-
question_answer1)
\[(\mathbf{a}\,.\,\mathbf{i})\,\mathbf{i}+(\mathbf{a}\,.\,\mathbf{j})\mathbf{j}+(\mathbf{a}\,.\,\mathbf{k})\,\mathbf{k}=\] [Karnataka CET 2004]
A)
a done
clear
B)
2 a done
clear
C)
0 done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer2)
If \[\mathbf{r}\,.\,\mathbf{i}=\mathbf{r}\,.\,\mathbf{j}=\mathbf{r}\,.\,\mathbf{k}\] and \[|\mathbf{r}|\,\,=3,\] then \[\mathbf{r}=\]
A)
\[\pm \,3\,(\mathbf{i}+\mathbf{j}+\mathbf{k})\] done
clear
B)
\[\pm \,\frac{1}{3}\,(\mathbf{i}+\mathbf{j}+\mathbf{k})\] done
clear
C)
\[\pm \,\frac{1}{\sqrt{3}}\,(\mathbf{i}+\mathbf{j}+\mathbf{k})\] done
clear
D)
\[\pm \,\sqrt{3}\,(\mathbf{i}+\mathbf{j}+\mathbf{k})\] done
clear
View Solution play_arrow
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question_answer3)
If a, b, c are non-zero vectors such that \[\mathbf{a}\,\,.\,\,\mathbf{b}=\mathbf{a}\,\,.\,\,\mathbf{c},\] then which statement is true [RPET 2001]
A)
b = c done
clear
B)
\[\mathbf{a}\,\bot \,(\mathbf{b}-\mathbf{c})\] done
clear
C)
\[\mathbf{b}=\mathbf{c}\] or \[\mathbf{a}\,\bot \,(\mathbf{b}-\mathbf{c})\] done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer4)
If a and b be unlike vectors, then a . b =
A)
| a | | b | done
clear
B)
? | a | | b | done
clear
C)
0 done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer5)
If a, b, c are unit vectors such that \[\mathbf{a}+\mathbf{b}+\mathbf{c}=\mathbf{0},\] then \[\mathbf{a}\,\,.\,\,\mathbf{b}+\mathbf{b}\,\,.\,\,\mathbf{c}+\mathbf{c}\,\,.\,\,\mathbf{a}=\] [MP PET 1988; Karnataka CET 2000; UPSEAT 2003, 04]
A)
1 done
clear
B)
3 done
clear
C)
? 3/2 done
clear
D)
3/2 done
clear
View Solution play_arrow
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question_answer6)
If a, b, c are mutually perpendicular vectors of equal magnitudes, then the angle between the vectors a and \[\mathbf{a}+\mathbf{b}+\mathbf{c}\] is
A)
\[\frac{\pi }{3}\] done
clear
B)
\[\frac{\pi }{6}\] done
clear
C)
\[{{\cos }^{-1}}\frac{1}{\sqrt{3}}\] done
clear
D)
\[\frac{\pi }{2}\] done
clear
View Solution play_arrow
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question_answer7)
If a, b, c are mutually perpendicular unit vectors, then \[|\mathbf{a}+\mathbf{b}+\mathbf{c}|\,\,=\] [Karnataka CET 2002, 05; J & K 2005]
A)
\[\sqrt{3}\] done
clear
B)
3 done
clear
C)
1 done
clear
D)
0 done
clear
View Solution play_arrow
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question_answer8)
If \[|\mathbf{a}|+|\mathbf{b}|\,=\,|\mathbf{c}|\] and \[\mathbf{a}+\mathbf{b}=\mathbf{c},\] then the angle between a and b is
A)
\[\frac{\pi }{2}\] done
clear
B)
\[\pi \] done
clear
C)
0 done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer9)
If a has magnitude 5 and points north-east and vector b has magnitude 5 and points north-west, then \[|\,\,\mathbf{a}-\mathbf{b}\,\,|\,=\] [MNR 1984]
A)
25 done
clear
B)
5 done
clear
C)
\[7\sqrt{3}\] done
clear
D)
\[5\sqrt{2}\] done
clear
View Solution play_arrow
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question_answer10)
If q be the angle between the unit vectors a and b, then \[\cos \frac{\theta }{2}=\] [MP PET 1998; Pb. CET 2002]
A)
\[\frac{1}{2}\,|\mathbf{a}-\mathbf{b}|\] done
clear
B)
\[\frac{1}{2}\,|\mathbf{a}+\mathbf{b}|\] done
clear
C)
\[\frac{|\mathbf{a}-\mathbf{b}|}{|\mathbf{a}+\mathbf{b}|}\] done
clear
D)
\[\frac{|\mathbf{a}+\mathbf{b}|}{|\mathbf{a}-\mathbf{b}|}\] done
clear
View Solution play_arrow
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question_answer11)
If \[|\mathbf{a}|\,=3,\,\,|\mathbf{b}|\,=4,\,\,|\mathbf{c}|\,=\,\,5\] and \[\mathbf{a}+\mathbf{b}+\mathbf{c}=0,\] then the angle between a and b is [MP PET 1989; Bihar CEE 1994]
A)
0 done
clear
B)
\[\frac{\pi }{6}\] done
clear
C)
\[\frac{\pi }{3}\] done
clear
D)
\[\frac{\pi }{2}\] done
clear
View Solution play_arrow
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question_answer12)
If \[|\mathbf{a}+\mathbf{b}|\,\,>\,\,|\mathbf{a}-\mathbf{b}|,\] then the angle between a and b is
A)
Acute done
clear
B)
Obtuse done
clear
C)
\[\frac{\pi }{2}\] done
clear
D)
\[\pi \] done
clear
View Solution play_arrow
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question_answer13)
If a, b, c are three vectors such that \[\mathbf{a}=\mathbf{b}+\mathbf{c}\] and the angle between b and c is \[\pi /2,\] then [EAMCET 2003]
A)
\[{{a}^{2}}={{b}^{2}}+{{c}^{2}}\] done
clear
B)
\[{{b}^{2}}={{c}^{2}}+{{a}^{2}}\] done
clear
C)
\[{{c}^{2}}={{a}^{2}}+{{b}^{2}}\] done
clear
D)
\[2{{a}^{2}}-{{b}^{2}}={{c}^{2}}\] (Note : Here \[a=\,\,|\mathbf{a}|,\,\,b=\,|\,\mathbf{b}|,\,\,c=\,|\mathbf{c}|)\] done
clear
View Solution play_arrow
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question_answer14)
