Explore topic-wise MCQs in Joint Entrance Exam - Main (JEE Main).

This section includes 8666 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.

1651.

If \[\mathbf{a},\,\mathbf{b},\,\mathbf{c}\] are non-coplanar vectors and \[\lambda \] is a real number then \[[\lambda (\mathbf{a}+\mathbf{b})\,\,\,\,{{\lambda }^{2}}\mathbf{b}\,\,\,\,\,\lambda \mathbf{c}]=\left[ \mathbf{a}\,\,\mathbf{b}+\mathbf{c}\,\,\mathbf{b} \right]\] for       [AIEEE 2005]

A.             Exactly three values of \[\lambda \]     
B.             Exactly two values of \[\lambda \]
C.             Exactly one value of \[\lambda \]
D.             No value of \[\lambda \]
Answer» E.
1652.

If \[\mathbf{a}\] is perpendicular to \[\mathbf{b}\]and \[\mathbf{c},|\mathbf{a}|=2,|\mathbf{b}|=3\], \[|\mathbf{c}|=4\] and the angle between \[\mathbf{b}\] and \[\mathbf{c}\]is \[\frac{2\pi }{3}\], then \[[\mathbf{a}\ \mathbf{b}\ \mathbf{c}]\] is equal to                          [Kerala (Engg.) 2005]

A.             \[4\sqrt{3}\]
B.             \[6\sqrt{3}\]
C.             \[12\sqrt{3}\]
D.             \[18\sqrt{3}\]
E.             \[8\sqrt{3}\]
Answer» D.             \[18\sqrt{3}\]
1653.

If \[\mathbf{a}=\mathbf{i}+\mathbf{j}-\mathbf{k},\,\,\mathbf{b}=2\mathbf{i}+3\mathbf{j}+\mathbf{k}\] and \[\mathbf{c}=\mathbf{i}+\alpha \mathbf{j}\] are coplanar vectors, the value of \[\alpha \] is   [UPSEAT 2004]

A.             \[-\frac{4}{3}\]
B.             \[\frac{3}{4}\]
C.             \[\frac{4}{3}\]
D.             2
Answer» D.             2
1654.

Out of the following which one is not true        [Orissa JEE 2004]

A.             \[\mathbf{a}\,.\,(\mathbf{b}\times \mathbf{c})\]
B.             \[(\mathbf{b}\times \mathbf{c})\,.\,\mathbf{a}\]
C.             \[(\mathbf{a}\times \mathbf{b})\,.\,\mathbf{c}\]
D.             \[(\mathbf{a}.\mathbf{c})\,\times \,\mathbf{b}\]
Answer» E.
1655.

. If \[\mathbf{a}\,.\,\mathbf{b}=\mathbf{b}\,.\,\mathbf{c}=\mathbf{c}\,.\,\mathbf{a}=0\] then the value of  [a b c] is equal to                                        [Pb. CET 2000]

A.             1
B.             ? 1
C.             \[|\mathbf{a}||\mathbf{b}||\mathbf{c}|\]
D.             0
Answer» D.             0
1656.

Let \[\mathbf{a},\,\mathbf{b}\] and \[\mathbf{c}\] be three vectors. Then scalar triple product x is equal to                                     [UPSEAT 2004]

A.            
B.            
C.            
D.            
Answer» E.
1657.

If \[\mathbf{a},\,\,\mathbf{b},\,\,\mathbf{c}\] are non-coplanar vectors and l is a real number, then the vectors \[\mathbf{a}+2\mathbf{b}+3\mathbf{c},\,\lambda \,\mathbf{b}+4\mathbf{c}\] and \[(2\lambda -1)\mathbf{c}\] are non-coplanar for [AIEEE 2004]

A.             No value of l
B.             All except one value of l
C.             All except two values of l
D.             All values of l
Answer» E.
1658.

