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JEE Main Math Vectors Questions Answer Keys Solutions

Welcome to AMBiPi (Read as: एम्बीपाई) (Amans Maths Blogs). JEE Mains and JEE Advanced exams are the engineering entrance exams for taking admission in IITs, NITs and other engineering colleges. In this article, you will get JEE Main Math Vectors Questions Answer Keys Solutions.

JEE Mains Mathematics Vectors Questions Bank

JEE Vector Questions No:91

Let α = (λ – 2) a + b and β = (4λ – 2) a + 3b be two given vectors where vectors a and b are non-collinear. The value of λ for which vectors α and β are collinear, is

[2019]

Option A: -4

Option B: -3

Option C: 4

Option D: 3

Show/Hide Answer Key

Option A: -4

JEE Main Vector Questions No: 92

Let √3i + j, i + √3j and βi + (1 – β)j respectively be the position vectors of the points A, B and C with respect to the origin O. If the distance of C from the bisector of the acute angle between OA and OB is 3 / √2 then the sum of all possible values of β is :

[2019]

Option A: 4

Option B: 3

Option C: 2

Option D: 1

Show/Hide Answer Key

Option D: 1

JEE Mathematics Vector Questions No: 93

Let a = i + 2j + 4k, b = i + ????j + 4k and c = 2î + 4j + (????² − 1)k be coplanar vectors. Then the non-zero vector a × c is

[2019]

Option A: -10i – 5j

Option B: -14i – 5j

Option C-14i + 5j

Option D: -10i + 5j

Show/Hide Answer Key

Option D: -10i + 5j

JEE Mathematics Vector Questions No: 94

The sum of the distinct real values of μ, for which the vectors, µi + j + k, i + µj + k, i + j + µk, are co-planar is

[2019]

Option A: -1

Option B: 0

Option C: 1

Option D: 2

Show/Hide Answer Key

Option A: -1

Vector JEE Questions No: 95

If a unit vector a makes angles π/3 with i, (n/4) with j and θ ∈ (0, π) with k, then a value of θ, is:

[2019]

Option A: (5π / 6)

Option B: (π / 4)

Option C: (5π / 12)

Option D: (2π / 3)

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Option D: (2π / 3)

Vector JEE Main Questions No: 96

Let α ∈ R and the three vectors a = αi + j + 3k, b = 2i + j – αk and c = αî – 2j + 3k. Then the set S = (α: a, b and c are coplanar)

[2019]

Option A: is singleton

Option B: is empty

Option C: contains exactly two positive numbers

Option D: contains exactly two numbers only one of which is positive

Show/Hide Answer Key

Option B: is empty

JEE Main Math Vector Questions No: 97

If the volume of parallelopiped formed by the vectors i + λj + k, j + λk and λi + k is minimum, then λ is equal to:

[2019]

Option A: (-1 / √3)

Option B: (1 / √3)

Option C: √3

Option D: -√3

Show/Hide Answer Key

Option B: (1 / √3)

JEE Main Math Vector Questions No: 98

Let a = 3i + 2j + 2k and b = i + 2j – 2k be two vectors. If a vector perpendicular to both the vectors a + b and a b has the magnitude 12 then one such vector is

[2019]

Option A: 4(2i + 2j + 2k)

Option B: 4(2i – 2j k)

Option C: 4(2i + 2j k)

Option D: 4(-2i – 2j + k)

Show/Hide Answer Key

Option B: 4(2i – 2j – k)

JEE Main Vector Questions No: 99

Let a = i – 2j + k and b = i j + k be two vectors. If c is a vector such that b × c = b × a and c ∙ a = 0, then c ∙ b is equal to:

[2020]

Option A: (-3 / 2)

Option B: (1 / 2)

Option C: (-1 / 2)

Option D: -1

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Option C: (-1 / 2)

JEE Mathematics Vector Questions No: 100

Let ab and c be three vectors such that | a | = √3, | b | = 5, b ∙ c = 10 and the angle between b and c is (π/3). If b is perpendicular to the vector b × c  then | a × (b × c) is equal to

[2020]

Show/Hide Answer Key

Correct Ans: 30

JEE Main Math Vector Questions No: 101

If a = 2i + 3j + 2k, then the value of | i × (a × i) |² + | j × (a × j) |² + | k × (a × k) |² is equal to

[2020]

Show/Hide Answer Key

Correct Ans: 18

Vector JEE Questions No: 102

Let x0, be the point of local maxima of f(x) = a ∙ (b × c), where a = xi – 2j + 3k, b = -2i + xj k and c = 7î – 2j + xk. Then the value of a ∙ b + b ∙ c + c ∙ a at x = x0 is:

[2020]

Option A: -4

Option B: -30

Option C: 14

Option D: -22

Show/Hide Answer Key

Option D: -22

Vector JEE Main Questions No: 103

If the volume of a parallelepiped, whose coterminous edges are given by the vectors a = i + j + nk, b = 2i + 4j – nk and c = i + nj + 3k (n ≥ 0), is 158 cu. units, then:

[2020]

Option A: a ∙ c = 17

Option B: b ∙ c = 10

Option C: n = 7

Option D: n = 9 

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Option B: b ∙ c = 10

JEE Mathematics Vector Questions No: 104

A vector a = αi + 2j + βk (α, β ∈ R) lies in the plane of the vectors, b = i + j and c = i j + 4k. If a bisects the angle between b and c, then:  

[2020]

Option A: a i + 3 = 0

Option B: a i + 1 = 0

Option C: a k + 2 = 0

Option D: a k + 4 = 0

Show/Hide Answer Key

Option C: a ∙ k + 2 = 0

Vector JEE Questions No: 105

Let the volume of a parallelepiped whose coterminous edges are given by u = i + j + ????k, v = i + j + 3k and w = 2i + j + k be 1 cu. unit. If θ be the angle between the edges ū and w, then cosθ can be:

[2020]

Option A: (7 / 6√6)

Option B: (7 / 6√3)

Option C: (5 / 7)

Option D: (5 / 3√3)

Show/Hide Answer Key

Option B: (7 / 6√3)

Vector JEE Main Questions No: 106

 The projection of the line segment joining the points (1, -1, 3) and (2, -4, 11) on the line joining the points (-1, 2, 3) and (3, -2, 10) is

[2020]

Show/Hide Answer Key

Correct Ans: 8

JEE Main Math Vector Questions No: 107

Let a, b and c be three unit vectors such that | a b |² +| āc |² = 8. Then | ā + 2b |² + | ā + 2c |² is equal to

[2020]

Show/Hide Answer Key

Correct Ans: 2

JEE Main Math Vector Questions No: 108

Let the vectors a, b, c be such that | ā | = 2, | b | = 4 and | c | = 4. If the projection of b on a is equal to the projection of c on a and b is perpendicular to c, then the value of | a + b c | is

[2020]

Show/Hide Answer Key

Correct Ans: 6

JEE Main Math Vector Questions No: 109

If x and y be two non-zero vectors such that | x + y | = | x | and 2x + ????y is perpendicular to y, then the value of ???? is

[2020]

Show/Hide Answer Key

Correct Ans: 1

JEE Mains Vector Questions No: 110

If a and b are unit vectors, then the greatest value of √3 | a + b | + | a b | is

[2020] 

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Correct Ans: 4

JEE Main Math Vector Questions No: 111

If the vectors, p = (a + 1)i + aj + ak, q = ai + (a + 1)j +ak and r = ai + aj + (a + 1)k (a ∈ R) are coplanar and 3 (p ∙ q)² – λ | r × q |² = 0, then the value of λ is

[2020]

Show/Hide Answer Key

Correct Ans: 1

JEE Main Math Vector Questions No: 112

Let the position vectors of points ‘A’ and ‘B’ be i + j + k and 2i + j + 3k, respectively. A point ‘P’ divides the line segment AB internally in the ratio λ : 1 (λ > 0). If O is the region and OB × OP – 3 | OA × OP |2 = 6, then λ is equal to

[2020]

Show/Hide Answer Key

Correct Ans: 0.8

JEE Mains Math Vector Questions No: 113

Let a, b, c ∈ R be such that a² + b² + c² = 1. If acosθ – bcos(θ  + 2π/3) = c cos(θ + 4π/3)  where θ = (π/9), then the angle between the vectors ai + bj + ck and bi + cj + ak is

[2020]

Option A: (π / 2)

Option B: (2π / 3)

Option C: (π / 9)

Option D: 0

Show/Hide Answer Key

Option A: (π / 2)

JEE Main Math Vector Questions No: 114

If a and b are perpendicular, then a × (a × (a × (a × b) ) ) is equal to :

[2021]

Option A: a × b

Option B: 0

Option C: (1/2) | a |4 b

Option D: | a |4 b

Show/Hide Answer Key

Option D: | a |4 b

JEE Main Math Vector Questions No: 115

Let c be a vector perpendicular to the vectors a = i + j k and b = i + 2j + k. If c ∙ (i + j + 3k) = 8 then the value of c ∙ (a × b) is equal to

