CBSE Questions for Class 12 Commerce Maths Vector Algebra Quiz 2 - MCQExams.com

Give the vector from $$(2,-7,0)$$ to $$(1,-3,-5)$$.
  • $$(3,4,-5)$$
  • $$(-1,4,-5)$$
  • $$(3,-10,-5)$$
  • None of these
Find the vector which joins the point A$$(4,5,6)$$ to B$$(10,11,12)$$.
  • $$14\hat i+16\hat j+18\hat k$$
  • $$-6\hat i-6\hat j-6\hat k$$
  • $$6\hat i+6\hat j+6\hat k$$
  • None of these
Give the vector from $$(1,-3,-5)$$ to $$(2,-7,0)$$.
  • $$(1,-4,5)$$
  • $$(3,-10,-5)$$
  • $$(1,4,5)$$
  • None of these
Find the vector $$w$$ with the initial point $$(4,1,2)$$ and final point $$(1,6,5)$$.
  • $$(3,-5,-3)$$
  • $$(0,7,3)$$
  • $$(-3,5,3)$$
  • None of these
Find $$2v$$, when $$u=(3,4,-2)$$ and $$v=(0,-4,0)$$.
  • $$(0,-8,0)$$
  • $$(3,8,0)$$
  • $$(3,-8,-2)$$
  • None of these
Find the magnitude of the vector which joins the point $$A$$$$(4,5,6)$$ to $$B$$$$(10,11,12)$$.
  • $$12.29$$
  • $$10.39$$
  • $$10.29$$
  • None of these
Which of the following is not a unit vector for all values of $$\theta$$?
  • $$(\cos\theta)i - (\sin\theta)j$$
  • $$(\sin\theta)i + (\cos\theta)j$$
  • $$(\sin2\theta)i - (\cos\theta)j$$
  • $$(\cos2\theta)i - (\sin2\theta)j$$
Find the vector $$w$$ with the initial point $$(8,-10,3)$$ and final point $$(1,10,7)$$.
  • $$(7,10,-4)$$
  • $$(-4,10,4)$$
  • $$(-7,20,4)$$
  • None of these
The vector joining vector $$\vec{A}$$ to $$\vec{B}$$  is represented by:
  • $$\vec{A}-\vec{B}$$
  • $$\vec{B}-\vec{A}$$
  • $$\vec{A}+\vec{B}$$
  • None of these
Find the magnitude of the vector which joins the point $$A$$$$(-1,-3,-1)$$ to $$B$$$$(0,0,0)$$.
  • $$\sqrt{21}$$
  • $$\sqrt{10}$$
  • $$\sqrt{11}$$
  • None of these
Find the vector $$w$$ with the initial point $$(a,b,c)$$ and final point $$(a+1,b+2,c+3)$$.
  • $$(a,b+2,c+3)$$
  • $$(a-1,b-2,c-3)$$
  • $$(1,2,3)$$
  • None of these
Find the magnitude of the vector which joins the point $$A$$$$(a,2,c)$$ to $$B$$$$(a+1,5,c+3)$$.
  • $$\sqrt{18}$$
  • $$\sqrt{21}$$
  • $$\sqrt{20}$$
  • None of these
The coordinates of a point in $$3$$-D space is $$(3,1,2)$$. Then the position vector of the point is:
  • $$3\hat i + 3\hat j + 3\hat k$$
  • $$3\hat i + 2\hat j + \hat k$$
  • $$3\hat i + \hat j + 2\hat k$$
  • $$\hat i + 2\hat j + 3\hat k$$
If $$\vec{a} = (2, 1, -1), \vec{b} = (1,-1,0), \vec{c} = (5, -1, 1) $$ , then what is the unit vector parallel to $$ \vec{a} + \vec{b} - \vec{c} $$ in the opposite direction ?
  • $$\dfrac{\hat{i}+\hat{j}-2 \hat{k}}{3}$$
  • $$\dfrac{\hat{i}-2 \hat{j} + 2 \hat{k}}{3}$$
  • $$\dfrac{2 \hat{i} - \hat{j} + 2 \hat{k}}{3}$$
  • None of the above.
The position vectors of the points $$A$$ and $$B$$ are respectively $$3\hat { i } -5\hat { j } +2\hat { k } $$ and $$\hat { i } +\hat { j } -\hat { k } $$. What is the length of $$AB$$?
