If \(|\vec{A}|=2\) and \(|\vec{B}|=4\), then match the relations in Column I with the angle \(\theta\) between \(\vec{A}\) and \(\vec{B}\) in Column II.

Column I Column II
(a) \(\vec{A}.\vec{B}=0\) (i) \(\theta=0^{\circ}\)
(b) \(\vec{A}.\vec{B}=8\) (ii) \(\theta=90^{\circ}\)
(c) \(\vec{A}.\vec{B}=4\) (iii) \(\theta=180^{\circ}\)
(d) \(\vec{A}.\vec{B}=-8\) (iv) \(\theta=60^{\circ}\)

Choose the correct answer from the options given below:

1. (a)–(iii), (b)-(ii), (c)-(i), (d)-(iv)
2. (a)–(ii), (b)-(i), (c)-(iv), (d)-(iii)
3. (a)–(ii), (b)-(iv), (c)-(iii), (d)-(i)
4. (a)–(iii), (b)-(i), (c)-(ii), (d)-(iv)
Subtopic:  Scalar Product |
 87%
Level 1: 80%+
Hints

Let two vectors be given as:
\(\vec{A}=a_{1} \hat{i}+b_{1} \hat{j}+c_{1} \hat{k}\) and \(\vec{B}=a_{2} \hat{i}+b_{2} \hat{j}+c_{2} \hat{k}.\)
Which of the following expressions correctly represents the angle \(\theta\) between the two vectors?
1. \(\theta=\cos ^{-1}\left(\dfrac{a_{1} a_{2}+b_{1} b_{2}+c_{1} c_{2}}{\sqrt{a_{1}^{2}+b_{1}^{2}+c_{1}^{2}} \sqrt{a_{2}^{2}+b_{2}^{2}+c_{2}^{2}}}\right) \)
2. \(\theta=\sin ^{-1}\left(\dfrac{a_{1} a_{2}+b_{1} b_{2}+c_{1} c_{2}}{\sqrt{a_{1}^{2}+b_{1}^{2}+c_{1}^{2}} \sqrt{a_{2}^{2}+b_{2}^{2}+c_{2}^{2}}}\right) \)
3. \(\theta=\cos ^{-1}\left(a_{1} a_{2}+b_{1} b_{2}+c_{1} c_{2}\right) \)
4. \( \theta=\sin ^{-1}\left(a_{1} a_{2}+b_{1} b_{2}+c_{1} c_{2}\right) \)
Subtopic:  Scalar Product |
 84%
Level 1: 80%+
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The angle (in degrees ) between the resultant of \(2 \overrightarrow{q}-2 \overrightarrow{p}\) and \(2 \overrightarrow{q}+2 \overrightarrow{p}\) with \(\overrightarrow{q} \) is:
1. \(0^\circ\)
2. \(30^\circ\)
3. \(45^\circ\)
4. \(60^\circ\)
Subtopic:  Scalar Product |
 71%
Level 2: 60%+
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