If A→=2 and B→=4,then select incorrect statement.

A
If $\vec{A} . \vec{B} = 4$ , then angle between $\vec{A} and \vec{B}$ is 30°
B
If $|\vec{A} \times \vec{B}| = 4$ , then angle between $\vec{A} and \vec{B}$ is 30°
C
If $\vec{A} . \vec{B} = 8$ , then angle between $\vec{A} and \vec{B}$ is 0°
D
If $|\vec{A} \times \vec{B}| = 8$ , then angle between $\vec{A} and \vec{B}$ is 90°

Solution:

For(a) $cosθ \frac{\vec{A} . \vec{B}}{A . B} = \frac{4}{2 (4)} = \frac{1}{2} \Rightarrow θ = 60 °$
For(b) $sinθ = \frac{\vec{A} \times \vec{B}}{AB} = \frac{4}{2 (4)} = \frac{1}{2} \Rightarrow θ = 30 °$
For (c) $θ = 0 ° and for (d) θ = 90 °$

If $|\vec{A}| = 2$ and $|\vec{B}| = 4$ ,then select incorrect statement.

Solution:

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