line (as depicted in the figure). It is applicable when
Surface ChemistryAdsorptionLimits of Freundlich Exponent (1/n)
MediumDiagram based · figureNew ideaIdea asked in 2 years
- Q35The correct order of first ionization enthalpy is :
Classification of Elements and Periodicity in PropertiesPeriodic Trendsp-Block Ionization Enthalpy Inversions
EasySingle correctNew ideaIdea asked in 4 years
- Q36The concentrated ores siderite and copper glance are converted to their oxides by
General Principles and Processes of Isolation of ElementsMetallurgical ExtractionCalcination vs. Roasting
EasySingle correctIdea asked in 3 yearsAsked the year before
- Q37
- Q38Choose the correct statement from the following :
The s-Block Elementss-Block ElementsFormation of Oxides, Peroxides, and Superoxides
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q39
- Q40Match List I with List II List I List II A. Gadolinium (At. No. 64) I. B. Holmium (At. No. 67) II. C. Neptunium (At. No. 93) III. D. Curium (At. No. 96) IV. Choose the correct answer…
The d- and f-Block Elementsf-Block ElementsLanthanide Electronic Configuration
MediumMatch the listIdea asked in 5 yearsAsked the year before
- Q41In stratosphere, chlorofluorocarbon compounds break down by UV radiations, releasing 'X' free radical, which further causes ozone layer depletion. Identify 'X'.
Environmental ChemistryOzone Layer Depletion
EasySingle correctIdea asked in 4 yearsAsked the year before
- Q42
- Q43Select the most suitable reagent for the following reduction reaction
HydrocarbonsAlkenes and AlkynesStereoselective Alkyne Reduction
EasySingle correct · figureNew ideaIdea asked in 3 years
- Q44Identify the reagent in the following reaction. (X = Cl, – Br)
Aldehydes, Ketones and Carboxylic AcidsCarboxylic Acids and DerivativesHell-Volhard-Zelinsky Reaction
EasySingle correct · figureNew ideaIdea asked in 4 years
- Q45Identify P in the given chemical reaction i) , KOH, heat ii)
Aldehydes, Ketones and Carboxylic AcidsAromatic HydrocarbonsSide-chain Oxidation
EasyDiagram based · figureNew ideaIdea asked in 5 years
- Q46Match List I with List II List I List II A. Kolbe's Reaction I. [structure: benzene ring with a CHO substituent] B. Gatterman-Koch Reaction II. [structure: benzene ring with OH and COOH on adjacent ring carbons] C. Reimer-Tiemann Reaction III. [structure:…
Alcohols, Phenols and EthersAlcohols and PhenolsReimer-Tiemann Reaction
MediumMatch the list · figureIdea asked in 4 yearsAsked the year before
- Q47Given below are two statements : Statement I : Benzenediazonium chloride is a colored crystalline solid. Statement II : Benzenediazonium fluoroborate is water soluble and stable at room temperature. In the light of the above statements, choose the most…
AminesDiazonium SaltsIsolation of Diazonium Fluoroborate
MediumTwo statementsNew idea
- Q48
- Q49
- Q50
- Q51A solution of has 30% by mass and a density of 1.25 g mL. The molarity of the solution is ________ M. (Nearest integer)
Some Basic Concepts of ChemistryMole ConceptMolarity Calculation
EasyNumerical valueIdea asked in 5 yearsAsked the year before
- Q52The wavelength of a tennis ball of mass 57 g travelling at 80 km h is ________ m. (Nearest integer) [Use : h = J s]
Structure of AtomMatter WavesBasic Wavelength-Momentum Relation
EasyNumerical valueIdea asked in 5 yearsAsked the year before
- Q53A lead bullet weighing 18 g and travelling with a velocity of 500 m/s is embedded in a wooden block weighing 1 kg. If both the block and the bullet were initially at 25°C, the final temperature of the block containing the bullet is ________ °C.…
Thermodynamics (Chemistry)First Law of ThermodynamicsMechanical Energy to Internal Energy Conversion
MediumNumerical valueNew idea
- Q54
- Q55If K of is at 298K, the molar solubility of in 0.2M is ________M. (Nearest integer)
EquilibriumSolubility ProductCommon Ion Effect
MediumNumerical valueNew ideaIdea asked in 4 years
- Q56For the reaction, ; The standard reduction potential for is V. The value…
ElectrochemistryNernst EquationStandard Cell Potential
EasyNumerical valueIdea asked in 7 years
- Q57Among the following species, the number of species with oxidation state of Fe in +3 is ________. A. [drawn structure, see figure_note] B. C.…
Coordination CompoundsCoordination NomenclatureOxidation State Calculation
MediumNumerical value · figureIdea asked in 4 yearsAsked the year before
- Q58Sum of unpaired electrons in and is ________.