Vector coplanar with vectors i + j and j + k and parallel to the vector 2i ? 2j ? 4k, is                      [Roorkee 2000]

A.             i ? k
B.             i ? j ? 2k        
C.             i + j ? k
D.             3i + 3j ? 6k
Answer» C.             i + j ? k
1659.

The value of l for which the four points \[2\mathbf{i}+3\mathbf{j}-\mathbf{k},\] \[\mathbf{i}+2\mathbf{j}+3\mathbf{k}\], \[3\mathbf{i}+4\mathbf{j}-2\mathbf{k},\,\,\mathbf{i}-\lambda \mathbf{j}+6\mathbf{k}\] are coplanar                                     [MP PET 2004]

A.             8
B.             0
C.             ? 2
D.             6
Answer» D.             6
1660.

If the vectors \[4i+11j+mk,\,7i+2j+6k\] and \[i+5j+4k\] are coplanar, then m is                            [Karnataka CET 2003]

A.             38
B.             0
C.             10
D.             ? 10
Answer» D.             ? 10
1661.

\[a\,.\,[(b+c)\times (a+b+c)]\] is equal to [IIT 1981; UPSEAT 2003; RPET 1988, 2002; MP PET 2004]

A.             [a b c]
B.             2[a b c]
C.             3[a b c]
D.             0
Answer» E.
1662.

If a and b be parallel vectors, then [a c b] =

A.             0
B.             1
C.             2
D.             None of these
Answer» B.             1
1663.

If u, v and w are three non-coplanar vectors, then \[(u+v-w)\,.\,[(u-v)\times (v-w)]\] equals [AIEEE 2003; DCE 2005]

A.             0
B.             \[u\,.\,(v\times w)\]
C.             \[u\,.\,(w\times v)\]
D.             \[3u\,.\,(v\times w)\]
Answer» C.             \[u\,.\,(w\times v)\]
1664.

The volume of the parallelopiped whose conterminous edges are \[i-j+k,\,\,2i-4j+5k\]and \[3i-5j+2k\] is [Kerala (Engg.) 2002]

A.             4
B.             3
C.             2
D.             8         
Answer» E.
1665.

a.(b × c) is equal to [RPET 2001]

A.             b.(a × c)
B.             c.(b × a)
C.                 It is obvious.
D.             None of these
Answer» D.             None of these
1666.

If \[a,\,b,\,c\] are vectors such that \[[a\,b\,c\,]=4\], then \[[a\times b\,\,b\times c\,\,c\times a]\] = [AIEEE 2002]

A.             16
B.             64
C.             4
D.             8
Answer» B.             64
1667.

\[(\mathbf{a}+\mathbf{b})\,.\,(\mathbf{b}+\mathbf{c})\times (\mathbf{a}+\mathbf{b}+\mathbf{c})=\]                                    [EAMCET 2002]

A.             ? [a b c]
B.             [a b c]
C.             0
D.             2[a b c]
Answer» C.             0
1668.

Let \[a=i-k,\,\,\,b=xi+j+(1-x)\,k\],\[c=yi+xj+(1+x-y)k\]. Then \[[a\,\,b\,\,c]\] depends on [IIT Screening 2001; AIEEE 2005]

A.             Only x
B.             Only y
C.             Neither x nor y
D.             Both x and y
Answer» D.             Both x and y
1669.

Let  \[\overrightarrow{A}=i+j+k\], \[\overrightarrow{B}=i,\,\overrightarrow{C}={{C}_{1}}i+{{C}_{2}}j+{{C}_{3}}k\]. If \[{{C}_{2}}=-1\], and \[{{C}_{3}}=1\], then to make three vectors coplanar         [AMU 2000]

A.             \[{{C}_{1}}=0\]
B.             \[{{C}_{1}}=1\]
C.             \[{{C}_{1}}=2\]
D.             No value of \[{{C}_{1}}\] can be found
Answer» E.
1670.