If the angle between the vectors a and b be q and \[\mathbf{a}\,.\,\mathbf{b}=\cos \theta ,\] then the true statement is
A)
a and b are equal vectors done
clear
B)
a and b are like vectors done
clear
C)
a and b are unlike vectors done
clear
D)
a and b are unit vectors done
clear
View Solution play_arrow
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question_answer15)
If the vector \[\mathbf{i}+\mathbf{j}+\mathbf{k}\] makes angles \[\alpha ,\,\beta ,\,\gamma \]with vectors \[\mathbf{i},\,\mathbf{j},\mathbf{k}\]respectively, then
A)
\[\alpha =\beta \ne \gamma \] done
clear
B)
\[\alpha =\gamma \ne \beta \] done
clear
C)
\[\beta =\gamma \ne \alpha \] done
clear
D)
\[\alpha =\beta =\gamma \] done
clear
View Solution play_arrow
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question_answer16)
\[{{(\mathbf{r}\,.\,\mathbf{i})}^{2}}+{{(\mathbf{r}\,.\,\mathbf{j})}^{2}}+{{(\mathbf{r}\,.\,\mathbf{k})}^{2}}=\]
A)
\[3{{r}^{2}}\] done
clear
B)
\[{{r}^{2}}\] done
clear
C)
0 done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer17)
The value of b such that scalar product of the vectors \[(\mathbf{i}+\mathbf{j}+\mathbf{k})\] with the unit vector parallel to the sum of the vectors \[(2\mathbf{i}+4\mathbf{j}-5\mathbf{k})\] and \[(b\mathbf{i}+2\mathbf{j}+3\mathbf{k})\] is 1, is [MNR 1992; Roorkee 1985, 95; Kurukshetra CEE 1998; UPSEAT 2000]
A)
? 2 done
clear
B)
? 1 done
clear
C)
0 done
clear
D)
1 done
clear
View Solution play_arrow
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question_answer18)
If a unit vector lies in yz?plane and makes angles of \[{{30}^{o}}\] and \[{{60}^{o}}\] with the positive y-axis and z-axis respectively, then its components along the co-ordinate axes will be
A)
\[\frac{\sqrt{3}}{2},\,\,\frac{1}{2},\,0\] done
clear
B)
\[0,\,\,\frac{\sqrt{3}}{2},\,\,\frac{1}{2}\] done
clear
C)
\[\frac{\sqrt{3}}{2},\,\,0,\,\,\frac{1}{2}\] done
clear
D)
\[0,\,\,\frac{1}{2},\,\frac{\sqrt{3}}{2}\] done
clear
View Solution play_arrow
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question_answer19)
If \[\overrightarrow{{{F}_{1}}}=\mathbf{i}-\mathbf{j}+\mathbf{k},\] \[\overrightarrow{{{F}_{2}}}=-\mathbf{i}+2\mathbf{j}-\mathbf{k},\] \[\overrightarrow{{{F}_{3}}}=\mathbf{j}-\mathbf{k},\] \[\vec{A}=4\mathbf{i}-3\mathbf{j}-2\mathbf{k}\] and \[\vec{B}=6\mathbf{i}+\mathbf{j}-3\mathbf{k},\] then the scalar product of \[\overrightarrow{{{F}_{1}}}+\overrightarrow{{{F}_{2}}}+\overrightarrow{{{F}_{3}}}\]and \[\overrightarrow{AB}\] will be [Roorkee 1980]
A)
3 done
clear
B)
6 done
clear
C)
9 done
clear
D)
12 done
clear
View Solution play_arrow
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question_answer20)
If the moduli of a and b are equal and angle between them is \[{{120}^{o}}\] and \[\mathbf{a}\,.\,\mathbf{b}=-\,8,\] then | a | is equal to [RPET 1986]
A)
? 5 done
clear
B)
? 4 done
clear
C)
4 done
clear
D)
5 done
clear
View Solution play_arrow
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question_answer21)
If \[|\mathbf{a}|\,\,=3,\,\,\,|\mathbf{b}\,\,|\,\,=4\] and the angle between a and b be \[{{120}^{o}}\], then \[|4\mathbf{a}+3\mathbf{b}|\,\,=\]
A)
25 done
clear
B)
12 done
clear
C)
13 done
clear
D)
7 done
clear
View Solution play_arrow
-
question_answer22)
A vector whose modulus is \[\sqrt{51}\] and makes the same angle with \[\mathbf{a}=\frac{\mathbf{i}-2\mathbf{j}+2\mathbf{k}}{3},\,\,\mathbf{b}=\frac{-\,4\mathbf{i}-3\mathbf{k}}{5}\] and \[\mathbf{c}=\mathbf{j},\] will be [Roorkee 1987]
A)
\[5\mathbf{i}+5\mathbf{j}+\mathbf{k}\] done
clear
B)
\[5\mathbf{i}+\mathbf{j}-5\mathbf{k}\] done
clear
C)
\[5\mathbf{i}+\mathbf{j}+5\mathbf{k}\] done
clear
D)
\[\pm \,(5\mathbf{i}-\mathbf{j}-5\mathbf{k})\] done
clear
View Solution play_arrow
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question_answer23)
If a, b, c are coplanar vectors, then [IIT 1989]
A)
\[\left| \,\begin{matrix} \mathbf{a} & \mathbf{b} & \mathbf{c} \\ \mathbf{b} & \mathbf{c} & \mathbf{a} \\ \mathbf{c} & \mathbf{a} & \mathbf{b} \\ \end{matrix}\, \right|=\mathbf{0}\] done
clear
B)
\[\left| \,\begin{matrix} \mathbf{a} & \mathbf{b} & \mathbf{c} \\ \mathbf{a}\,.\,\mathbf{a} & \mathbf{a}\,.\,\mathbf{b} & \mathbf{a}\,.\,\mathbf{c} \\ \mathbf{b}\,.\,\mathbf{a} & \mathbf{b}\,.\,\mathbf{b} & \mathbf{b}\,.\,\mathbf{c} \\ \end{matrix}\, \right|=\mathbf{0}\] done
clear
C)
\[\left| \,\begin{matrix} \mathbf{a} & \mathbf{b} & \mathbf{c} \\ \mathbf{c}\,.\,\mathbf{a} & \mathbf{c}\,.\,\mathbf{b} & \mathbf{c}\,.\,\mathbf{c} \\ \mathbf{b}\,.\,\mathbf{a} & \mathbf{b}\,.\,\mathbf{c} & \mathbf{b}\,.\,\mathbf{b} \\ \end{matrix}\, \right|=\mathbf{0}\] done
clear
D)
