Questions

M.C.Q (1 Marks)

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14 questions · auto-graded multiple-choice test.

MCQ 11 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 $\sin\theta=$
  • A
    $\frac{2}{3}$
  • B
    $\frac{2}{\sqrt{7}}$
  • $\frac{\sqrt{2}}{7}$
  • D
    $\sqrt{\frac{2}{7}}$
Answer
Correct option: C.
$\frac{\sqrt{2}}{7}$
$\frac{\sqrt{2}}{7}$
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MCQ 21 Mark
A unit vector perpendicular to both $\hat{\text{i}}+\hat{\text{j}}$ and $\hat{\text{j}}+\hat{\text{k}}$ is:
  • A
    $\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}}$
  • B
    $\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}$
  • C
    $\frac{1}{\sqrt{3}}\big(\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}\big)$
  • $\frac{1}{\sqrt{3}}\big(\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}}\big)$
Answer
Correct option: D.
$\frac{1}{\sqrt{3}}\big(\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}}\big)$
$\frac{1}{\sqrt{3}}\big(\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}}\big)$
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MCQ 31 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:
  • $300$
  • B
    $325$
  • C
    $275$
  • D
    $225$
Answer
Correct option: A.
$300$
$300$
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MCQ 41 Mark
If $\big|\vec{\text{a}}\times\vec{\text{b}}\big|=4,\big|\vec{\text{a}}.\vec{\text{b}}\big|=2,$ then $|\vec{\text{a}}|^2\big|\vec{\text{b}}\big|^2=$
  • A
    $6$
  • B
    $2$
  • $20$
  • D
    $8$
Answer
Correct option: C.
$20$
$20$
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MCQ 51 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:
  • A
    $0$
  • B
    $-1$
  • $1$
  • D
    $3$
Answer
Correct option: C.
$1$
$1$
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MCQ 61 Mark
If $\vec{\text{a}}$ is any vector, then $\big(\vec{\text{a}}\times\hat{\text{i}}\big)^2+\big(\vec{\text{a}}\times\hat{\text{j}}\big)^2+\big(\vec{\text{a}}\times\hat{\text{k}}\big)^2=$
  • A
    $\vec{\text{a}}^2$
  • $2\vec{\text{a}}^2$
  • C
    $3\vec{\text{a}}^2$
  • D
    $4\vec{\text{a}}^2$
Answer
Correct option: B.
$2\vec{\text{a}}^2$
$2\vec{\text{a}}^2$
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MCQ 71 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:
  • A
    $0$
  • $\frac{\pi}{4}$
  • C
    $\frac{\pi}{2}$
  • D
    $\pi$
Answer
Correct option: B.
$\frac{\pi}{4}$
$\frac{\pi}{4}$
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MCQ 81 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:
  • $\hat{\text{i}}$
  • B
    $\hat{\text{j}}$
  • C
    $\hat{\text{k}}$
  • D
    $\text{None of these}$
Answer
Correct option: A.
$\hat{\text{i}}$
$\hat{\text{i}}$
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MCQ 91 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 $\vec{\alpha}=$
  • A
    $\frac{3}{2}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
  • $\frac{2}{3}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
  • C
    $\frac{1}{2}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
  • D
    $\frac{1}{3}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
Answer
Correct option: B.
$\frac{2}{3}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
$\frac{2}{3}\big(\hat{\text{i}}+\hat{\text{j}}\big)$
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MCQ 101 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:
  • A
    $10\hat{\text{i}}+2\hat{\text{j}}+11\hat{\text{k}}$
  • $10\hat{\text{i}}+3\hat{\text{j}}+11\hat{\text{k}}$
  • C
    $10\hat{\text{i}}-3\hat{\text{j}}+11\hat{\text{k}}$
  • D
    $10\hat{\text{i}}-2\hat{\text{j}}-10\hat{\text{k}}$
Answer
Correct option: B.
$10\hat{\text{i}}+3\hat{\text{j}}+11\hat{\text{k}}$
$10\hat{\text{i}}+3\hat{\text{j}}+11\hat{\text{k}}$
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MCQ 111 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:
  • $\vec{\text{b}}=\vec{\text{c}}$
  • B
    $\vec{\text{b}}=\vec{0}$
  • C
    $\vec{\text{b}}+\vec{\text{c}}=\vec{0}$
  • D
    $\text{None of these}$
Answer
Correct option: A.
$\vec{\text{b}}=\vec{\text{c}}$
$\vec{\text{b}}=\vec{\text{c}}$
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MCQ 121 Mark
The value of $\big(\vec{\text{a}}\times\vec{\text{b}}\big)^2$ is:
  • A
    $|\vec{\text{a}}|^2+\big|\vec{\text{b}}\big|^2-\big(\vec{\text{a}}.\vec{\text{b}}\big)^2$
  • $|\vec{\text{a}}|^2\big|\vec{\text{b}}\big|^2-\big(\vec{\text{a}}.\vec{\text{b}}\big)^2$
  • C
    $|\vec{\text{a}}|^2+\big|\vec{\text{b}}\big|^2-2\big(\vec{\text{a}}.\vec{\text{b}}\big)$
  • D
    $|\vec{\text{a}}|^2+\big|\vec{\text{b}}\big|^2-\vec{\text{a}}.\vec{\text{b}}$
Answer
Correct option: B.
$|\vec{\text{a}}|^2\big|\vec{\text{b}}\big|^2-\big(\vec{\text{a}}.\vec{\text{b}}\big)^2$
$|\vec{\text{a}}|^2\big|\vec{\text{b}}\big|^2-\big(\vec{\text{a}}.\vec{\text{b}}\big)^2$
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MCQ 131 Mark
If $\vec{\text{a}},\vec{\text{b}}$ represent the diagonals of a rhombus, then:
  • A
    $\vec{\text{a}}\times\vec{\text{b}}=\vec{0}$
  • $\vec{\text{a}}.\vec{\text{b}}=0$
  • C
    $\vec{\text{a}}.\vec{\text{b}}=1$
  • D
    $\vec{\text{a}}\times\vec{\text{b}}=\vec{\text{a}}$
Answer
Correct option: B.
$\vec{\text{a}}.\vec{\text{b}}=0$
$\vec{\text{a}}.\vec{\text{b}}=0$
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MCQ 141 Mark
If $\hat{\text{i}},\hat{\text{j}},\hat{\text{k}}$ are unit vectors, then
  • A
    $\hat{\text{i}}.\hat{\text{j}}=1$
  • $\hat{\text{i}}.\hat{\text{i}}=1$
  • C
    $\hat{\text{i}}\times\hat{\text{j}}=1$
  • D
    $\hat{\text{i}}\times\big(\hat{\text{j}}\times\hat{\text{k}}\big)=1$
Answer
Correct option: B.
$\hat{\text{i}}.\hat{\text{i}}=1$
$\hat{\text{i}}.\hat{\text{i}}=1$
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