Q61.If â and b̂ are unit vectors inclined at an angle θ, then the value of () ˆ 1 a - b 2 is
Correct answer: sin θ/2
Q62.B×C,C× A,A×B is
Correct answer: 2/ABC
Q63.Let a 4i 5j k = + − b i 4j 5k = − + c 3i j k = + − Then a vector d which is perpendicular to both a and b and for which d. c = 21 is
Correct answer: () 7 i j k − −
Q64.Which of the following is/ are true?
Correct answer: Both
Q65.If 1, 2, 3 V V V are three non-zero vectors such that 1 2 3 2 3 1 V V V,V V V × = × = × = × = × = × = × = × = then
Correct answer: 1 3 V V =
Q66.If A B C D × = × × = × × = × × = × and A C B D × = × × = × × = × × = ×, then vectors A D − − and B C − − are
Correct answer: parallel
Q67.The value of ((())) (((()))) c a a b × × × × × × × × × × × × is
Correct answer: abc a
Q68.If 2 ˆ ˆ ˆ F x yi xzj 2yzk = + + = + + = + + = + + then the value of div curl F is
Correct answer: 0
Q69.If 2 2 a b a.b 144 × + = × + = × + = × + = and a 4 =, then b is equal to-
Correct answer: 3
EnglishSECTION B PGT TIER-I 31.11.2014
Q70.If ˆ ˆ i, jand k are unit vectors. The value of i. j k j. i k k. i j is–
Correct answer: 1
EnglishSECTION B PGT TIER-I 31.11.2014
Q71.If is the angle between any two vectors a and b, then a.b a b when is equal to–
Correct answer: π/4
EnglishJDD-75-PGT TIER II-X-15 28.06.2015
Q72.lf a and b are two unit vectres inclined at an angle, 3 π then the value of a b + + is–
Correct answer: >1
EnglishJDD-75-PGT TIER II-X-15 28.06.2015
Q73.The area of the parallelogram whose adjacent sides are ˆ ˆ i k + + and ˆ ˆ ˆ 2i j k + + + + is–
Correct answer: 3
Q74.If the angle between the vectors a and b is 1200 and their magnitudes are 2 and 3 respectively, then a b ⋅ ⋅ is equal to:
Correct answer: 3
Q75.Let ˆ ˆ a i j = + = + and ˆ ˆ b 2j k = − = − then what will be point of intersection of the lines r a b a × = × × = × × = × × = × and r b a b × = × × = × × = × × = ×?
Correct answer: (1, 3, -1)
Q76.The magnitudes of the vectors a,b,c are 3, 4, 5 respectively. If the vectors a,b,c are respectively perpendicular to the victors b c, + c a + +, a b + + then the magnitude of a b c + + will be:
Correct answer: 5 2
Q77.If ˆ ˆ ˆ ˆ ˆ ˆ a 2i 3j 6k,b 3i 6j 2k = + + = − + = + + = − + = + + = − + = + + = − + then a b × × is:
Correct answer: ˆ ˆ ˆ 42i 14j 21k + −
Q78.Finding the angle between the vectors ˆ ˆ 3i 4j + and ˆ ˆ ˆ i j k − + − + using vector multiplication:
Correct answer: 74 Sin 5 3 θ =
Q79.If ˆ ˆ ˆ a,b,c are unit vectors and ˆ ˆ ˆ a b c 0 + + = + + = + + = + + = then ˆ ˆ ˆ ˆ ˆ ˆ a b b c c a ⋅ + ⋅ + ⋅ ⋅ + ⋅ + ⋅ ⋅ + ⋅ + ⋅ ⋅ + ⋅ + ⋅ is?
Correct answer: −3/2
Q80.If vectors a and b are unit vectors and makes an angle of 600, then:
Correct answer: a b 1/+ >