Coordination CompoundsCrystal Field Theoryd8 Square Planar Preference
MediumNumerical valueNew ideaIdea asked in 2 years
- Q59
- Q60Number of isomeric compounds with molecular formula that will give carbylamine test is ________.
EasyNumerical valueIdea asked in 4 yearsAsked the year before
Maths30 questions
8 easy18 medium4 hard
- Q61The number of roots of the equation is
Complex Numbers and Quadratic EquationsQuadratic RootsExponential Reducible to Quadratic
MediumSingle correctIdea asked in 4 yearsAsked the year before
- Q62If and , then the set of points satisfying contains
Complex Numbers and Quadratic EquationsComplex Numbers - Polar FormModulus and Argument
MediumSingle correctIdea asked in 5 yearsAsked the year before
- Q63Let , and . If , then is equal to
DeterminantsMatrix InverseCofactor Matrix and Adjoint
MediumSingle correctIdea asked in 5 years
- Q64If the system of linear equations and has infinitely many solutions, then the ordered pair is
DeterminantsCramer's RuleCondition for Infinite Solutions
MediumSingle correctIdea asked in 7 yearsAsked the year before
- Q65If , then the value of is equal to
Binomial TheoremBinomial CoefficientsSum of Even and Odd Coefficients
MediumSingle correctNew ideaIdea asked in 3 years
- Q66
- Q67
Limits and DerivativesL'Hopital's Rulee-Power Shortcut for 1^infinity Forms
MediumSingle correctIdea asked in 3 yearsAsked the year before
- Q68The equation of the normal to the curve at a point, where the curve cuts the line is
Application of DerivativesTangents and NormalsEquation of Normal
EasySingle correctIdea asked in 3 yearsAsked the year before
- Q69If and , then the ratio is equal to
IntegralsDefinite Integral PropertiesKing's Property
MediumSingle correctIdea asked in 6 yearsAsked the year before
- Q70The equation of the tangent to the curve at the point whose abscissa is 1, is
Application of DerivativesTangents and NormalsEquation of Tangent
MediumSingle correctNew ideaIdea asked in 2 years
- Q71
- Q72If is an interior point of the triangle formed by the lines, , and , then the set of all values of k is the internal
Straight LinesStraight Line DistancePosition of points relative to line
MediumSingle correctIdea asked in 2 yearsAsked the year before
- Q73Consider a family of circles which pass through the point and touch the axis of . If the centre of such a circle is at , then the set of all values of is the interval
Conic SectionsCircle TangentsFamily of Circles Touching a Line
MediumSingle correctIdea asked in 5 yearsAsked the year before
- Q74
- Q75
- Q76
- Q77
- Q78Two players A and B play a game. Player A first throws a fair die and if 5 or 6 appears, he wins; otherwise player B throws a fair coin and wins if head comes. The process continues till someone wins. The probability that B wins after completion of 3 or more…
ProbabilityConditional ProbabilityConditional Probability in Infinite Games
MediumSingle correctNew idea
- Q79
- Q80
- Q81
- Q82Let , where If , then value of is ________. (Here, denotes transpose of ).
MatricesMatrix MultiplicationRow-by-Column Multiplication
EasyNumerical valueNew ideaIdea asked in 2 years
- Q83Each of the numbers 1, 0, -1 is written on two different opposite faces of a six foces fair die. This die is thrown three times. The number of ways in which the sum of the numbers appearing is zero, is ________.
Permutations and CombinationsPermutations with Repetition
MediumNumerical valueIdea asked in 4 yearsAsked the year before
- Q84
- Q85The local minimum value of , , is ________.
Application of DerivativesMaxima and MinimaSecond Derivative Test
EasyNumerical valueNew idea
- Q86If , then the value of is ________. (Here, C is a constant of integration).
IntegralsIntegration by SubstitutionTwin Trigonometric Integrals Substitution
HardNumerical valueNew ideaIdea asked in 2 years
- Q87
- Q88If the distance between the point and the plane passing through the points , and is , then the value of 'a' is ________.
Three Dimensional GeometryPlanes in 3DPlane Through Three Points
MediumNumerical valueNew ideaIdea asked in 2 years
- Q89The number of points in , where the function given by is NOT differentiable, is ________.
Continuity and DifferentiabilityDifferentiability of Modulus Functions
MediumNumerical valueNew ideaIdea asked in 5 years
- Q90If is equal to the integral solution of the inequality and is equal to the slope of the angle bisector of the second quadrant, then is ________.
Trigonometric FunctionsTrigonometric IdentitiesCompound Angle Formulas
MediumNumerical valueIdea asked in 5 yearsAsked the year before
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.