\[\left| \,\begin{matrix} \mathbf{a} & \mathbf{b} & \mathbf{c} \\ \mathbf{a}\,.\,\mathbf{b} & \mathbf{a}\,.\,\mathbf{a} & \mathbf{a}\,.\,\mathbf{c} \\ \mathbf{c}\,.\,\mathbf{a} & \mathbf{c}\,.\,\mathbf{c} & \mathbf{c}\,.\,\mathbf{b} \\ \end{matrix}\, \right|=\mathbf{0}\] done
clear
View Solution play_arrow
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question_answer24)
If \[\vec{\lambda }\] is a unit vector perpendicular to plane of vector a and b and angle between them is q, then a . b will be [RPET 1985]
A)
\[|\mathbf{a}|\,\,|\mathbf{b}|\,\sin \theta \,\vec{\lambda }\] done
clear
B)
\[|\mathbf{a}|\,\,|\mathbf{b}|\,\cos \,\,\theta \,\vec{\lambda }\] done
clear
C)
\[|\mathbf{a}|\,\,|\mathbf{b}|\,\cos \,\,\theta \,\] done
clear
D)
\[|\mathbf{a}|\,\,|\mathbf{b}|\,\sin \theta \,\] done
clear
View Solution play_arrow
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question_answer25)
If \[\mathbf{p}=\mathbf{i}-2\mathbf{j}+3\mathbf{k}\] and \[\mathbf{q}=3\mathbf{i}+\mathbf{j}+2\mathbf{k},\] then a vector along r which is linear combination of p and q and also perpendicular to q is [MNR 1986]
A)
\[\mathbf{i}+5\mathbf{j}-4\mathbf{k}\] done
clear
B)
\[\mathbf{i}-5\mathbf{j}+4\mathbf{k}\] done
clear
C)
\[-\frac{1}{2}\,(\mathbf{i}+5\mathbf{j}-4\mathbf{k})\] done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer26)
If \[\mathbf{d}=\lambda \,(\mathbf{a}\times \mathbf{b})+\mu \,(\mathbf{b}\times \mathbf{c})+\nu \,(\mathbf{c}\times \mathbf{a})\]and \[[\mathbf{a}\,\mathbf{b}\,\mathbf{c}]=\frac{1}{8},\] then \[\lambda +\mu +\nu \] is equal to
A)
\[8\mathbf{d}\,.\,(\mathbf{a}+\mathbf{b}+\mathbf{c})\] done
clear
B)
\[8\mathbf{d}\,\times \,(\mathbf{a}+\mathbf{b}+\mathbf{c})\] done
clear
C)
\[\frac{\mathbf{d}\,}{8}.\,(\mathbf{a}+\mathbf{b}+\mathbf{c})\] done
clear
D)
\[\frac{\mathbf{d}\,}{8}\times \,(\mathbf{a}+\mathbf{b}+\mathbf{c})\] done
clear
View Solution play_arrow
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question_answer27)
The horizontal force and the force inclined at an angle \[{{60}^{o}}\] with the vertical, whose resultant is in vertical direction of P kg, are [IIT 1983]
A)
\[P,2P\] done
clear
B)
\[P,\,\,P\sqrt{3}\] done
clear
C)
\[2P,\,\,P\sqrt{3}\] done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer28)
If a and b are mutually perpendicular vectors, then \[{{(\mathbf{a}+\mathbf{b})}^{2}}=\] [MP PET 1994; Pb. CET 2002]
A)
\[\mathbf{a}+\mathbf{b}\] done
clear
B)
\[\mathbf{a}-\mathbf{b}\] done
clear
C)
\[{{a}^{2}}-{{b}^{2}}\] done
clear
D)
\[{{(\mathbf{a}-\mathbf{b})}^{2}}\] done
clear
View Solution play_arrow
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question_answer29)
\[\mathbf{a}\,.\,\mathbf{b}=0,\] then [RPET 1995]
A)
\[\mathbf{a}\,\bot \,\mathbf{b}\] done
clear
B)
a || b done
clear
C)
Angle between a and b is \[{{60}^{o}}\] done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer30)
If \[|\mathbf{a}|\,\,=3,\,\,\,|\mathbf{b}|\,\,=1,\,\,|\mathbf{c}|\,\,=4\] and \[\mathbf{a}+\mathbf{b}+\mathbf{c}=\mathbf{0},\] then \[\mathbf{a}\,.\,\mathbf{b}+\mathbf{b}\,.\,\mathbf{c}+\mathbf{c}\,.\,\mathbf{a}=\] [MP PET 1995; RPET 2000]
A)
? 13 done
clear
B)
? 10 done
clear
C)
13 done
clear
D)
10 done
clear
View Solution play_arrow
-
question_answer31)
If ABCDEF is regular hexagon, the length of whose side is a, then \[\overrightarrow{AB}\,\,.\,\overrightarrow{AF}+\frac{1}{2}\,{{\overrightarrow{BC}}^{2}}=\]
A)
a done
clear
B)
\[{{a}^{2}}\] done
clear
C)
\[2\,{{a}^{2}}\] done
clear
D)
0 done
clear
View Solution play_arrow
-
question_answer32)
If in a right angled triangle ABC, the hypotenuse \[AB=p,\] then \[\overrightarrow{AB}\,\,.\,\,\overrightarrow{AC}+\overrightarrow{BC}\,.\,\,\overrightarrow{BA}+\overrightarrow{CA}\,\,.\,\,\overrightarrow{CB}\] is equal to
A)
\[2{{p}^{2}}\] done
clear
B)
\[\frac{{{p}^{2}}}{2}\] done
clear
C)
\[{{p}^{2}}\] done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer33)
A, B, C, D are any four points, then \[\overrightarrow{AB}\,\,.\,\,\overrightarrow{CD}\,\,+\,\overrightarrow{\,BC}\,\,.\,\,\overrightarrow{AD}\,\,+\overrightarrow{CA}\,\,.\,\,\overrightarrow{BD}\,\,=\] [MNR 1986]
A)
\[2\,\,\overrightarrow{AB}\,\,.\,\,\overrightarrow{BC}\,\,.\,\,\overrightarrow{CD}\] done
clear
B)
\[\overrightarrow{AB}\,\,+\,\,\overrightarrow{BC}\,\,+\,\,\overrightarrow{CD}\] done
clear
C)
\[5\sqrt{3}\] done
clear
D)
0 done
clear
View Solution play_arrow
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question_answer34)
The vector a coplanar with the vectors i and j, perpendicular to the vector \[\mathbf{b}=4\mathbf{i}-3\mathbf{j}+5\mathbf{k}\] such that \[|\mathbf{a}|\,=\,|\,\mathbf{b}|\] is
A)
\[\sqrt{2}\,(3\mathbf{i}+4\mathbf{j})\] or \[-\sqrt{2}\,(3\mathbf{i}+4\mathbf{j})\] done
clear
B)
\[\sqrt{2}\,(4\mathbf{i}+3\mathbf{j})\] or \[-\sqrt{2}\,(4\mathbf{i}+3\mathbf{j})\] done