\[a=i+j+k,\,\mathbf{b}=2i-4k,\,c=i+\lambda \,j+3k\] are coplanar, then the value of \[\lambda \] is [MP PET 2000]

A.             5/2
B.             3/5
C.             7/3
D.             None of these
Answer» E.
1671.

If a, b, c are any three coplanar unit vectors, then

A.             \[\mathbf{a}\,.\,(\mathbf{b}\times \mathbf{c})=1\]
B.             \[\mathbf{a}\,.\,(\mathbf{b}\times \mathbf{c})=3\]
C.             \[(\mathbf{a}\times \mathbf{b})\,.\,\mathbf{c}=0\]
D.             \[(\mathbf{c}\times \mathbf{a})\,.\,\mathbf{b}=1\]
Answer» D.             \[(\mathbf{c}\times \mathbf{a})\,.\,\mathbf{b}=1\]
1672.

If the vectors \[i+3j-2k\], \[2i-j+4k\] and \[3i+2j+xk\] are coplanar, then the value of x is                 [Karnataka CET 2000]

A.             ? 2
B.             2
C.             1
D.             3
Answer» C.             1
1673.

If \[a,\,b\] and c are unit coplanar vectors then the scalar triple product \[[2a-b\,\,2b-c\,\,2c-a]\] is equal to    [IIT Screening 2000; Kerala (Engg.) 2005]

A.             0
B.             1
C.             \[-\sqrt{3}\]
D.             \[\sqrt{3}\]
Answer» B.             1
1674.

Given vectors a, b, c such that \[\mathbf{a}\,.(\mathbf{b}\times \mathbf{c})\]\[=\lambda \ne 0,\,\] the value of \[(\mathbf{b}\times \mathbf{c})\,.\,(\mathbf{a}+\mathbf{b}+\mathbf{c})/\lambda \]  is                            [AMU 1999]

A.             3         
B.             1
C.             \[-3\lambda \]
D.             \[3/\lambda \]
Answer» C.             \[-3\lambda \]
1675.

If vectors \[\vec{A}=2\mathbf{i}+3\mathbf{j}+4\mathbf{k}\], \[\vec{B}=\mathbf{i}+\mathbf{j}+5\mathbf{k}\], and \[\vec{C}\] form a left handed system, then \[\vec{C}\] is                      [Roorkee 1999]

A.             11i ? 6j ? k
B.             ? 11i + 6j + k
C.             11i ? 6j + k
D.             ? 11i + 6j ? k
Answer» C.             11i ? 6j + k
1676.

If \[\mathbf{a,}\,\mathbf{b,}\,\mathbf{c}\] are non-coplanar vectors and \[\mathbf{d}=\lambda \mathbf{a}+\mu \,\mathbf{b}+\nu \mathbf{c},\] then \[\lambda \] is equal to [Roorkee 1999]

A.             \[\frac{[\mathbf{d}\,\mathbf{b}\,\mathbf{c}]}{[\mathbf{b}\,\mathbf{a}\,\mathbf{c}]}\]
B.             \[\frac{[\mathbf{b}\,\mathbf{c}\,\mathbf{d}]}{[\mathbf{b}\,\mathbf{c}\,\mathbf{a}]}\]
C.             \[\frac{[\mathbf{b}\,\mathbf{d}\,\mathbf{c}]}{[\mathbf{a}\,\mathbf{b}\,\mathbf{c}]}\]
D.             \[\frac{[\mathbf{c}\,\mathbf{b}\,\mathbf{d}\,]}{[\mathbf{a}\,\mathbf{b}\,\mathbf{c}]}\]
Answer» C.             \[\frac{[\mathbf{b}\,\mathbf{d}\,\mathbf{c}]}{[\mathbf{a}\,\mathbf{b}\,\mathbf{c}]}\]
1677.

