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Friday, 9 October

JEE Main Maths · Vector Algebra

Dot Product in JEE Main

Dot Product (Maths, Vector Algebra) came 15 times in 13 of the 42 JEE Main shifts Lumi analysed, across 12 distinct ideas. 9 of them came in 2024–26; it was last asked in 2026.

Questions
15
in 13 shifts
Ideas asked
12
2 asked more than once
Numerical answer
3
20% of its questions
Pattern
Asked most years
last asked 2026
Questions each year
0240’172’201’213’220’233’243’253’26

In the shifts Lumi analysed for each year.

Difficulty and format
Easy 3Medium 11Hard 1

Format

  • Single correct12 Q
  • Numerical value3 Q

Every question

All 15 Dot Product questions

Newest first, each with its options and official answer.

  1. 2 Apr 2026, Shift 1 · Q14If a⃗\vec a and b⃗\vec b are two vectors such that ∣a⃗∣=2|\vec a|=2 and ∣b⃗∣=3|\vec b|=3, then the maximum value of…HardSingle correct
  2. 2 Apr 2026, Shift 2 · Q14Let the vectors a⃗=−i^+j^+3k^\vec{a} = -\hat{i} + \hat{j} + 3\hat{k} and b⃗=i^+3j^+k^\vec{b} = \hat{i} + 3\hat{j} + \hat{k}. For some…MediumSingle correct
  3. 2 Apr 2026, Shift 2 · Q16Two adjacent sides of a parallelogram PQRSPQRS are given by PQ⃗=j^+k^\vec{PQ} = \hat{j} + \hat{k} and PS⃗=i^−j^\vec{PS} = \hat{i} - \hat{j}. If the side…MediumSingle correct
  4. 2 Apr 2025, Shift 1 · Q11If a⃗\vec{a} is a nonzero vector such that its projections on the vectors 2i^−j^+2k^2\hat{i}-\hat{j}+2\hat{k}, i^+2j^−2k^\hat{i}+2\hat{j}-2\hat{k} and…MediumSingle correct
  5. 7 Apr 2025, Shift 2 · Q15Let a⃗\vec{a} and b⃗\vec{b} be the vectors of the same magnitude such that…MediumSingle correct
  6. 8 Apr 2025, Shift 2 · Q14Let a⃗=i^+2j^+k^\vec{a} = \hat{i} + 2\hat{j} + \hat{k} and b⃗=2i^+j^−k^\vec{b} = 2\hat{i} + \hat{j} - \hat{k}. Let c^\hat{c} be a unit vector in the plane of…MediumSingle correct
  7. 8 Apr 2024, Shift 1 · Q18The set of all α\alpha, for which the vectors a⃗=αti^+6j^−3k^\vec{a}=\alpha t\hat{i}+6\hat{j}-3\hat{k} and…MediumSingle correct
  8. 29 Jan 2024, Shift 1 · Q18Let O be the origin and the position vectors of A and B be 2i^+2j^+k^2\hat{i}+2\hat{j}+\hat{k} and 2i^+4j^+4k^2\hat{i}+4\hat{j}+4\hat{k} respectively. If…MediumSingle correct
  9. 30 Jan 2024, Shift 2 · Q18Let a⃗\vec{a} and b⃗\vec{b} be two vectors such that ∣b⃗∣=1|\vec{b}| = 1 and ∣b⃗×a⃗∣=2|\vec{b} \times \vec{a}| = 2. Then…EasySingle correct
  10. 28 Jul 2022, Shift 1 · Q6Let a vector a⃗\vec{a} has magnitude 9. Let a vector b⃗\vec{b} be such that for every (x,y)∈R×R−{(0,0)}(x,y)\in\mathbf{R}\times\mathbf{R}-\{(0,0)\}, the…MediumSingle correct
  11. 28 Jul 2022, Shift 1 · Q22Let P(−2,−1,1)P(-2,-1,1) and Q(5617,4317,11117)Q\left(\frac{56}{17},\frac{43}{17},\frac{111}{17}\right) be the vertices of the rhombus PRQS. If the direction…MediumNumerical value
  12. 29 Jun 2022, Shift 1 · Q5Let a⃗=αi^+3j^−k^\vec{a} = \alpha\hat{i} + 3\hat{j} - \hat{k}, b⃗=3i^−βj^+4k^\vec{b} = 3\hat{i} - \beta\hat{j} + 4\hat{k} and…MediumSingle correct
  13. 18 Mar 2021, Shift 1 · Q80A vector a⃗\vec{a} has components 3p and 1 with respect to a rectangular cartesian system. This system is rotated through a certain angle…MediumSingle correct
  14. 2 Sep 2020, Shift 1 · Q75Let a⃗\vec{a}, b⃗\vec{b} and c⃗\vec{c} be three unit vectors such that ∣a⃗−b⃗∣2+∣a⃗−c⃗∣2=8|\vec{a}-\vec{b}|^{2}+|\vec{a}-\vec{c}|^{2}=8. Then…EasyNumerical value
  15. 6 Sep 2020, Shift 2 · Q74If x⃗\vec{x} and y⃗\vec{y} be two non-zero vectors such that ∣x⃗+y⃗∣=∣x⃗∣|\vec{x}+\vec{y}|=|\vec{x}| and 2x⃗+λy⃗2\vec{x}+\lambda\vec{y} is perpendicular…EasyNumerical value