clear
C)
\[\sqrt{3}\,(4\mathbf{i}+5\mathbf{j})\] or \[-\sqrt{3}\,(4\mathbf{i}+5\mathbf{j})\] done
clear
D)
\[\sqrt{3}\,(5\mathbf{i}+4\mathbf{j})\] or \[-\sqrt{3}\,(5\mathbf{i}+4\mathbf{j})\] done
clear
View Solution play_arrow
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question_answer35)
If a is any vector in space, then [MP PET 1997]
A)
\[\mathbf{a}=(\mathbf{a}\,.\,\mathbf{i})\,\mathbf{i}+\,(\mathbf{a}\,.\,\mathbf{j})\,\mathbf{j}+\,(\mathbf{a}\,.\,\mathbf{k})\,\mathbf{k}\] done
clear
B)
\[\mathbf{a}=(\mathbf{a}\,\times \,\mathbf{i})+\,(\mathbf{a}\,\times \,\mathbf{j})\,+\,(\mathbf{a}\,\times \,\mathbf{k})\,\] done
clear
C)
\[\mathbf{a}=\mathbf{j}\,(\mathbf{a}\,.\,\mathbf{i})\,+\mathbf{k}\,(\mathbf{a}\,.\,\mathbf{j})\,+\,\mathbf{i}\,(\mathbf{a}\,.\,\mathbf{k})\,\] done
clear
D)
\[\mathbf{a}=(\mathbf{a}\,\times \,\mathbf{i})\times \mathbf{i}+\,(\mathbf{a}\,\times \,\mathbf{j})\times \mathbf{j}\,+\,(\mathbf{a}\,\times \,\mathbf{k})\times \mathbf{k}\,\] done
clear
View Solution play_arrow
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question_answer36)
If vectors \[\mathbf{a},\,b,\,\mathbf{c}\] satisfy the condition \[|\mathbf{a}-\mathbf{c}|=|\mathbf{b}-\mathbf{c}|\], then \[(\mathbf{b}-\mathbf{a})\,.\,\left( \mathbf{c}-\frac{\mathbf{a}+\mathbf{b}}{\mathbf{2}} \right)\]is equal to [AMU 1999]
A)
0 done
clear
B)
?1 done
clear
C)
1 done
clear
D)
2 done
clear
View Solution play_arrow
-
question_answer37)
(a .b) c and (a.c) b are [RPET 2000]
A)
Two like vectors done
clear
B)
Two equal vectors done
clear
C)
Two vectors in direction of a done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer38)
If \[a=(1,\,-1,\,2),\ b=(-2,\,3,\,5)\], \[\mathbf{c}=(2\,,\,-2,\,4)\] and i is the unit vector in the x-direction, then \[(a-2b+3c)\,.\,i=\] [Karnataka CET 2001]
A)
11 done
clear
B)
15 done
clear
C)
18 done
clear
D)
36 done
clear
View Solution play_arrow
-
question_answer39)
For any three non-zero vectors \[{{r}_{1}},\,{{r}_{2}}\] and \[{{r}_{3}}\], \[\left| \,\begin{matrix} {{r}_{1}}\,.\,{{r}_{1}} & {{r}_{1}}\,.\,{{r}_{2}} & {{r}_{1}}\,.\,{{r}_{3}} \\ {{r}_{2}}\,.\,{{r}_{1}} & {{r}_{2}}\,.\,{{r}_{2}} & {{r}_{2}}\,.\,{{r}_{3}} \\ {{r}_{3}}\,.\,{{r}_{1}} & {{r}_{3}}\,.\,{{r}_{2}} & {{r}_{3}}\,.\,{{r}_{3}} \\ \end{matrix} \right|=0\]. Then which of the following is false [AMU 2000]
A)
All the three vectors are parallel to one and the same plane done
clear
B)
All the three vectors are linearly dependent done
clear
C)
This system of equation has a non-trivial solution done
clear
D)
All the three vectors are perpendicular to each other done
clear
View Solution play_arrow
-
question_answer40)
Let a, b and c be vectors with magnitudes 3, 4 and 5 respectively and a + b + c = 0, then the values of a.b + b.c + c.a is [IIT 1995; DCE 2001; AIEEE 2002; UPSEAT 2002; Kerala (Engg.) 2005]
A)
47 done
clear
B)
25 done
clear
C)
50 done
clear
D)
? 25 done
clear
View Solution play_arrow
-
question_answer41)
If a and b are adjacent sides of a rhombus, then [RPET 2001]
A)
a.b = 0 done
clear
B)
a × b = 0 done
clear
C)
a.a = b.b done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer42)
If x and y are two unit vectors and \[\pi \] is the angle between them, then \[\frac{1}{2}|x-y|\] is equal to [UPSEAT 2001]
A)
0 done
clear
B)
\[\pi /2\] done
clear
C)
1 done
clear
D)
\[\pi /4\] done
clear
View Solution play_arrow
-
question_answer43)
If \[a\,.\,i=a\,.\,(i+j)=a\,.\,(i+j+k)\], then a = [EAMCET 2002]
A)
i done
clear
B)
k done
clear
C)
j done
clear
D)
i + j + k done
clear
View Solution play_arrow
-
question_answer44)
If i, j, k are unit vectors, then [MP PET 2001]
A)
i . j \[=\]1 done
clear
B)
i . i \[=\]1 done
clear
C)
\[\mathbf{i}\times \mathbf{j}=1\] done
clear
D)
\[\mathbf{i}\times (\mathbf{j}\times \mathbf{k})=1\] done
clear
View Solution play_arrow
-
question_answer45)
If \[|a|\,=\,|\mathbf{b}|,\] then \[(a+b)\,.\,(a-b)\] is [MP PET 2002]
A)
Positive done
clear
B)
Negative done
clear
C)
Zero done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer46)
\[a,\,b,\,c\] are three vectors, such that \[a+b+c=0\], \[|a|\,=1,\,|b|\,=2,\,|c|\,=3\], then \[a.b+b.c+c.a\] is equal to [AIEEE 2003]
A)
0 done
clear
B)
? 7 done
clear
C)
7 done
clear
D)
1 done
clear
View Solution play_arrow
-
question_answer47)
A unit vector which is coplanar to vector \[\mathbf{i}+\mathbf{j}+2k\] and \[\mathbf{i}+2\mathbf{j}+\mathbf{k}\] and perpendicular to \[\mathbf{i}+\mathbf{j}+\mathbf{k},\] is [IIT 1992; Kurukshetra CEE 2002]
A)
\[\frac{\mathbf{i}-\mathbf{j}}{\sqrt{2}}\] done
clear
B)
\[\pm \,\left( \frac{\mathbf{j}-\mathbf{k}}{\sqrt{2}} \right)\] done
clear
C)
\[\frac{\mathbf{k}-\mathbf{i}}{\sqrt{2}}\] done
clear
D)