Which of the following expressions are meaningful [IIT 1998; RPET 2001]

A.             \[\mathbf{u}\,.\,(\mathbf{v}\times \mathbf{w})\]
B.             \[(\mathbf{u}\,.\,\mathbf{v})\,.\,\mathbf{w}\]
C.             \[(\mathbf{u}\,.\,\mathbf{v})\,\mathbf{w}\]
D.             \[\mathbf{u}\times (\mathbf{v}\,.\,\mathbf{w})\]
Answer» B.             \[(\mathbf{u}\,.\,\mathbf{v})\,.\,\mathbf{w}\]
1678.

For three vectors u, v, w which of the following expressions is not equal to any of the remaining three         [IIT 1998]

A.             \[\mathbf{u}\,.\,(\mathbf{v}\times \mathbf{w})\]
B.             \[\,(\mathbf{v}\times \mathbf{w})\,.\,\mathbf{u}\,\]
C.             \[\mathbf{v}\,.\,(\mathbf{u}\times \mathbf{w})\]
D.             \[(\mathbf{u}\times \mathbf{v})\,.\,\mathbf{w}\]
Answer» D.             \[(\mathbf{u}\times \mathbf{v})\,.\,\mathbf{w}\]
1679.

If three conterminous edges of a parallelopiped are represented by \[\mathbf{a}-\mathbf{b},\,\,\mathbf{b}-\mathbf{c}\] and \[\mathbf{c}-\mathbf{a}\], then its volume is                                       [MP PET 1999; Pb. CET 2003]

A.             [a b c]
B.             2 [a b c]
C.             \[\,{{[\mathbf{a}\,\,\mathbf{b}\,\,\mathbf{c}]}^{2}}\]
D.             0
Answer» E.
1680.

If the vectors \[2\mathbf{i}-3\mathbf{j},\,\,\mathbf{i}+\mathbf{j}-\mathbf{k}\] and \[3\mathbf{i}-\mathbf{k}\] form three concurrent edges of a parallelopiped, then the volume of the parallelopiped is        [IIT 1983; RPET 1995; DCE 2001; Kurukshetra CEE 1998; MP PET 2001]

A.             8
B.             10
C.             4
D.             14
Answer» D.             14
1681.

\[\mathbf{a}\,.\,(\mathbf{a}\times \mathbf{b})=\] [MP PET 1996]

A.             b . b
B.             \[{{a}^{2}}b\]
C.             0
D.             \[{{a}^{2}}+ab\]
Answer» D.             \[{{a}^{2}}+ab\]
1682.

If \[\mathbf{a}=-3\mathbf{i}+7\mathbf{j}+5\mathbf{k},\] \[\mathbf{b}=-3\mathbf{i}+7\mathbf{j}-3\mathbf{k}\], \[\mathbf{c}=7\mathbf{i}-5\mathbf{j}-3\mathbf{k}\] are the three coterminous edges of a parallelopiped, then its volume is [MP PET 1996]

A.             108
B.             210
C.             272
D.             308
Answer» D.             308
1683.

If \[\mathbf{a}=3\mathbf{i}-\mathbf{j}+2\mathbf{k},\] \[\mathbf{b}=2\mathbf{i}+\mathbf{j}-\mathbf{k},\] then \[\mathbf{a}\times (\mathbf{a}\,.\,\mathbf{b})=\] [Karnataka CET 1994]

A.             3a
B.             \[3\sqrt{14}\]
C.             0
D.             None of these
Answer» E.
1684.

Volume of the parallelopiped whose coterminous edges are \[2\mathbf{i}-3\mathbf{j}+4\mathbf{k},\,\,\mathbf{i}+2\mathbf{j}-2\mathbf{k},\,\,3\mathbf{i}-\mathbf{j}+\mathbf{k},\] is [EAMCET 1993]

A.             5 cubic unit
B.             6 cubic unit
C.             7 cubic unit
D.             8 cubic unit
Answer» D.             8 cubic unit
1685.

