**JEE Main 24 Feb 2021 Question Paper with Answer Key** – The JEE Main 24 Feb 2021 answer key, question paper, solutions are now available for shift 1 and shift 2 both. You can view the questions asked with answers. Also download the keys by Resonance, Reliable Kota and other academies. Today’s paper was paper 1 of JEE Main 2021 (for BE / B.Tech) candidates. Youtube channels such as Gradeup, Unacademy, Vedantu have also released exam analysis, questions discussion, and paper solution. Coaching centers like Resonance, FIITJEE, Allen have also published JEE Main 24 February 2021 question paper with answers as PDFs. Later, NTA will release the official answer key at jeemain.nta.nic.in which you can challenge. Get all versions of JEE Main 2021 (24 Feb Morning / Evening Shift 1 / 2) physics, chemistry, mathematics question paper, answer key, solutions here.

**Check**: JEE Main 25 Feb 2021 Answer Key Available Now!

**All Post-Exam Resources:** **JEE Main 2021 Question Paper** , **JEE Main 2021 Answer Key**, **JEE Main 2021 Exam Analysis**.

## JEE Main 24 Feb 2021 Question Paper with Answer Key

### JEE Main 2021 Answer Key by Gradeup

From the table below candidates can download the JEE Main 2021 answer key by Gradeup

JEE Main 2021 Shifts | Physics | Chemistry | Maths |
---|---|---|---|

24 Feb – Shift 1 | Download PDF | Download PDF | Download PDF |

24 Feb – Shift 2 | Download PDF | Download PDF | Download PDF |

### JEE Main 2021 Answer Key by Resonance

From the table below candidates can download the JEE Main 2021 answer key by Resonance:

JEE Main 2021 Shifts | Physics | Chemistry | Maths |
---|---|---|---|

24 Feb – Shift 1 | Download PDF | Download PDF | Download PDF |

24 Feb – Shift 2 | Download PDF | Download PDF | Download PDF |

### JEE Main 2021 Answer Key by Reliable Kota

From the table below candidates can download the JEE Main 2021 answer key, solutions, and questions by the experts of Reliable Kota from the table below.

JEE Main 2021 Shifts | Physics | Chemistry | Maths |
---|---|---|---|

24 Feb – Shift 1 | Download PDF | Download PDF | Download PDF |

24 Feb – Shift 2 | Download PDF | Download PDF | Download PDF |

### JEE Main 2021 Answer Key with Question Paper

### JEE Main 24 Feb 2021 Shift 2 Question Paper with Answer Key – Paper 1 (BE / B.Tech)

**Ques. **Find the area enclosed by the parabolas y = 5x^{2} and y = 2x^{2} + 9.

**Ques. **Given y = (x) such that x dy/dx + y = bx^{4} then find b**Ans. **10

**Ques. **Find the point on y = x^{2} + 4 which is at the shortest distance from the line y = 4x -4**Ans. **2,8

**Ques. **

**Ans. **Correct Option is [C]

**Ques. **

**Ans. **-1 -√2 -√3

**Ques. **If A is symmetric matrix and B is skew matrix of order 3×3, then consider (A^{2}B^{2} – B^{2}A^{2}) X = 0, where X is matrix of unknown variables of 3×1 and O is a null matrix of 3×1, then system of linear equation is**Ans.** ∞ solution

**Ques. **

**Ans.** 2

**Ques. **The variance of 10 natural numbers 1, 1, 1, ….., k is less than 10. Find the maximum value of k. **Ans**. 6

**Ques. ** An airplane at point A gives an angle of elevation 60^{o} and after 20 seconds when the airplane is moving with speed 432 km/hr and making an angle of 30^{o}. Then find the height of the airplane in meters. **Ans**. 1200√3

**Ques. **Evaluate tan (1/4 sin^{-1} )√63/8) **Ans. **4-√7/3

**Ques. **A rod of mass M of length L is bent in the form of hexagon. Then MOI about axis passing through geometric centre & perpendicular to plane of body will be?**Ans**. ML^{2}/216

**Ques.** The Broglie wavelength of proton & particle are equal to the ratio of their velocities is**Ans. **1:4

**Ques. **The weight of a person on a pole is 48 N then the weight on equator is?**Ans.** 47.84

**Ques. **Two electrons fixed at a separation of 2d from each other. A proton is placed at the midpoint and is displaced slightly in a direction perpendicular to the line joining two electrons. Find the frequency of oscillation of proton.