\[\frac{\mathbf{i}+\mathbf{j}+\mathbf{k}}{\sqrt{3}}\] done
clear
View Solution play_arrow
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question_answer48)
If \[|\mathbf{a}|\,=3,\,\,|\mathbf{b}|\,=4\] then a value of l for which \[\mathbf{a}+\lambda \mathbf{b}\] is perpendicular to \[\mathbf{a}-\lambda \mathbf{b}\] is [Karnataka CET 2004]
A)
\[\mathbf{a}=2\,\mathbf{i}+2\,\mathbf{j}+3\,\mathbf{k},\,\,\mathbf{b}=-\mathbf{i}+2\,\mathbf{j}+\mathbf{k}\] done
clear
B)
\[\frac{3}{4}\] done
clear
C)
\[\frac{3}{2}\] done
clear
D)
\[\frac{4}{3}\] done
clear
View Solution play_arrow
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question_answer49)
\[\mathbf{a},\,\mathbf{b}\] and c are three vectors with magnitude \[|\mathbf{a}|\,=4,\] \[|\mathbf{b}|\,=4,\] \[|\mathbf{c}|\,=2\] and such that \[\mathbf{a}\] is perpendicular to \[(\mathbf{b}+\mathbf{c}),\,\mathbf{b}\] is perpendicular to \[(\mathbf{c}+\mathbf{a})\] and \[\mathbf{c}\] is perpendicular to \[(\mathbf{a}+\mathbf{b}).\] It follows that \[|\mathbf{a}+\mathbf{b}+\mathbf{c}|\] is equal to [UPSEAT 2004]
A)
9 done
clear
B)
6 done
clear
C)
5 done
clear
D)
4 done
clear
View Solution play_arrow
-
question_answer50)
The angle between the vectors \[3\,\mathbf{i}+\mathbf{j}+2\,\mathbf{k}\] and \[2\,\mathbf{i}-2\,\mathbf{j}+4\,\mathbf{k}\] is [MP PET 1990]
A)
\[{{\cos }^{-1}}\frac{2}{\sqrt{7}}\] done
clear
B)
\[{{\sin }^{-1}}\frac{2}{\sqrt{7}}\] done
clear
C)
\[{{\cos }^{-1}}\frac{2}{\sqrt{5}}\] done
clear
D)
\[{{\sin }^{-1}}\frac{2}{\sqrt{5}}\] done
clear
View Solution play_arrow
-
question_answer51)
If the position vectors of the points A, B, C, D be \[\mathbf{i}+\mathbf{j}+\mathbf{k},\,\,2\,\mathbf{i}+5\,\mathbf{j},\,\,3\,\mathbf{i}+2\,\mathbf{j}-3\mathbf{k}\]and \[\mathbf{i}-6\,\mathbf{j}-\mathbf{k},\] then the angle between the vectors \[\overrightarrow{AB}\] and \[\overrightarrow{CD}\] is
A)
\[\frac{\pi }{4}\] done
clear
B)
\[\frac{\pi }{3}\] done
clear
C)
\[\frac{\pi }{2}\] done
clear
D)
\[\pi \] done
clear
View Solution play_arrow
-
question_answer52)
If q be the angle between the unit vectors a and b, then \[\mathbf{a}-\sqrt{2}\,\mathbf{b}\] will be a unit vector if \[\theta =\]
A)
\[\frac{\pi }{6}\] done
clear
B)
\[\frac{\pi }{4}\] done
clear
C)
\[p\mathbf{i}+q\mathbf{j}+r\mathbf{k}\] done
clear
D)
\[\frac{2\pi }{3}\] done
clear
View Solution play_arrow
-
question_answer53)
If the angle between a and b be \[{{30}^{o}}\], then the angle between 3 a and ? 4 b will be
A)
\[{{150}^{o}}\] done
clear
B)
\[{{90}^{o}}\] done
clear
C)
\[{{120}^{o}}\] done
clear
D)
\[{{30}^{o}}\] done
clear
View Solution play_arrow
-
question_answer54)
The angle between the vectors \[\mathbf{i}-\mathbf{j}+\mathbf{k}\] and \[\mathbf{i}+2\mathbf{j}+\mathbf{k}\] is [BIT Ranchi 1991]
A)
\[{{\cos }^{-1}}\left( \frac{1}{\sqrt{15}} \right)\] done
clear
B)
\[{{\cos }^{-1}}\left( \frac{4}{\sqrt{15}} \right)\] done
clear
C)
\[{{\cos }^{-1}}\left( \frac{4}{15} \right)\] done
clear
D)
\[\frac{\pi }{2}\] done
clear
View Solution play_arrow
-
question_answer55)
The position vector of vertices of a triangle ABC are \[4\mathbf{i}-2\mathbf{j},\,\mathbf{i}+4\mathbf{j}-3\mathbf{k}\] and \[-\mathbf{i}+5\mathbf{j}+\mathbf{k}\] respectively, then \[\angle ABC=\] [RPET 1988, 97]
A)
\[\pi /6\] done
clear
B)
\[\pi /4\] done
clear
C)
\[\pi /3\] done
clear
D)
\[\pi /2\] done
clear
View Solution play_arrow
-
question_answer56)
The value of x for which the angle between the vectors \[\mathbf{a}=x\mathbf{i}-3\mathbf{j}-\mathbf{k},\,\,\mathbf{b}=2x\mathbf{i}+x\mathbf{j}-\mathbf{k}\] is acute and the angle between the vectors b and the axis of ordinate is obtuse, are
A)
1, 2 done
clear
B)
? 2, ? 3 done
clear
C)
x > 0 done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer57)
If a and b are unit vectors and \[\mathbf{a}-\mathbf{b}\] is also a unit vector, then the angle between a and b is [RPET 1991; MP PET 1995; Pb. CET 2001]
A)
\[\frac{\pi }{4}\] done
clear
B)
\[\frac{\pi }{3}\] done
clear
C)
\[\frac{\pi }{2}\] done
clear
D)
\[\frac{2\pi }{3}\] done
clear
View Solution play_arrow
-
question_answer58)
If q be the angle between two vectors a and b, then \[\mathbf{a}.\mathbf{b}\] \[\ge 0\] if [MP PET 1995]
A)
\[0\le \theta \le \pi \] done
clear
B)
\[\frac{\pi }{2}\le \theta \le \pi \] done
clear
C)
\[0\le \theta \le \frac{\pi }{2}\] done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer59)
If \[\mathbf{a}=\mathbf{i}+2\mathbf{j}-3\mathbf{k}\] and \[\mathbf{b}=3\mathbf{i}-\mathbf{j}+2\mathbf{k},\] then the angle between the vectors \[\mathbf{a}+\mathbf{b}\] and \[\mathbf{a}-\mathbf{b}\] is [Karnataka CET 1994; Orissa JEE 2005]
A)
\[{{30}^{o}}\] done
clear
B)
\[{{60}^{o}}\] done
clear
C)
\[{{90}^{o}}\] done
clear
D)