  • $$11$$
  • $$9$$
  • $$7$$
  • $$6$$
The unit vector perpendicular to the vector $$\hat{i}-\hat{j}$$ and $$\hat{i}+\hat{j}$$ forming a right handed system, is 
  • $$\hat{k}$$
  • $$-\hat{k}$$
  • $$\dfrac{\hat{i}-\hat{j}}{\sqrt{2}}$$
  • $$\dfrac{\hat{i}+\hat{j}}{\sqrt{2}}$$
Point $$(4, 0)$$ lies on ________.
  • $$\vec {XO}$$
  • $$\vec {YO}$$
  • $$\vec {OX}$$
  • $$\vec {OY}$$
State the following statement is True or False
If the starting and end points of a vector are collinear, it is known as a unit vector.
  • True
  • False
If the points $$A$$ and $$B$$ are $$\left( 1,2,-1 \right)$$ and $$ \left( 2,1,-1 \right)$$ respectively, then $$ \vec { AB } $$ is
  • $$\hat { i } +\hat { j } $$
  • $$\hat { i } -\hat { j } $$
  • $$2\hat { i } +\hat { j } -\hat { k } $$
  • $$\hat { i } +\hat { j } +\hat { k } $$
If $$\vec {a} . \hat {i} = \vec {a} . (\hat {i} + \hat {j}) = \vec {a} (\hat {i} + \hat {j} + \hat {k})$$, thus $$\vec {a}=$$
  • $$\hat {i}$$
  • $$\hat {i} + j$$
  • $$\hat {k} - \hat {j}$$
  • $$\hat {i} + \hat {j} + \hat {k}$$
The Polygon Law of Vector Addition is simply an extension of ____________. 
  • Parallelogram Law of Vector Addition
  • Triangular Law of Vector Addition
  • Both A and B
  • None of the above
If $$\left| {\widehat a - \widehat b} \right| = \sqrt 3 $$ , then  $$\left| {\widehat a + \widehat b} \right|$$  may be:-
  • $$1$$
  • $${{\sqrt 3 } \over 2}$$
  • Either (1) and (2)
  • None of these
If $$\left| \overrightarrow { a }  \right| =7,\ \left| \overrightarrow { b }  \right| =11,\ \left| \overrightarrow { a } +\overrightarrow { b }  \right| = 10\sqrt 3$$, then $$\left| \overrightarrow { a } -\overrightarrow { b }  \right| =$$
  • 10
  • $$\sqrt 10$$
  • $$2\sqrt 10$$
  • 20
For $$A(1, -2, 4), B(5, -1, 7), C(3, 6, -2), D(4, 5, -1)$$, the projection of $$\overline {AB}$$ on $$\overline {CD}$$ is ________.
  • $$(2\sqrt {3}, -2\sqrt {3}, 2\sqrt {3})$$
  • $$\dfrac {3}{13} (4, 1, 3)$$
  • $$(1, -1, 1)$$
  • $$(2, -2, 2)$$
In Polygon Law of Vector Addition, the head of first vector is joined to the tail of last vector.
  • True
  • False
If $$\bar{a}$$ is unit vector, then $$|\bar{a}\times \hat{i}|^2+|\bar{a}\times \hat{j}|^2+|\bar{a}\times \hat{k}|^2=$$ _____________.
  • $$2$$
  • $$1$$
  • $$0$$
  • $$3$$
If $$\vec { a } $$ and $$\vec { b } $$ are non-zero non-collinear vectors, then $$\left[ \vec { a } \quad \vec { b } \quad \hat { i }  \right] \hat { i } +\left[ \vec { a } \quad \vec { b } \quad \hat { j }  \right] \hat { j } +\left[ \vec { a } \quad \vec { b } \quad \hat { k }  \right] \hat { k } $$ is equal to
  • $$\vec { a } +\vec { b } $$
  • $$\vec { a } \times \vec { b } $$
  • $$\vec { a } -\vec { b } $$
  • $$\vec { b } \times \vec { a } $$
The vector $$z = 3 - 4i$$ is turned anticlockwise through an angle of $$180^{\circ}$$ and stretched $$\dfrac{5}{2}$$ times. The complex number corresponding to the newly obtained vector is ....