**Ques. **In the Young’s double slit experiment. What will happen if the red light is replaced by violet light?**Ans. **λ↓ β ↓

**Ques. **Maximum frequency in transition**Ans. **n = 2 —->1

**Ques. **X-ray tube operation in 1.24 mili volts. What is the wavelength produced of photon?**Ans. **-1nm

**Ques. **Two electrons were placed 2d distance apart, a proton was placed at the middle and shifted x<<d , the system performs shm , then the frequency of oscillation will be?

**Ques. **A travelling wave represented by

**Ques. **A particle O at x-axis and damping force F = x^{2} is constant acting on it before comes to rest. The distance travelled by particle. **Ans**. (3mu^{2} / 2a)^{1/3} = x

**Ques. **Where will the center of mass of the disc shift when a cavity of radius R/2 is cut from it?** **

**Ques. **12NC charge over 6cm of a 12 cm x 12 cm square. What is flux through the square?**Ans. **22.59 x 10^{4} T-m^{2}

**Ques. **Length 1m can be measured up to 0.01m, time period 1.955, 0.01 time accuracy. What is the erroring?**Ans. **Around 2%

**Ques. **What happens in domain of ferromagentic material if placed in external magnetic field. **Ans. **May increase of decrease in size

**Ques. **Two carts are moving toward each other with speed 7.2kmph. Each blow horn 676 Hz. Velocity of air is 340> What is beat heard by each. **Ans.** 8

**Ques. **Two masses 1 kg and 2kg moving with equal momentum. Find the ratio of K.E. **Ans. **k1:k2 = 2:1

**Ques. **Half life of a reaction is 3.33 hrs. Sucrose —-> glucose + fructose after 9 hrs fraction of sucrose left is f. Then calculate the value of log (1/f). **Ans. **0.9

**Ques. **If a compound CxHy required 6 times volume of O2 then its self and produced 4 times volume of CO2 then find y. **Ans. **8

**Ques. **

**Ans. **D,C, B, A

**Ques. **

**Ans. **Correct option is [B]

**Ques. **Statement 1: Hydrogen is most abundant in universe but not in earth troposphere.

Statement 2: Hydrogen is lightest element**Ans.** Both statement are correct and second is correct explanation for statement-1

**Ques. **NO2 forms dimer but ClO2 does not. Why?**Ans. **in ClO2, unshared electron present in sp3orbital

**Ques. **

**Ans. **Correct option is [B]

**Ques. **What is the correct order of density for Zn, Fe, Co, Cu, Cr**Ans. **Cu> Co> Fe> Cr> Zn

**Ques. **In Buna S, S is for**Ans. **Styrene

**Ques. **

**Ques.** Match the following columns

A | B |
---|---|

a. Al | p. Siderite |

b. Zn | q. Malachite |

c. Fe | r. Calamine |

d. Cu | s. Bauxite |

**Ans. **a—>s, b—–>r, c—->p, d—->q

**Ques. **Which of the following has the highest M.P?**Ans. **MgO

**Ques. **Which of the following is used in blood clotting?**Ans.** FeCl3

**Ques. **The general solution of the differential equation dy/dx + sin (x+y/2) = sin (x-y/2) is

**Ques. **Electric flux crossing the surface which enclose a charge Q will be maximum if surface S is **Ans. **Sam in spherical, cube and cylindrical

**Ques.** When an impurity is dropped into an intrinsic semi-conductor , the conductivity of the semi-conductor **Ans. **increases

**Ques. **In contact process the impurities of aresenic are removed by ______**Ans. **Fe(OH)3

**Ques. **The tendency to form complex is maximum in _______**Ans.** Transition element

**Ques. **What is the shape of I3- ion?**Ans.** Linear

### JEE Main 24 Feb 2021 Shift 1 Question Paper with Answer Key – Paper 1 (BE / B.Tech)

**Ques. **In the shown circuit the following battery is of EMF 4 and internal resistance 8 Ω. Find the potential difference between points x and y shown in the circuit.

