The change in a vector may occur due to .....

If $\alpha, \beta$ and $\gamma$ are the angles made by a vector with $x, y$ and $z$ axes respectively,then $\sin ^2 \alpha + \sin ^2 \beta =$

If the magnitude of a physical quantity is zero,can it be a vector? Give a suitable example.

$A$ vector has a magnitude $x$. If it is rotated by an angle $\theta$, then the magnitude of the change in the vector is $nx$. Match the following two columns:

Column $I$	Column $II$
$(A)$ $\theta=60^{\circ}$	$(p)$ $n=\sqrt{3}$
$(B)$ $\theta=90^{\circ}$	$(q)$ $n=1$
$(C)$ $\theta=120^{\circ}$	$(r)$ $n=\sqrt{2}$
$(D)$ $\theta=180^{\circ}$	$(s)$ $n=2$

The angle made by a vector $\vec{B} = 3 \hat{i} + 2 \hat{j} + 4 \hat{k}$ with the $y$-axis is:

Find the unit vector of a vector whose coordinates are $(8, 6)$.