View Solution play_arrow
-
question_answer60)
The value of x for which the angle between the vectors \[\mathbf{a}=-\,3\mathbf{i}+x\mathbf{j}+\mathbf{k}\] and \[\mathbf{b}=x\mathbf{i}+2x\mathbf{j}+\mathbf{k}\] is acute and the angle between b and x-axis lies between \[\pi /2\] and \[\pi \]satisfy [Kurukshetra CEE 1996]
A)
\[x>0\] done
clear
B)
\[x<0\] done
clear
C)
\[x>1\] only done
clear
D)
\[x<-1\] only done
clear
View Solution play_arrow
-
question_answer61)
The angle between the vectors \[(2\mathbf{i}+6\mathbf{j}+3\mathbf{k})\] and \[(12\mathbf{i}-4\mathbf{j}+3\mathbf{k})\] is [MP PET 1996]
A)
\[{{\cos }^{-1}}\left( \frac{1}{10} \right)\] done
clear
B)
\[{{\cos }^{-1}}\left( \frac{9}{11} \right)\] done
clear
C)
\[{{\cos }^{-1}}\left( \frac{9}{91} \right)\] done
clear
D)
\[{{\cos }^{-1}}\left( \frac{1}{9} \right)\] done
clear
View Solution play_arrow
-
question_answer62)
If the angle between two vectors \[\mathbf{i}+\mathbf{k}\] and \[\mathbf{i}-\mathbf{j}+a\mathbf{k}\] is \[\pi /3,\] then the value of \[a=\] [MP PET 1997]
A)
2 done
clear
B)
4 done
clear
C)
? 2 done
clear
D)
0 done
clear
View Solution play_arrow
-
question_answer63)
If three vectors a, b, c satisfy \[\mathbf{a}+\mathbf{b}+\mathbf{c}=\mathbf{0}\] and \[|\mathbf{a}|\,\,=\,\,3,\,\] \[|\mathbf{b}|\,=5,\] \[|\mathbf{c}|\,\,=7,\] then the angle between a and b is [Kurukshetra CEE 1998; UPSEAT 2001; AIEEE 2002; MP PET 2002]
A)
\[{{30}^{o}}\] done
clear
B)
\[{{45}^{o}}\] done
clear
C)
\[{{60}^{o}}\] done
clear
D)
\[{{90}^{\text{o}}}\] done
clear
View Solution play_arrow
-
question_answer64)
If a, b and c are unit vectors such that \[\mathbf{a}+\mathbf{b}-\mathbf{c}=0,\] then the angle between a and b is [Roorkee Qualifying 1998; MP PET 1999; UPSEAT 2000; RPET 2002]
A)
\[\pi /6\] done
clear
B)
\[\pi /3\] done
clear
C)
\[\pi /2\] done
clear
D)
\[2\pi /3\] done
clear
View Solution play_arrow
-
question_answer65)
If the sum of two unit vectors is a unit vector, then the magnitude of their difference is [Kurukshetra CEE 1996; RPET 1996]
A)
\[\sqrt{2}\] done
clear
B)
\[\sqrt{3}\] done
clear
C)
\[\frac{1}{\sqrt{3}}\] done
clear
D)
1 done
clear
View Solution play_arrow
-
question_answer66)
The angle between the vector \[2i+3j+k\] and \[2i-j-k\] is [MNR 1990; UPSEAT 2000]
A)
\[\pi /2\] done
clear
B)
\[\pi /4\] done
clear
C)
\[\pi /3\] done
clear
D)
0 done
clear
View Solution play_arrow
-
question_answer67)
If \[\theta \] be the angle between the vectors \[12+m-2=0\] and \[\mathbf{b}=6\mathbf{i}-3\mathbf{j}+2\mathbf{k}\], then [MP PET 2001, 03]
A)
\[\cos \theta =\frac{4}{21}\] done
clear
B)
\[\cos \theta =\frac{3}{19}\] done
clear
C)
\[\cos \theta =\frac{2}{19}\] done
clear
D)
\[\cos \theta =\frac{5}{21}\] done
clear
View Solution play_arrow
-
question_answer68)
If a and b are two unit vectors such that \[\mathbf{a}+2\,\mathbf{b}\] and \[5a-4b\] are perpendicular to each other, then the angle between a and b is [IIT Screening 2002]
A)
\[{{45}^{o}}\] done
clear
B)
\[{{60}^{o}}\] done
clear
C)
\[{{\cos }^{-1}}\left( \frac{1}{3} \right)\] done
clear
D)
\[{{\cos }^{-1}}\left( \frac{2}{7} \right)\] done
clear
View Solution play_arrow
-
question_answer69)
Let a and b be two unit vectors inclined at an angle \[\theta \], then \[\sin \,(\theta /2)\] is equal to [BIT Ranchi 1991; Karnataka CET 2000, 01; UPSEAT 2002]
A)
\[\frac{1}{2}|a-b|\] done
clear
B)
\[\frac{1}{2}|a+b|\] done
clear
C)
\[|a-b|\] done
clear
D)
\[|a+b|\] done
clear
View Solution play_arrow
-
question_answer70)
The angle between the vectors a + b and a ? b, when \[\mathbf{a}=(1,\,1,\,4)\] and \[b=(1,\,-1,\,4)\] is [Karnataka CET 2003]
A)
\[{{90}^{o}}\] done
clear
B)
\[{{45}^{o}}\] done
clear
C)
\[{{30}^{o}}\] done
clear
D)
\[{{15}^{o}}\] done
clear
View Solution play_arrow
-
question_answer71)
A vector of length 3 perpendicular to each of the vectors \[3\,\mathbf{i}+\mathbf{j}-4\,\mathbf{k}\] and \[6\,\mathbf{i}+5\,\mathbf{j}-2\,\mathbf{k}\] is
A)
\[2\,\mathbf{i}-2\,\mathbf{j}+\mathbf{k}\] done
clear
B)
\[-\,2\,\mathbf{i}+2\,\mathbf{j}+\mathbf{k}\] done
clear
C)
\[2\,\mathbf{i}+2\,\mathbf{j}-\mathbf{k}\] done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer72)
If \[\mathbf{a}\ne \mathbf{0},\,\,\mathbf{b}\ne \mathbf{0}\] and \[|\mathbf{a}+\mathbf{b}|\,=\,|\mathbf{a}-\mathbf{b}|,\] then the vectors a and b are [Roorkee 1986; MNR 1988; IIT Screening 1989; MP PET 1990, 97; RPET 1984, 90, 96, 99; KCET 1999]
A)
Parallel to each other done
clear
B)
Perpendicular to each other done
clear
C)
Inclined at an angle of \[{{60}^{o}}\] done
clear
D)
Neither perpendicular nor parallel done
clear
View Solution play_arrow
-
question_answer73)
