Mark the correct statement :-

Establish the following vector inequalities geometrically or otherwise:

$(a)$ $\quad| a + b | \leq| a |+| b |$

$(b)$ $\quad| a + b | \geq| a |-| b |$

$(c)$ $\quad| a - b | \leq| a |+| b |$

$(d)$ $\quad| a - b | \geq| a |-| b |$

When does the equality sign above apply?

When $n$ vectors of different magnitudes are added, we get a null vector. Then the value of $n$ cannot be

When vector $\overrightarrow{ A }=2 \hat{ i }+3 \hat{ j }+2 \hat{ k }$ is subtracted from vector $\vec{B}$, it gives a vector equal to $2 \hat{j}$. Then the magnitude of vector $\vec{B}$ will be:

The vector $\overrightarrow{O A}$ where $O$ is origin is given by $\overrightarrow{O A}=2 \hat{i}+2 \hat{j}$. Now it is rotated by $45^{\circ}$ anticlockwise about $O$. What will be the new vector?