  • $$-\dfrac{15}{2}-10i$$
  • $$-\dfrac{15}{2}+10i$$
  • $$\dfrac{15}{2}+10i$$
  • $$\dfrac{15}{2}-10i$$
The set of values of $$c$$ for which the angle between the vectors $$cx\hat{i}-6\hat{j}+3\hat{k}$$ and $$x\hat{i}-2\hat{j}+2cx\hat{k}$$ is acute for every $$x\in R$$ is
  • $$(0,4/3)$$
  • $$[0,2/3]$$
  • $$(11/9,4/3)$$
  • $$[0,1/3)$$
The vector
$$\vec a + \vec b,\vec a - k\vec b$$ where $$k$$ scalar are collinear, for
  • $$k=0$$
  • $$k=-1$$
  • $$k=1$$
  • $$k=2$$
A line passes through the points whose position vectors $$ \hat { i } +\hat { j } -2\hat { k }$$ and $$\hat { i } -3\hat { j } +\hat { k }$$. Then the position vector of a point on it at a unit distance from the first point is 
  • $$\dfrac { 1 }{ 5 } \left( 5\hat { i } +\hat { j } -7\hat { k } \right)$$
  • $$\dfrac { 1 }{ 5 } \left( 5\hat { i } +9\hat { j } -13\hat { k } \right)$$
  • $$\left( \hat { i } -4\hat { j } +3\hat { k } \right)$$
  • $$\left( \hat { i } +4\hat { j } +3\hat { k } \right)$$
The position vector of point F, is?
  •  $$\dfrac{{3\left| {\overline a } \right|\,\left| {\overline c } \right|}}{{3\left| {\overline c } \right| + 2\left| {\overline a } \right|}}\,\,\,\left( {\dfrac{{\overrightarrow a }}{{\left| {\overline a } \right|}} + \dfrac{{\overrightarrow c }}{{\left| {\overline c } \right|}}} \right)$$
  • $$\vec{a}+\left|\dfrac{\vec{a}}{\vec{c}}\right|\vec{c}$$
  • $$\vec{a}+\dfrac{2|\vec{a}|}{|\vec{c}|}\vec{c}$$
  • $$\vec{a}-\left|\dfrac{\vec{a}}{\vec{c}}\right|\vec{c}$$
If $$\bar{a}=2\bar{i}+\bar{j}+\bar{k}, \bar{b}=\bar{i}+5\bar{j}, \bar{c}=4\bar{i}+4\bar{j}-2\bar{k}$$ then the length of the projection of $$(3\bar{a}-2\bar{b})$$ in the direction of $$\bar{c}$$.
  • $$3$$
  • $$-3$$
  • $$33$$
  • $$-33$$
In a triangle ABC, if $$ 2\vec { AC } =3\vec { CB }$$, then $$2\vec { OA } +3\vec { OB }$$ equals ?
  • $$5\vec { OC }$$
  • $$-\vec { OC }$$
  • $$\vec { OC }$$
  • None of these
If $$|\overrightarrow{a}| = 5, |\overrightarrow{a} - \overrightarrow{b}|=8$$ and $$|\overrightarrow{a} + \overrightarrow{b}| = 10$$, then $$|\overrightarrow{b}|$$ is equal to:
  • $$1$$
  • $$\sqrt{57}$$
  • $$3$$
  • $$57$$
If the vector $$OP$$ in $$XY$$ plane whose magnitude is $$\sqrt3$$ makes an angle $$60^o$$ with $$Y-$$ axis, the length of the component of the vector in direction of $$X-$$ axis is :
  • $$1$$
  • $$\sqrt3$$
  • $$\dfrac {1}{2}$$
  • $$\dfrac {3}{2}$$
If $$ | \overline{a} | = 1 , | \overline{b} | = 2, | \overline{a} - \overline{b} |^2 + | \overline{a} + 2 \overline{b} |^2 = 20, $$ then $$ ( \overline{a} , \overline{b} ) = $$ 
  • $$ \dfrac {\pi}{3} $$
  • $$ \dfrac {\pi}{4} $$
  • $$ \dfrac {\pi}{6} $$
  • $$ \dfrac {2 \pi}{3} $$
Which of the following expressions are meaningful?