The vector \[2\,\mathbf{i}+a\,\mathbf{j}+\mathbf{k}\] is perpendicular to the vector \[2\,\mathbf{i}-\mathbf{j}-k,\] if \[a=\] [MP PET 1987]
A)
5 done
clear
B)
? 5 done
clear
C)
? 3 done
clear
D)
3 done
clear
View Solution play_arrow
-
question_answer74)
If \[\mathbf{a}=2\,\mathbf{i}+2\,\mathbf{j}+3\,\mathbf{k},\,\,\mathbf{b}=-\mathbf{i}+2\,\mathbf{j}+\mathbf{k}\] and \[c=3\,\mathbf{i}+\mathbf{j},\] then \[\mathbf{a}+t\,\mathbf{b}\] is perpendicular to c if \[t=\] [MNR 1979; MP PET 2002]
A)
2 done
clear
B)
4 done
clear
C)
6 done
clear
D)
8 done
clear
View Solution play_arrow
-
question_answer75)
The vector \[2\,\mathbf{i}+\mathbf{j}-\mathbf{k}\] is perpendicular to \[\mathbf{i}-4\mathbf{j}+\lambda \mathbf{k},\] if \[\lambda =\] [MNR 1983; MP PET 1988]
A)
0 done
clear
B)
? 1 done
clear
C)
? 2 done
clear
D)
? 3 done
clear
View Solution play_arrow
-
question_answer76)
The vectors \[2\,\mathbf{i}+3\,\mathbf{j}-4\,\mathbf{k}\] and \[a\,\mathbf{i}+b\,\mathbf{j}+c\,\mathbf{k}\] are perpendicular, when [MNR 1982; MP PET 1988; MP PET 2002]
A)
\[a=2,\,\,b=3,\,\,c=-4\] done
clear
B)
\[a=4,\,\,b=4,\,\,c=5\] done
clear
C)
\[a=4,\,\,b=4,\,\,c=-\,5\] done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer77)
A unit vector in the \[xy-\]plane which is perpendicular to \[4\mathbf{i}-3\mathbf{j}+\mathbf{k}\] is [RPET 1991]
A)
\[\frac{\mathbf{i}+\mathbf{j}}{\sqrt{2}}\] done
clear
B)
\[\frac{1}{5}(3\mathbf{i}+4\mathbf{j})\] done
clear
C)
\[\frac{1}{5}\,(3\mathbf{i}-4\mathbf{j})\] done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer78)
If \[l\,\mathbf{a}+m\,\mathbf{b}+n\,\mathbf{c}=\mathbf{0},\] where \[l,\,m,\,\,n\] are scalars and a, b, c are mutually perpendicular vectors, then
A)
\[l=m=n=1\] done
clear
B)
\[l+m+n=1\] done
clear
C)
\[l=m=n=0\] done
clear
D)
\[l\ne 0,\,\,m\ne 0,\,\,n\ne 0\] done
clear
View Solution play_arrow
-
question_answer79)
The unit normal vector to the line joining \[\mathbf{i}-\mathbf{j}\] and \[2\,\mathbf{i}+3\,\mathbf{j}\] and pointing towards the origin is [MP PET 1989]
A)
\[\frac{4\,\mathbf{i}-\mathbf{j}}{\sqrt{17}}\] done
clear
B)
\[\frac{-4\,\mathbf{i}+\mathbf{j}}{\sqrt{17}}\] done
clear
C)
\[\frac{2\,\mathbf{i}-3\,\mathbf{j}}{\sqrt{13}}\] done
clear
D)
\[\frac{-\,2\,\mathbf{i}+3\,\mathbf{j}}{\sqrt{13}}\] done
clear
View Solution play_arrow
-
question_answer80)
If the vectors \[a\,\mathbf{i}-2\mathbf{j}+3\mathbf{k}\] and \[3\mathbf{i}+6\mathbf{j}-5\mathbf{k}\] are perpendicular to each other, then a is given by [MP PET 1993]
A)
9 done
clear
B)
16 done
clear
C)
25 done
clear
D)
36 done
clear
View Solution play_arrow
-
question_answer81)
The value of \[\lambda \] for which the vectors \[2\lambda \mathbf{i}+\mathbf{j}-\mathbf{k}\] and \[2\mathbf{j}+\mathbf{k}\] are perpendicular, is [MP PET 1992]
A)
None done
clear
B)
? 1 done
clear
C)
1 done
clear
D)
Any value done
clear
View Solution play_arrow
-
question_answer82)
If the vectors \[a\mathbf{i}+b\mathbf{j}+c\mathbf{k}\] and \[p\mathbf{i}+q\mathbf{j}+r\mathbf{k}\] are perpendicular, then [RPET 1989]
A)
\[(a+b+c)\,(p+q+r)=0\] done
clear
B)
\[(a+b+c)\,(p+q+r)=1\] done
clear
C)
\[ap+bq+cr=0\] done
clear
D)
\[ap+bq+cr=1\] done
clear
View Solution play_arrow
-
question_answer83)
If \[\mathbf{a}=2\mathbf{i}+4\mathbf{j}+2\mathbf{k}\] and \[\mathbf{b}=8\mathbf{i}-3\mathbf{j}+\lambda \mathbf{k}\] and \[\mathbf{a}\,\bot \,\mathbf{b},\] then value of \[\lambda \] will be [RPET 1995]
A)
2 done
clear
B)
? 1 done
clear
C)
? 2 done
clear
D)
1 done
clear
View Solution play_arrow
-
question_answer84)
The vector \[\frac{1}{3}\,(2\mathbf{i}-2\mathbf{j}+\mathbf{k})\] is [IIT Screening 1994]
A)
A unit vector done
clear
B)
Makes an angle \[\frac{\pi }{3}\] with the vector \[2i-4\mathbf{j}+3\mathbf{k}\] done
clear
C)
Parallel to the vector \[-\mathbf{i}+\mathbf{j}-\frac{1}{2}\mathbf{k}\] done
clear
D)
Perpendicular to the vector \[3\mathbf{i}+2\mathbf{j}-2\mathbf{k}\] done
clear
View Solution play_arrow
-
question_answer85)
If the vectors \[a\mathbf{i}+2\mathbf{j}+3\mathbf{k}\] and \[-\mathbf{i}+5\mathbf{j}+a\mathbf{k}\] are perpendicular to each other, then \[a=\] [MP PET 1996]
A)
6 done
clear
B)
? 6 done
clear
C)
5 done
clear
D)
? 5 done
clear
View Solution play_arrow
-
question_answer86)
Which of the following is a true statement [Kurukshetra CEE 1996]
A)
\[(\mathbf{a}\times \mathbf{b})\times \mathbf{c}\] is coplanar with c done
clear
B)
\[(\mathbf{a}\times \mathbf{b})\times \mathbf{c}\] is perpendicular to a done
clear
C)
\[(\mathbf{a}\times \mathbf{b})\times \mathbf{c}\] is perpendicular to b done
clear
D)
\[(\mathbf{a}\times \mathbf{b})\times \mathbf{c}\] is perpendicular to c done
clear
View Solution play_arrow
-
question_answer87)
If \[\mathbf{a}=\mathbf{i}-2\mathbf{j}\] and \[\mathbf{b}=2\mathbf{i}+\lambda \mathbf{j}\] are parallel, then \[\lambda \] is [RPET 1996]
