JEE Main 2021 Question Paper & Answers
The official JEE Main 2021 question papers, with the official answer key. Attempt as a real timed exam (with negative marking) or switch to practice mode for instant per-question answers and explanations.
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Official PYQ
JEE Main 2021 - August 26 Shift 2
180 Mins 296 Marks
74Questions
296Max Marks
Sample questions from JEE Main 2021 - August 26 Shift 2
1SECTION-A The temperature of equal masses of three different liquids x,y and z are 10ºC, 20ºC and 30ºC respectively. The temperature of mixture when x is mixed with y is 16ºC and that when y is mixed with z is 26ºC. The temperature of mixture when x and z are mixed will be :
- A) 28.32º C
- B) 25.62º C
- C) 23.84ºC
- D) 20.28ºC
Answer: C
2
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Answer: B
3
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Answer: C
4
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Answer: C
5
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Answer: D
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Official PYQ
JEE Main 2021 - February 24 Shift 1
180 Mins 300 Marks
75Questions
300Max Marks
Sample questions from JEE Main 2021 - February 24 Shift 1
1
- A)
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- D)
Answer: A
2
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Answer: A
3
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Answer: D
4Two equal capacitors are first connected in series and then in parallel. The ratio of the equivalent capacities capacities in the two cases will be -
- A) 2 : 1
- B) 1 : 4
- C) 4 : 1
- D) 1 : 2
Answer: B
5
- A)
- B)
- C)
- D)
Answer: C
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Official PYQ
JEE Main 2021 - February 25 Shift 2
180 Mins 300 Marks
75Questions
300Max Marks
Sample questions from JEE Main 2021 - February 25 Shift 2
1
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Answer: B
2
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Answer: D
3
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Answer: A
4The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from to state is:
- A) 194.8 nm
- B) 490.7 nm
- C) 913.3 nm
- D) 121.8 nm
Answer: D
5In a ferromagnetic material, below the curie temperature, a domain is defined as:
- A) a macroscopic region with consecutive magnetic diploes oriented in opposite direction.
- B) a macroscopic region with zero magnetization.
- C) a macroscopic region with saturation magnetization.
- D) a macroscopic region with randomly oriented magnetic dipoles.
Answer: C
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Official PYQ
JEE Main 2021 - February 26 Shift 1
180 Mins 300 Marks
75Questions
300Max Marks
Sample questions from JEE Main 2021 - February 26 Shift 1
1If and are the wavelengths of the third member of the Lyman series and the first member of the Paschen series respectively, then the value of is:
- A) 1:3
- B) 1:9
- C) 7:135
- D) 7:108
Answer: C
2The temperature at the junction of two insulating sheets, having thermal resistances and , as well as top and bottom temperatures and respectively, is given by:
- A)
- B)
- C)
- D)
Answer: A
3In a Young's double slit experiment, two slits are separated by 2 mm and the screen is placed one metre away. When light of wavelength 500 nm is used, the fringe separation will be:
- A) 0.75 mm
- B) 0.50 mm
- C) 1 mm
- D) 0.25 mm
Answer: D
4Given below are two statements, one labelled as Assertion A and the other labelled as Reason R.
Assertion A: An electron microscope can achieve better resolving power than an optical microscope.
Reason R: The de Broglie wavelength of the electrons emitted from an electron gun is much less than the wavelength of visible light.
Choose the correct answer:
- A) A is true but R is false.
- B) Both A and R are true but R is NOT the correct explanation of A.
- C) Both A and R are true and R is the correct explanation of A.
- D) A is false but R is true.
Answer: C
5Four identical solid spheres, each of mass and radius , are placed with their centres on the four corners of a square of side . The moment of inertia of the system about one side of the square, where the axis of rotation is parallel to the plane of the square, is:
- A)
- B)
- C)
- D)
Answer: D
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Official PYQ
JEE Main 2021 - February 26 Shift 2
180 Mins 300 Marks
75Questions
300Max Marks
Sample questions from JEE Main 2021 - February 26 Shift 2
1A tuning fork A of unknown frequency produces with a fork of known frequency 340 HZ. When fork A filed, the beat frequency decreases to . What is the frequency of fork A?
- A) 342 Hz
- B) 335 Hz
- C) 338 Hz
- D) 345 Hz
Answer: B
2
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Answer: A
3A cord is wound round the circumference of wheel of radius r. The axis of the wheel is horizontal and the moment of inertia about it is I. A weight mg is attached to the cord at the end. The weight falls from rest. After falling through a distance ‘h’, the square of angular velocity of wheel will be:
- A)
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- D)
Answer: D
4
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Answer: D
5
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Answer: D
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Official PYQ
JEE Main 2021 - July 27 Shift 2
180 Mins 300 Marks
75Questions
300Max Marks
Sample questions from JEE Main 2021 - July 27 Shift 2
1SECTION-A An electron and proton are separated by a large distance. The electron starts approaching the proton with energy 3 eV. The proton captures the electrons and forms a hydrogen atom in second excited state. The resulting photon is incident on a photosensitive metal of threshold wavelength 4000 Å. What is the maximum kinetic energy of the emitted photoelectron?
- A) 7.61 eV
- B) 1.41 eV
- C) 3.3 eV
- D) No photoelectron would be emitted
Answer: B
2
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Answer: B
3
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Answer: C
4
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Answer: B
5
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Answer: A
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