Q01. If the vectors a, b and c form the sides BC, CA and AB respectively of a ∆ ∆ ∆ABC, then:
A a×b = b×c = c×a
B a b = b c = c a = 0 ⋅ ⋅ ⋅
C a×a + a×c + a×b = 0
D a b = b c = c a = 0 ⋅ ⋅ ⋅
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Correct answer: a×b = b×c = c×a
Q02. Let ˆ ˆ ˆ a = 3i + 2j+ 2k and ˆ ˆ ˆ 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:
A () ˆ ˆ ˆ 4 2i - 2j- k
B () ˆ ˆ ˆ 4 2i + 2j- k
C () ˆ ˆ ˆ 4 -2i - 2j+ k
D () ˆ ˆ ˆ 4 2i + 2j+ k
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Correct answer: () ˆ ˆ ˆ 4 2i - 2j- k
Q03. If a unit vector â makes angles π 3 with î, π 4 with ĵ and () θ 0, π ∈ with k̂, then value of θ is:
A 4/π
B 5 12 π
C 2 3 π
D 5 6 π
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Correct answer: 2 3 π
English Bihar (TRE 2.0)-2023
Q04. The value of () () a -b × a + b is
A 2 ( )/a×b
B (a2 - b2)
C ( )/a×b
D More than one of the above
E None of the above
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Correct answer: 2 ( )/a×b
English Bihar (TRE 2.0)-2023
Q05. Time period is a
A vector quantity
B scalar quantity
C Neither scalar nor vector quantity
D More than one of the above
E None of the above
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Correct answer: scalar quantity
Q06. If a,b,c are unit vectors, then 2 2 2 ˆ ˆ ˆ ˆ ˆ ˆ a b b c c a − + − + − does not exceed:
A 4
B 9
C 8
D 6
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Correct answer: 9
Q07. If a and b are unit vector, then correct statement is-
A a + b will never be a unit vector
B a + b is unit vector, if a is parallel to b
C a + b is unit vector, if a is perpendicular to b
D a + b is unit vector, if angle between a and b is 2 3 π
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Correct answer: a + b is unit vector, if angle between a and b is 2 3 π
Q08. If a, b and c are unit vectors such that a + b + c = 0, then the value of a. b + b. c + c.a is:
A 1
B 3/2
C - 3 2
D 0
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Correct answer: - 3 2
Q09. The value of () i j k j k i k i j × + + × + + × + is equal to:
A () 2 i j k + +
B 0
C 1
D i j k/+ +
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Correct answer: 0
Q10. For any vector a, the value of () () () 2 2 2 ˆ ˆ a i a j a k × + × + × is:
A 2/3a
B 2/a
C 2/2a
D 2/4a
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Correct answer: 2/2a
Q11. If () () () ˆ ˆ ˆ ˆ ˆ ˆ i i a j j a k k a m.a, × × + × × + × × = then m is equal to:
A 0
B –2
C 2
D 1
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Correct answer: –2
Q12. If a b c + = and a b c, + = then angle between a and b is:
A 0°
B 45°
C 90°
D 180°
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Correct answer: 0°
Q13. If | a | 4 | b | 5 and a. b 10 = then the value | a b | × is:
A 10 2
B 5
C 10 3
D 10
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Correct answer: 10 3
Q14. Vectors a i 2j 3k, b 2i 3j k, = − + = − + and c 3i j 2k, = − − are given. The value of a b c is:
A 14
B 28
C 24
D 20
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Correct answer: 14
Q15. Let a = (2 î – ĵ + k̂), b = (î + 2 ĵ – k̂) and c = (î + ĵ–2 k̂) be three vector. A vector in the plane of b and c whose projection on a is zero, will be
A – 2 î – ĵ + 5 k̂
B ĵ + k̂
C ĵ – k̂
D î + ĵ – k̂
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Correct answer: ĵ + k̂
Q16. A,BandC are unit vectors. A is perpendicular to both B and C and angle between B and C is 30º. Then vector A is -
A (B C)/± ×
B 1 (B C) 2 ± ×
C 2(B C)/± ×
D 1 (B C) 3 ± ×
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Correct answer: 2(B C)/± ×
Q17. a;b;c are unit vectors b and c are non collinear vector. If a × (2b ×c) =b, then angle between a and b is -
A 90º
B 60º
C 45º
D 0º
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Correct answer: 90º
Q18. The midpoints of sides AB and AC of a triangle ABC are points D and E, respectively, then resultant of forces represented by BE and DC in magnitude and direction is represented by -
A 1 BC 2
B 2 BC 3
C 3 BA 2
D 3 BC 2
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Correct answer: 3 BC 2
Q19. If additive inverse vector of vector of vector pi + 2j – 3k is the vector (ab i + b j + pk), then which of the following is true (a>0)?
A p = 9, b = 4, a = 3/2
B p = 9, b = 4, a = 81/4
C p = 3, b = 4, a = 81/2
D p = 9, b = 4, a = 9/2
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Correct answer: p = 9, b = 4, a = 81/4
Q20. Let − x = 2i + j 2k and y = i + j.If z is a vector such that x.z = z, z x = 2 2 − − and the angle between x×y and z is 30° ° °, then the magnitude of the vector ()× x×y z is _________
A 3/2
B 3/2
C 1/2
D 3 2/2
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Correct answer: 3/2