The position of a particle is given by, $\overrightarrow{\mathit{r}}=3\mathrm{t}\hat{\mathrm{i}}-4{\mathrm{t}}^2\hat{\mathrm{j}}+5\hat{\mathrm{k}}.$ Then the magnitude of the velocity of the particle at $t=2 \mathrm{s}$ is

Assertion: If $\overrightarrow{a}=\hat{\mathrm{i}}+2\hat{\mathrm{j}}-2\hat{\mathrm{k}}\text{,} \overrightarrow{b}=2\hat{\mathrm{i}}+\hat{\mathrm{j}}-\hat{\mathrm{k}}$, then $\left|\overrightarrow{a}\right|\ne \left|\overrightarrow{b}\right|$.

Reason: Two unequal vectors can never have same magnitude.

Choose the incorrect option.

The two vectors $\overrightarrow{\mathit{P}}$ and $\overrightarrow{\mathit{Q}}$ are drawn from a common point and $\overrightarrow{\mathit{R}}=\overrightarrow{\mathit{P}}+\overrightarrow{\mathit{Q}}$, then angle between $\overrightarrow{\mathit{P}}$ and $\overrightarrow{\mathit{Q}}$ is