**Ans.** V_{x} – V_{y} = 2.4V

**Ques. **A horizontal spring block system (mass m_{2} spring constant k) is oscillating on a smooth surface with amplitude A. If at mean position an identical block is kept on it so that they move together after what is the new amplitude?**Ans.** A / √2

**Ques. **Find the minimum force F_{0} that should be applied to the block of mass m = 0.5 kg so that the block stays in equilibrium with the rough vertical wall having friction coefficient μ = 0.2 (take g = 10 m/s^{2}).**Ans.** 25 N

**Ques. **How does the energy of photon change as the corresponding wavelength increases?**Ans. **Decreases

**Ques. **Monomer of Buna-S and Nylon -6**Ans. **

**Ques. **Anaerobic respiration causes?**Ans. ** Greenhouse effect

**Ques. **What is the coordination number of atoms in BCC?**Ans.** 8

**Ques. **Compare the first ionization energy of Mg, Al, Si, P, S.**Ans. **Al < Mg < Si , S < P

**Ques. **Which of the following ore is concentrated using group 1 cyanide?**Ans. **Sphalerite

**Ques. **Why nitration of aniline gives 47% meta product?**Ans.** Due to formation of anilium ion.

**Ques. **Find the product.

**Ans.**

**Ques. **Cu, Zn, Cr, Co – Which has +ve reduction potential values for M^{2+} _{(aq)} / M _{(s)}**Ans. **Cu

**Ques. **Find the time period of reaction for 40% completion of reaction. Rate constant is 25 x 10^{-4} s^{-1}.**Ans. **202

**Ques. **

**Ans. **

**Ques. **Helical structure of DNA / protein is formed by which bond?**Ans. **Hydrogen bonding

**Ques. **What is the bond angle of H_{2}O?**Ans. **104.5°

**Ques. **Substance is given with molar mass 90 g per mole. The weight given is 4.5 g. Volume of solution is 250 ml. Find molarity.**Ans. **0.2 mol / litre

**Ques. **Which of the following oxides of nitrogen converts to another oxide on heating?**Ans. **N_{2}O_{4}

**Ques. **

**Ans. **75

**Ques. **

**Ans. **1

**Ques.** A die is rolled n times. If the probability of getting odd number 2 times is equal to the probability of getting even number 3 times. Find the probability of getting off number odd times.**Ans. **1/2

**Ques. **

**Ans. **f(x) is continuous ∀ x ∈ R

**Ques. **A man is walking on a straight line whose arithmetic mean of reciprocal intercepts on axes is 1/4. There are 3 marbles at A (1, 2), B (2, 2), C (4, 4). Then which marble lies in his path?

**Ques. **

**Ans. **(1, 3)

**Ques. **The distance of the point (1, 1, 9) from the point of intersection of the line (x-3) / 1 = (y-4) / 2 = (z-5)/ 2 and plane x +y + z = 1 is?**Ans. **√38

**Ques. **There are two poles and one is three times the other and they are 150 m apart and a man from the mid-point found elevation angles complementary. Find the height of the small pole.**Ans. **25 √3

**Ques. **a_{1}, a_{2}, … a_{10} are in GP. a_{7 }/ a_{5} = 25. Find a_{10} / a_{8}.**Ans.** 25

**Ques. **Which of the following is tautology?**Ans. **(A ∩ (A → B)) → B

**Ques. **The population p(t) at time t of a certain mouse species satisfies the differential equation dp (t) / dt = 0.5 p(t) – 450. If p (0) = 850, then the time at which the population becomes zero is?**Ans, **2 log18

**Ques. **

**Ques. **

**Ans. ** 2/3

**Ques. **If Z + α|Z-1| + 2i = 0, then find the sum of maximum and minimum values of α, (α ∈ R)**Ans. **α ∈ (± 1/**√**5)

**Ques. **

**Ans.** 5

**Ques. **

**Ans.** 5

**Ques. **p, q > 0 and p + q = 2 and p^{4} + q^{4} = 272. Find the equation whose roots are p and q. **Ans. **x^{2} – 2x + 16 = 0