A)
4 done
clear
B)
2 done
clear
C)
? 2 done
clear
D)
? 4 done
clear
View Solution play_arrow
-
question_answer88)
If \[ai+6j-k\] and \[7i-3j+17k\] are perpendicular vectors, then the value of a is [Karnataka CET 2001]
A)
5 done
clear
B)
? 5 done
clear
C)
7 done
clear
D)
\[\frac{1}{7}\] done
clear
View Solution play_arrow
-
question_answer89)
If \[4i+j-k\] and \[3i+mj+2k\] are at right angle, then \[m=\] [Karnataka CET 2002]
A)
? 6 done
clear
B)
? 8 done
clear
C)
? 10 done
clear
D)
? 12 done
clear
View Solution play_arrow
-
question_answer90)
If the vectors \[3i+\lambda \,j+k\] and \[2i-j+8k\] are perpendicular, then \[\lambda \] is [Kerala (Engg.) 2002]
A)
? 14 done
clear
B)
7 done
clear
C)
14 done
clear
D)
1/7 done
clear
View Solution play_arrow
-
question_answer91)
If a and b are two non-zero vectors, then the component of b along a is [MP PET 1991]
A)
\[\frac{(\mathbf{a}\,.\,\mathbf{b})\,\mathbf{a}}{\mathbf{b}\,.\,\mathbf{b}}\] done
clear
B)
\[\frac{(\mathbf{a}\,.\,\mathbf{b})\,\mathbf{b}}{\mathbf{a}\,.\,\mathbf{a}}\] done
clear
C)
\[\frac{(\mathbf{a}\,.\,\mathbf{b})\,\mathbf{b}}{\mathbf{a}\,.\,\mathbf{b}}\] done
clear
D)
\[\frac{(\mathbf{a}\,.\,\mathbf{b})\,\mathbf{a}}{\mathbf{a}\,.\,\mathbf{a}}\] done
clear
View Solution play_arrow
-
question_answer92)
A vector of magnitude 14 lies in the xy-plane and makes an angle of \[{{60}^{o}}\] with x-axis. The components of the vector in the direction of x-axis and y-axis are
A)
\[7,\,\,7\sqrt{3}\] done
clear
B)
\[7\sqrt{3},\,\,7\] done
clear
C)
\[14\sqrt{3},\,\,14/\sqrt{3}\] done
clear
D)
\[14/\sqrt{3},\,\,14\sqrt{3}\] done
clear
View Solution play_arrow
-
question_answer93)
If \[\mathbf{a}=4\mathbf{i}+6\mathbf{j}\] and \[\mathbf{b}=3\,\mathbf{j}+4\,\mathbf{k},\] then the component of a along b is [IIT Screening 1989; MNR 1983, 87; UPSEAT 2000]
A)
\[\frac{18}{10\sqrt{3}}(3\mathbf{j}+4\mathbf{k})\] done
clear
B)
\[\frac{18}{25}(3\mathbf{j}+4\mathbf{k})\] done
clear
C)
\[\frac{18}{\sqrt{3}}(3\mathbf{j}+4\mathbf{k})\] done
clear
D)
\[(3\mathbf{j}+4\mathbf{k})\] done
clear
View Solution play_arrow
-
question_answer94)
Let \[\mathbf{b}=3\mathbf{j}+4\mathbf{k},\,\,\mathbf{a}=\mathbf{i}+\mathbf{j}\] and let \[{{\mathbf{b}}_{1}}\] and \[{{\mathbf{b}}_{2}}\] be component vectors of b parallel and perpendicular to a. If \[{{\mathbf{b}}_{1}}=\frac{3}{2}\mathbf{i}+\frac{3}{2}\mathbf{j}\], then \[{{\mathbf{b}}_{2}}=\] [MP PET 1989]
A)
\[\frac{3}{2}\mathbf{i}+\frac{3}{2}\mathbf{j}+4\mathbf{k}\] done
clear
B)
\[-\frac{3}{2}\mathbf{i}+\frac{3}{2}\mathbf{j}+4\mathbf{k}\] done
clear
C)
\[-\frac{3}{2}\mathbf{i}+\frac{3}{2}\mathbf{j}\] done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer95)
The component of \[\mathbf{i}+\mathbf{j}\] along \[\mathbf{j}+\mathbf{k}\] will be
A)
\[\frac{\mathbf{i}+\mathbf{j}}{2}\] done
clear
B)
\[\frac{\mathbf{j}+\mathbf{k}}{2}\] done
clear
C)
\[\frac{\mathbf{k}+\mathbf{i}}{2}\] done
clear
D)
None of these done
clear
View Solution play_arrow
-
question_answer96)
The projection of vector \[2\mathbf{i}+3\mathbf{j}-2\mathbf{k}\] on the vector \[\mathbf{i}+2\mathbf{j}+3\mathbf{k}\] will be [RPET 1984, 90, 97, 99; Karnataka CET 2004]
A)
\[\frac{1}{\sqrt{14}}\] done
clear
B)
\[\frac{2}{\sqrt{14}}\] done
clear
C)
\[\frac{3}{\sqrt{14}}\] done
clear
D)
\[\sqrt{14}\] done
clear
View Solution play_arrow
-
question_answer97)
If vector \[\mathbf{a}=2\mathbf{i}-3\mathbf{j}+6\mathbf{k}\] and vector \[\mathbf{b}=-2\mathbf{i}+2\mathbf{j}-\mathbf{k},\] then \[\frac{\text{Projection of vector }\mathbf{a}\text{ on vector }\mathbf{b}}{\text{Projection of vector }\mathbf{b}\text{ on vector }\mathbf{a}}=\] [MP PET 1994, 99; Pb. CET 2000]
A)
\[\frac{3}{7}\] done
clear
B)
\[\frac{7}{3}\] done
clear
C)
3 done
clear
D)
7 done
clear
View Solution play_arrow
-
question_answer98)
The projection of a along b is [RPET 1995]
A)
\[\frac{\mathbf{a}\,.\,\mathbf{b}}{|\mathbf{a}|}\] done
clear
B)
\[\frac{\mathbf{a}\,\times \,\mathbf{b}}{|\mathbf{a}|}\] done
clear
C)
\[\frac{\mathbf{a}\,.\,\mathbf{b}}{|\mathbf{b}|}\] done
clear
D)
\[\frac{\mathbf{a}\,\times \,\mathbf{b}}{|\mathbf{b}|}\] done
clear
View Solution play_arrow
-
question_answer99)
If \[a=2i+j+2k\] and \[b=5i-3j+k,\] then the projection of b on a is [Karnataka CET 2002]
A)
3 done
clear
B)
4 done
clear
C)
5 done
clear
D)
6 done
clear
View Solution play_arrow
-
question_answer100)
The projection of the vector \[i-2j+k\] on the vector \[4i-4j+7k\] is [RPET 1990; MNR 1980; MP PET 2002; UPSEAT 2002; Pb. CET 2004]
A)
\[\frac{5\sqrt{6}}{10}\] done
clear
B)
\[\frac{19}{9}\] done
clear
C)
\[\frac{9}{19}\] done
clear
D)
\[\frac{\sqrt{6}}{19}\] done
clear
View Solution play_arrow