The two vectors $\vec A = -2\widehat i + \widehat j + 3\widehat k$ and $\vec B = 7\widehat i + 5\widehat j + 3\widehat k$ are :-

If $\vec{P}+\vec{Q}=\overrightarrow{0}$, then which of the following is necessarily true?

The resultant of $\vec A$ and $\vec B$ makes an angle $\alpha $ with $\vec A$ and $\beta $ with $\vec B$,

If vectors $P, Q$ and $R$ have magnitude $5, 12$ and $13 $ units and $\overrightarrow P + \overrightarrow Q = \overrightarrow R ,$ the angle between $Q$ and $R$ is

If $\left| {{{\vec v}_1} + {{\vec v}_2}} \right| = \left| {{{\vec v}_1} - {{\vec v}_2}} \right|$ and ${{{\vec v}_1}}$ and ${{{\vec v}_2}}$ are finite, then

The vectors $\overrightarrow A $ and $\overrightarrow B$  lie in a plane. Another vector $\overrightarrow C $ lies outside this plane. The  resultant $\overrightarrow A + \overrightarrow B + \overrightarrow C$ of these three vectors