Which of the following elements is doped to a fiber amplifier in an optical fiber communication system?

$A$ vector has magnitude and direction. Does it have a location in space? Can it vary with time? Will two equal vectors $a$ and $b$ at different locations in space necessarily have identical physical effects? Give examples in support of your answer.

$A$ particle has a displacement of $12 \, m$ towards east,$5 \, m$ towards north,and $6 \, m$ vertically upward. The magnitude of the resultant displacement is ......... $m$.

Give three properties which have different magnitudes and also have different directions.

Can you associate vectors with $(a)$ the length of a wire bent into a loop,$(b)$ a plane area,$(c)$ a sphere? Explain.

If $|\vec{A}+\vec{B}|=|\vec{A}-\vec{B}|$,then the angle between vector $\vec{A}$ and $\vec{B}$ is: (in $^{\circ}$)