  • $$\overrightarrow{u}.\left(\overrightarrow{v}\times \overrightarrow{w}\right) $$
  • $$\left(\overrightarrow{u}.\overrightarrow{v}\right).\overrightarrow{w}$$
  • $$\left(\overrightarrow{u}.\overrightarrow{v}\right)\overrightarrow{w} $$
  • $$\overrightarrow{u}\times \left(\overrightarrow{v}.\overrightarrow{w}\right)$$
For three vectors $$\overrightarrow{u},\overrightarrow{v},\overrightarrow{w}$$ which of the following expressions is not equal to any of remaining is
  • $$\overrightarrow{u}.\left(\overrightarrow{v}\times \overrightarrow{w}\right)$$
  • $$\left(\overrightarrow{v}\times \overrightarrow{w}\right).\overrightarrow{u} $$
  • $$\overrightarrow{v}.\left(\overrightarrow{u}\times \overrightarrow{w}\right)$$
  • $$\left(\overrightarrow{u}\times \overrightarrow{v}\right).\overrightarrow{w}$$
The ratio in which the line joining $$(2,-4,3)$$ and $$(-4,5,-6)$$ is divided by the plane $$3x+2y+z-4=0$$ is 
  • $$2 : 1$$
  • $$4 : 3$$
  • $$1 : 4$$
  • $$ 2 : 3$$
State true or false.
The vectors $$\vec { a } = - 4 \hat { i } - \hat { j } , \vec { b } = \hat { i } - 4 \hat { j } \text { and } \vec { c } = 3 \hat { i } + 5 \hat { j }$$ form a right angled-triangle.
  • True
  • False
A vector $$\overrightarrow { A } $$ points vertically downward(south)and $$\overrightarrow { B } $$ points towards east, then the vector product $$\overrightarrow { A } \times \overrightarrow { B } $$ is:
  • Along west
  • Along east
  • Zero
  • Outwards or inwards
$$\bar{a}$$ and $$\bar{b}$$ are the position vectors of A and B respectively. Points P and Q divide AB, internally and externally in the same ratio 2:1 , then PQ is equal to 
  • $$\frac{3}{2}(\bar{b}-\bar{a})$$
  • $$\frac{4}{3}(\bar{a}-\bar{b})$$
  • $$\frac{5}{6}(\bar{b}-\bar{a})$$
  • $$\frac{4}{3}(\bar{b}-\bar{a})$$
Two vector $$A$$ and $$B$$ have equal magnitudes. Then the vector $$A+B$$ is perpendicular to 
  • $$A\times{B}$$
  • $$A-B$$
  • $$3A-3B$$
  • All of these
The work done by the force $$\vec { F } = 2 \hat { i } - \hat { j } - \hat { \mathbf { k } }$$ in moung an object along the vector $$3 \hat { i } + 2 j - 5 \hat { k }$$ is
  • $$- 9$$ units
  • $$9$$ units
  • $$-15$$ units
  • None of these
Let $$\vec{a}=\hat{i}+\hat{j}+\hat{k}$$ and $$\vec{b}$$ is a vector such that $$\vec{a}.\vec{b}=0$$ and $$\vec{a}\times \vec{b}=0$$. Then which of following is correct?
  • $$\vec{b}=0$$
  • $$\vec{b} \perp\vec{a}$$
  • $$\vec{b}$$ is non-zero vector
  • $$\vec{b}$$ is parallel to $$\vec{a}$$
Given that $$\vec{ A } \times \vec{ B } =\vec{ B } \times \vec { C } =\vec { 0 } $$ if $$\vec{ A } \vec { B } \vec { C } $$ are not null vectors, Find the value of $$\vec{ A } \times \vec{ C } $$
  • $$\vec { A } \times \vec { B } $$
  • $$\vec { 0 } $$
  • $$\vec{ C } \times \vec { B } $$
  • $$\vec { C } \times \vec { A } $$
$$\vec{r}  = \vec{x}\hat{i}+\vec{y}\hat{j}$$ is the equation of:
  • $$yoz$$ plane
  • a straight line joining the points $$\vec{i}$$ and $$\vec{j}$$
  • $$zox$$ plane
  • $$xoy$$ plane
The unit vector in the direction of $$\overrightarrow{a}$$ is 
  • $$\dfrac{\vec{a}}{|\vec{a}|}$$
  • $$\vec{a}|\vec{a}|$$
  • $$a^2$$
  • $$\hat{i}$$
If $$\vec{a}$$ be the position vector whose tip is (5,-3), find the coordinates of a point B such that $$ \vec{AB} = \vec{a},$$ the coordinates of A being (4,-1).
  • (9, -4)
  • (-9, -4)
  • (9, 4)
  • none of these
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