If the vectors \[2\mathbf{i}-3\mathbf{j}+4\mathbf{k},\,\,\mathbf{i}+2\mathbf{j}-\mathbf{k}\] and \[x\mathbf{i}-\mathbf{j}+2\mathbf{k}\] are coplanar, then \[x=\] [EAMCET 1994]

A.             \[\frac{8}{5}\]
B.             \[\frac{5}{8}\]
C.             0
D.             1
Answer» B.             \[\frac{5}{8}\]
1686.

If a,b,c are three coplanar vectors, then \[[\mathbf{a}+\mathbf{b}\,\,\mathbf{b}+\mathbf{c}\,\,\mathbf{c}+\mathbf{a}]=\] [MP PET 1995]

A.             [a b c]
B.             2 [a b c]
C.             3 [a b c]
D.             0
Answer» E.
1687.

If a, b, c be any three non-coplanar vectors, then \[[\mathbf{a}+\mathbf{b}\,\,\,\mathbf{b}+\mathbf{c}\,\,\,\mathbf{c}+\mathbf{a}]=\]     [RPET 1988; MP PET 1990, 02; Kerala (Engg.) 2002]

A.             \[|\mathbf{a}\,\mathbf{b}\,\mathbf{c}|\]
B.             2\[[\mathbf{a}\,\mathbf{b}\,\mathbf{c}]\]
C.             \[{{[\,\mathbf{a}\,\mathbf{b}\,\mathbf{c}\,]}^{2}}\]
D.             \[2\,{{[\,\mathbf{a}\,\mathbf{b}\,\mathbf{c}\,]}^{2}}\]
Answer» C.             \[{{[\,\mathbf{a}\,\mathbf{b}\,\mathbf{c}\,]}^{2}}\]
1688.

If the given vectors \[(-bc,\,{{b}^{2}}+bc,\,{{c}^{2}}+bc),\] \[({{a}^{2}}+ac,\,-ac,\,{{c}^{2}}+ac)\] and \[({{a}^{2}}+ab,\,{{b}^{2}}+ab,\,-ab)\] are coplanar, where none of a, b and c is zero, then

A.             \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}=1\]
B.             \[bc+ca+ab=0\]
C.             \[a+b+c=0\]
D.             \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}=bc+ca+ab\]
Answer» C.             \[a+b+c=0\]
1689.

Three concurrent edges OA, OB, OC of a parallelopiped are represented by three vectors \[2\mathbf{i}+\mathbf{j}-\mathbf{k},\,\,\mathbf{i}+2\mathbf{j}+3\mathbf{k}\] and \[-3\mathbf{i}-\mathbf{j}+\mathbf{k},\] the volume of the solid so formed in cubic unit is [Kurukshetra CEE 1998]

A.             5
B.             6
C.             7
D.             8
Answer» B.             6
1690.

If \[\mathbf{a}=2\mathbf{i}+\mathbf{j}-\mathbf{k},\,\,\mathbf{b}=\mathbf{i}+2\mathbf{j}+\mathbf{k}\] and \[\mathbf{c}=\mathbf{i}-\mathbf{j}+2\mathbf{k},\] then \[\mathbf{a}\,.\,(\mathbf{b}\times \mathbf{c})=\]                                    [RPET 1989, 2001]

A.             6
B.             10
C.             12
D.             24
Answer» D.             24
1691.

If three vectors \[\mathbf{a}=12\mathbf{i}+4\mathbf{j}+3\mathbf{k},\,\,\]\[\mathbf{b}=8\mathbf{i}-12\mathbf{j}-9\mathbf{k}\] and \[\mathbf{c}=33\mathbf{i}-4\mathbf{j}-24\mathbf{k}\] represents a cube, then its volume will be [Roorkee 1988]