**Ques. **Find the area of the region inside the circle x^{2} + y^{2} = 36 and outside the parabola y^{2} = 9x.

**Ques. **If the tangent to the curve y = x^{3} at the point P (t, t^{3}) meets the curve again at Q, then the co-ordinate of the point which divides PQ internally in the ratio 1:2

**Ques. **From 6 Indians and 8 Americans, a committee is formed which includes at least 2 Indians and double the number of Americans as Indians. Find number of way is **Ans. **1625

**Ques.**f(x) = 4x^{3} – 3x^{2} / 2 – 2sinx + (2x-1) cosx:**Ans. **Increases in [1/2, ∞]

**Ques. **If R —–> R is a function defined by (x) = [x – 1] cos (2x-1 / 2)⊼ where [.] —>gif**Ans. **Continuous for every real x

**Ques. **If the imaginary part of expression z-1 / e^{iθ} + e^{iθ} / z-1 is zero, the locus of z is

**Ques. **The tangent to the curve x = a (0 – sinθ), y = a(1+cosθ) at the point θ = (2k+1)x, k ∊ I are parallel to **Ans. **y = 0

**Ques. **Compare the Ionisation Energy of SC, RI, V, Cr, Mn…

**Ques. **What is the composition of gun metal?**Ans. **88 percent copper, 10 percent tin, and 2 percent zinc

**Ques. **The solution of differential equation xdy – ydx = √x^{2} + y^{2} dx is **Ans. **y + √x^{2} + y^{2} = cx^{2}

**Ques. **

**Ans.** Correct option is [B]

**Ques. **The equations of AM and EC are given, then find the percent of modulation.

**Ques. **The ratio of effusion does not depend on _____**Ans. **Size of molecule

**Ques. **An ore of Tin containing FeCrO_{4} is concentrated by _____**Ans**. Magnetic separator

**Ques. **A cube is given and it has -q charge in one corner and +q charges in all the remaining 7 corners. Find the electric field inside the cube.

**Ques. **The non-existence of PbI4 is due to ________**Ans.** Small size of Pb ion and large size of I ion. Highly reduced power of I ion.

**Ques. **Block m has amplitude A. If another mass of m is added what will be the new amplitude?

**Ques. ** A body cools down from 100C to 90C in 20 minutes. It will cool down from 110C to 100C in _____**Ans. **Less than 20 minute

**Ques. **A P and V graph was given, find the work done.

**Ques. **If there is degradation of vegetation, then what effect is caused in the environment from gas released?

**Ques. **An astronaut has left the international space station to test a new space scooter. His partner measures the fall velocity changes which take place in 10s interval. Find the magnitude and direction of average acceleration at the beginning of 10 sec interval, the astronaut is moving towards the x-axis in 10m/sec and at the end is 10 sec. He is moving towards the -ve axis at 5m/sec. **Ans.** 1.5 m/sex, -ve x-axis

**Ques. **What will be the energy if you increase lambda

**Ques. **If a dice is rolled n times. If the probability of getting even number and odd number is equal then find n.

**Ques. **Two capacitors are given. Find the series and parallel resistant and their ratio.

**Ques. **Find the work done by the cylcin process.

**Ques. **Calculate the ionization energy of all third period elements.

### How to Calculate Marks Using JEE Main 24 Feb 2021 Question Paper with Answer Key?

The candidates can check the steps below to know how they can use the answer key for JEE Main 2021 to calculate their probable scores in the exam:

**Step 1** – First of all, make sure the answer key is downloaded / opened for the correct question paper.

**Step 2** – Match the question and answer from the answer key. Then use the marking scheme to calcukate the scores.

**Step 3** – If the response matches, then add (+) 4 marks. However, if the answer is incorrect then deduct marks as instructed below.

