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M.C.Q (1 Marks)

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15 questions · self-marked practice — reveal the answer and mark yourself.

Question 11 Mark
The value of $\hat{\text{i}}.\big(\hat{\text{j}}\times\hat{\text{k}}\big)+\hat{\text{j}}.\big(\hat{\text{i}}\times\hat{\text{k}}\big)+\hat{\text{k}}.\big(\hat{\text{i}}\times\hat{\text{j}}\big),$ is:
  1. 0
  2. -1
  3. 1
  4. 3
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Question 21 Mark
The unit vector perpendicular to the plane passing through points $\text{P}\big(\hat{\text{i}}-\hat{\text{j}}+2\hat{\text{k}}\big),\text{Q}\big(2\hat{\text{i}}-\hat{\text{k}}\big)$ and $\text{R}\big(2\hat{\text{j}}+\hat{\text{k}}\big)$ is:
  1. $2\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}$
  2. $\sqrt{6}\big(2\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}\big)$
  3. $\frac{1}{\sqrt{6}}\big(2\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}\big)$
  4. $\frac{1}{6}\big(2\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}\big)$
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Question 31 Mark
If $\theta$ is the angle between the vectors $2\hat{\text{i}}-2\hat{\text{j}}+4\hat{\text{k}}$ and $3\hat{\text{i}}+\hat{\text{j}}+2\hat{\text{k}},$ then $\sin\theta=$
  1. $\frac{2}{3}$
  2. $\frac{2}{\sqrt{7}}$
  3. $\frac{\sqrt{2}}{7}$
  4. $\sqrt{\frac{2}{7}}$
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Question 41 Mark
A unit vector perpendicular to both $\hat{\text{i}}+\hat{\text{j}}$ and $\hat{\text{j}}+\hat{\text{k}}$ is:
  1. $\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}}$
  2. $\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}$
  3. $\frac{1}{\sqrt{3}}\big(\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}\big)$
  4. $\frac{1}{\sqrt{3}}\big(\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}}\big)$
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Question 51 Mark
vectors $\vec{\text{a}}$ and $\vec{\text{b}}$ are inclined at angle $\theta=120^\circ.$ if $|\vec{\text{a}}|=1,\big|\vec{\text{b}}\big|=2,$ then $\big[\big(\vec{\text{a}}+3\vec{\text{b}}\big)\times\big(3\vec{\text{a}}-\vec{\text{b}}\big)\big]^2$ is equal to:
  1. 300
  2. 325
  3. 275
  4. 225
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Question 61 Mark
If $\big|\vec{\text{a}}\times\vec{\text{b}}\big|=4,\big|\vec{\text{a}}.\vec{\text{b}}\big|=2,$ then $|\vec{\text{a}}|^2\big|\vec{\text{b}}\big|^2=$
  1. 6
  2. 2
  3. 20
  4. 8
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Question 71 Mark
If $\vec{\text{a}}$ is any vector, then $\big(\vec{\text{a}}\times\hat{\text{i}}\big)^2+\big(\vec{\text{a}}\times\hat{\text{j}}\big)^2+\big(\vec{\text{a}}\times\hat{\text{k}}\big)^2=$
  1. $\vec{\text{a}}^2$
  2. $2\vec{\text{a}}^2$
  3. $3\vec{\text{a}}^2$
  4. $4\vec{\text{a}}^2$
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Question 81 Mark
If $\theta$ is the angle between any two vectors $\vec{\text{a}}$ and $\vec{\text{b}},$ then $\big|\vec{\text{a}}.\vec{\text{b}}\big|=\big|\vec{\text{a}}\times\vec{\text{b}}\big|$ when $\theta$ is equal to:
  1. $0$
  2. $\frac{\pi}{4}$
  3. $\frac{\pi}{2}$