A.             616
B.             308
C.             154
D.             None of these
Answer» E.
1692.

If \[\mathbf{i},\,\mathbf{j},\,\mathbf{k}\] are the unit vectors and mutually perpendicular, then \[[\mathbf{i}\,\mathbf{k}\,\mathbf{j}]\] is equal to                            [RPET 1986]

A.             0
B.             ? 1
C.             1
D.             None of these
Answer» C.             1
1693.

If a, b, c are any three vectors and their inverse are \[{{\mathbf{a}}^{-1}},\,{{\mathbf{b}}^{-1}},\,{{\mathbf{c}}^{-1}}\]and \[[\mathbf{a}\,\mathbf{b}\,\mathbf{c}]\ne 0,\] then \[[{{\mathbf{a}}^{-1}}\,{{\mathbf{b}}^{-1}}\,{{\mathbf{c}}^{-1}}]\] will be [Roorkee 1989]

A.             Zero
B.             One
C.             Non-zero
D.             [a b c]
Answer» D.             [a b c]
1694.

Let a, b, c be distinct non-negative numbers. If the vectors \[a\mathbf{i}+a\mathbf{j}+c\mathbf{k},\,\,\mathbf{i}+\mathbf{k}\] and \[c\mathbf{i}+c\mathbf{j}+b\mathbf{k}\] lie in a plane, then c is [IIT 1993; AIEEE 2005]

A.             The arithmetic mean of a and b
B.           The geometric mean of a and b
C.             The harmonic mean of a and b
D.             Equal to zero
Answer» C.             The harmonic mean of a and b
1695.

The volume of the parallelopiped whose edges are represented by \[-12\mathbf{i}+\alpha \mathbf{k},\,\,3\mathbf{j}-\mathbf{k}\] and \[2\mathbf{i}+\mathbf{j}-15\mathbf{k}\] is 546. Then \[\alpha =\]            [IIT Screening 1989; MNR 1987]

A.             3
B.             2
C.             ? 3
D.             ­? 2
Answer» D.             ­? 2
1696.

If a, b, c are three non-coplanar vector, then \[\frac{\mathbf{a}\,.\,\mathbf{b}\times \mathbf{c}}{\mathbf{c}\times \mathbf{a}\,.\,\mathbf{b}}+\frac{\mathbf{b}\,.\,\mathbf{a}\times \mathbf{c}}{\mathbf{c}\,.\,\mathbf{a}\times \mathbf{b}}\]=          [IIT 1985, 86; UPSEAT 2003]

A.             0
B.             2
C.             ? 2
D. None of these
Answer» B.             2
1697.

The function \[f(x)=x(x+3){{e}^{-(1/2)x}}\] satisfies all the conditions of  Rolle's theorem in [?3, 0]. The value of c is

A.            0
B.            ?1
C.            ? 2
D.            ? 3
Answer» D.            ? 3
1698.

If from mean value theorem, \[f'({{x}_{1}})=\frac{f(b)-f(a)}{b-a}\], then                                                                       [MP PET 1999]

A.            \[a<{{x}_{1}}\le b\]
B.            \[a\le {{x}_{1}}<b\]
C.            \[a<{{x}_{1}}<b\]
D.            \[a\le {{x}_{1}}\le b\]
Answer» D.            \[a\le {{x}_{1}}\le b\]
1699.

Rolle's theorem is true for the function \[f(x)={{x}^{2}}-4\]in the interval

A.            [?2, 0]
B.            [?2, 2]
C.            \[\left[ 0,\,\frac{1}{2} \right]\]
D.            \[[0,\,\,2]\]
Answer» C.            \[\left[ 0,\,\frac{1}{2} \right]\]
1700.

From mean value theorem \[f(b)-f(a)=\] \[(b-a)f'({{x}_{1}});\] \[a

A.            \[\sqrt{ab}\]
B.            \[\frac{a+b}{2}\]
C.            \[\frac{2ab}{a+b}\]
D.            \[\frac{b-a}{b+a}\]
Answer» B.            \[\frac{a+b}{2}\]