Type of Question | Negative Marking per Qs. |
---|---|

MCQ | -1 |

NVT | – 0 |

**Step 5**: Candidates need to repeat this process for all the questions. In the end, add all the marks for the correct and incorrect answers, separately. Lastly, deduct the sum of incorrect answers from that of correct answers. Candidates will know their probable score.

**Candidates can also use the formula below:**

JEE Main 2020 raw score = Sum of Correct Answers – Sum of Incorrect Answers

### How to Download JEE Main 24 Feb 2021 Question Paper with Answer Key?

Candidates must ensure that they have a strong internet connection and a compatible browser before downloading their answer key for JEE Main 2020.

**STEP 1:** The very first step is to click on the above mentioned link.

**STEP 2**: Next, the candidate needs to locate the link of the answer key at the homepage of NTA . Locate it and click it.

**STEP 3: **Thereafter, enter the candidate login with the help of application form number and password.

**STEP 4:** At last, under the login candidates can check the question paper, response sheet and answer key for JEE Main 2021.

### JEE Main 24 Feb 2021 Question Paper

On the day of the exam, memory based JEE Main 2021 question paper is released by different coaching centres like Akaash, Allen, Resonance and Motion IIT. It is based on the questions and answers remembered by the students who appear for JEE Main exam.

However, a few days later, answer key for JEE Mains 2020 is officially released by National Testing Agency. The official question paper has the responses of the candidates too. It i released for all shifts and days in which JEE Main 2021 is being held.

### JEE Main 2021 Result

NTA will declare JEE Main 2021 result in a few days. The result of JEE Main will be announced at jeemain.nta.nic.in. The raw scores calculated via JEE Main 2021 official answer key are converted into NTA scores. These scores are calculated shift wise for physics, chemistry, maths, and overall.

On the basis of NTA score, JEE Main 2021 all India rank is decided. If a candidate has appeared for all the attempts of JEE Main then the best score of all the 4 attempts will be used to prepare the AIR. The better the NTA score, the higher is the rank of JEE Main.

### Previous Years Cut Off

NTA releases the cut off score for JEE Main entrance exam along with the declaration of the result. JEE Main cut off is the minimum score required by the candidates to qualify for JEE Advanced. It is to be noted that there is no passing or qualifying marks in JEE Main which means that all candidates who appear for the exam are given ranks for admission in NITS, IIITs, CFTIs.

**Candidates can check the past year JEE Main cut off from the table below.**

Category | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
---|---|---|---|---|---|---|

Open | 90.3765335 | 89.7548849 | 74 | 81 | 100 | 105 |

Gen EWS | 70.2435518 | 78.2174869 | – | – | – | – |

OBC NCL | 72.8887969 | 74.3166557 | 45 | 49 | 70 | 70 |

SC | 50.1760245 | 54.0128155 | 29 | 32 | 52 | 50 |

ST | 39.0696101 | 44.3345172 | 24 | 27 | 48 | 44 |

PWD | 0.0618524 | 0.11371730 | -35 | 01 | – | – |

### About JEE Main 2021

National Testing Agency i.e NTA conducts the JEE Main 2021 in computer based mode. The exam is of 3 hours and questions asked are of MCQ and numerical answer type. It is conducted in shifts and paper are categorised into B.Tech, B.Arch, and B.Plan. The authority allots 4 marks for each correct answer and 1 mark is deducted for negative answers. Qualified candidates then have to register and exercise options through the JOSAA counselling 2021.

## FAQs on JEE Main 24 Feb 2021 Question Paper with Answer Key

**By when will NTA release answer key for JEE Mains 2021?**

NTA is expected to released JEE Main 2021 answer key in 2-3 days after the exam.

**How to get answer key of JEE 2021 exam?**

Candidates can download the JEE Main answer key from jeemain.nta.nic.in. To download it, candidates need to enter application number and password / date of birth.

**What is the official website to get information about JEE Main 2021?**The official website is jeemain.nta.nic.in.

**How many times a student can appear in one year?**A candidate can appear a maximum of 4 times in 2021 in JEE Main exam.

*Official Website: jeemain.nta.nic.in*

Sir be/BTEC JEE main question papers show sir in 2021?