[2021]

Show/Hide Answer Key

Correct Ans: 28

JEE Main Math Vector Questions No: 116

Let a = i + 2j – 3k and b = 2i – 3j + 5k. If r × a = b × r, r ∙ (ai + 2j + k) = 3 and r ∙ (2i + 5j – αk) = 1 α ∈ R, then the value of α +| r |2 is equal to:

[2021]

Option A: 15

Option B: 13

Option C: 9

Option D: 11

Show/Hide Answer Key

Option A: 15

JEE Main Math Vector Questions No: 117

Let a = 2i – 3j + 4k and b = 7i + j – 6k. If r × a b × r, r (i + 2j+ k) = −3, then r (2i – 3j + k)

[2021]

Option A: 10

Option B: 13

Option C: 8

Option D: 12

Show/Hide Answer Key

Option D: 12

JEE Mains Math Vector Questions No: 118

Let a = i – αj + βk, b = 3i + βj – αk and c = – αi – 2j + k, where α and β are integers. If a ∙ b = -1 and b ∙ c = 10, then (a × b) c is equal to

[2021]

Show/Hide Answer Key

Correct Ans: 9

JEE Main Math Vector Questions No: 119

Let a = i + j + k and b = j k. If c is a vector such that a × c = b and a ∙ c = 3, then a ∙ (b × c) is equal to

[2021]

Option A: -2

Option B: -6

Option C: 6

Option D: 2

Show/Hide Answer Key

Option A: -2

JEE Vector Questions No:120

Let a = i + 5j + αk, b = i + 3j + βk and c = −i + 2j – 3k be three vectors such that, | b × c | = 5√3 and a is perpendicular to b. Then the greatest amongst the values of | a |² is

[2021]

Show/Hide Answer Key

Correct Ans: 90

JEE Main Mathematics Previous Year Questions with Solutions: Algebra
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JEE Main Previous Year Mathematics Questions Complex Numbers
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JEE Main Previous Year Mathematics Questions Sequence & Series
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JEE Main Previous Year Mathematics Questions Quadratic Equations
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JEE Main Previous Year Mathematics Questions Permutations & Combinations
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JEE Main Previous Year Mathematics Questions Binomial Theorems
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JEE Main Previous Year Mathematics Questions Determinants & Matrices
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JEE Main Mathematics Previous Year Questions with Solutions: Trigonometry
JEE Main Previous Year Mathematics Questions Trigonometry Ratios Identities
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JEE Main Previous Year Mathematics Questions Properties of Triangles
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JEE Main Previous Year Mathematics Questions Trigonometrical Equations
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JEE Main Previous Year Mathematics Questions Inverse Trigonometrical Functions
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JEE Main Mathematics Previous Year Questions with Solutions: Coordinate Geometry
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JEE Main Previous Year Mathematics Questions Parabola 
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JEE Main Previous Year Mathematics Questions Ellipse 
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JEE Main Previous Year Mathematics Questions Hyperbola 
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JEE Main Mathematics Previous Year Questions with Solutions: Differential Equations
JEE Main Previous Year Mathematics Questions Limit, Continuity & Differentiability 
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JEE Main Previous Year Mathematics Questions Differentiations 
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JEE Main Previous Year Mathematics Questions Definite Integrals 
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JEE Main Previous Year Mathematics Questions Area By Integration 
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JEE Main Mathematics Previous Year Questions with Solutions: Differential Equations
JEE Main Previous Year Mathematics Questions Differential Equations 
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JEE Main Mathematics Previous Year Questions with Solutions: Vector & 3D Geometry
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JEE Main Previous Year Mathematics Questions 3D Geometry 
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JEE Main Mathematics Previous Year Questions with Solutions: Statistics & Probability
JEE Main Previous Year Mathematics Questions Statistics 
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JEE Main Previous Year Mathematics Questions Probability 
| 1 to 30 | 31 to 60 | 61 to 95 |
JEE Main Mathematics Previous Year Questions with Solutions: Miscellaneous
JEE Main Previous Year Mathematics Questions Mathematical Induction 
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JEE Main Previous Year Mathematics Questions Mathematical Reasoning 
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AMAN RAJ
I am AMAN KUMAR VISHWAKARMA (in short you can say AMAN RAJ). I am Mathematics faculty for academic and competitive exams. For more details about me, kindly visit me on LinkedIn (Copy this URL and Search on Google): https://www.linkedin.com/in/ambipi/

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