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3-1.Vectors
easy
$\vec{A}$ is a vector quantity such that $|\vec{A}|=$ nonzero constant. Which of the following expressions is true for $\vec{A}$ $?$
A
$\overrightarrow{ A }\cdot \overrightarrow{ A }=0$
B
$\overrightarrow{ A } \times \overrightarrow{ A }<0$
C
$\overrightarrow{ A } \times \overrightarrow{ A }=0$
D
$\overrightarrow{ A } \times \overrightarrow{ A }>0$
(JEE MAIN-2022)
Solution
$|\overrightarrow{ A }| \neq 0$
$\overrightarrow{ A } \times \overrightarrow{ A }=|\overrightarrow{ A }||\overrightarrow{ A }| \sin 0^{\circ} \hat{ n }=0$
Standard 11
Physics
Similar Questions
If $\left| {\vec A } \right|\, = \,2$ and $\left| {\vec B } \right|\, = \,4$ then match the relation in Column $-I$ with the angle $\theta $ between $\vec A$ and $\vec B$ in Column $-II$.
Column $-I$ | Column $-II$ |
$(a)$ $\vec A \,.\,\,\vec B \, = \,\,0$ | $(i)$ $\theta = \,{0^o}$ |
$(b)$ $\vec A \,.\,\,\vec B \, = \,\,+8$ | $(ii)$ $\theta = \,{90^o}$ |
$(c)$ $\vec A \,.\,\,\vec B \, = \,\,4$ | $(iii)$ $\theta = \,{180^o}$ |
$(d)$ $\vec A \,.\,\,\vec B \, = \,\,-8$ | $(iv)$ $\theta = \,{60^o}$ |
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