  4. $\pi$
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Question 91 Mark
If $\vec{\text{a}}=\hat{\text{i}}+\hat{\text{j}}-\hat{\text{k}},\vec{\text{b}}=-\hat{\text{i}}+2\hat{\text{j}}+2\hat{\text{k}}$ and $\vec{\text{c}}=-\hat{\text{i}}+2\hat{\text{j}}-\hat{\text{k}},$ then a unit vector normal to the vectors $\vec{\text{a}}+\vec{\text{b}}$ and $\vec{\text{b}}-\vec{\text{c}}$ is:
  1. $\hat{\text{i}}$
  2. $\hat{\text{j}}$
  3. $\hat{\text{k}}$
  4. $\text{None of these}$
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Question 101 Mark
The vector $\vec{\text{b}}=3\hat{\text{i}}+4\hat{\text{k}}$ is to be written as the sum of a vector $\vec{\alpha}$ parallel to $\vec{\text{a}}=\hat{\text{i}}+\hat{\text{j}}$ and a vector $\vec{\beta}$ perpendicular to $\vec{\text{a}}.$ Then $\vec{\alpha}=$
  1. $\frac{3}{2}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
  2. $\frac{2}{3}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
  3. $\frac{1}{2}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
  4. $\frac{1}{3}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
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Question 111 Mark
If $\vec{\text{a}}=2\hat{\text{i}}-3\hat{\text{j}}-\hat{\text{k}}$ and $\vec{\text{b}}=\hat{\text{i}}+4\hat{\text{j}}-2\hat{\text{k}},$ then $\vec{\text{a}}\times\vec{\text{b}}$ is:
  1. $10\hat{\text{i}}+2\hat{\text{j}}+11\hat{\text{k}}$
  2. $10\hat{\text{i}}+3\hat{\text{j}}+11\hat{\text{k}}$
  3. $10\hat{\text{i}}-3\hat{\text{j}}+11\hat{\text{k}}$
  4. $10\hat{\text{i}}-2\hat{\text{j}}-10\hat{\text{k}}$
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Question 121 Mark
If $\vec{\text{a}}.\vec{\text{b}}=\vec{\text{a}}.\vec{\text{c}}$ and $\vec{\text{a}}\times\vec{\text{b}}=\vec{\text{a}}\times\vec{\text{c}}.\vec{\text{a}}\neq0,$ then:
  1. $\vec{\text{b}}=\vec{\text{c}}$
  2. $\vec{\text{b}}=\vec{0}$
  3. $\vec{\text{b}}+\vec{\text{c}}=\vec{0}$
  4. $\text{None of these}$
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Question 131 Mark
The value of $\big(\vec{\text{a}}\times\vec{\text{b}}\big)^2$ is:
  1. $|\vec{\text{a}}|^2+\big|\vec{\text{b}}\big|^2-\big(\vec{\text{a}}.\vec{\text{b}}\big)^2$
  2. $|\vec{\text{a}}|^2\big|\vec{\text{b}}\big|^2-\big(\vec{\text{a}}.\vec{\text{b}}\big)^2$
  3. $|\vec{\text{a}}|^2+\big|\vec{\text{b}}\big|^2-2\big(\vec{\text{a}}.\vec{\text{b}}\big)$
  4. $|\vec{\text{a}}|^2+\big|\vec{\text{b}}\big|^2-\vec{\text{a}}.\vec{\text{b}}$
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Question 141 Mark
If $\vec{\text{a}},\vec{\text{b}}$ represent the diagonals of a rhombus, then:
  1. $\vec{\text{a}}\times\vec{\text{b}}=\vec{0}$
  2. $\vec{\text{a}}.\vec{\text{b}}=0$
  3. $\vec{\text{a}}.\vec{\text{b}}=1$
  4. $\vec{\text{a}}\times\vec{\text{b}}=\vec{\text{a}}$
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Question 151 Mark
If $\hat{\text{i}},\hat{\text{j}},\hat{\text{k}}$ are unit vectors, then
  1. $\hat{\text{i}}.\hat{\text{j}}=1$
  2. $\hat{\text{i}}.\hat{\text{i}}=1$
  3. $\hat{\text{i}}\times\hat{\text{j}}=1$
  4. $\hat{\text{i}}\times\big(\hat{\text{j}}\times\hat{\text{k}}\big)=1$
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