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

(A) Yes,a physical quantity can be a vector even if its magnitude is zero. Such a vector is called a null vector or zero vector.
For example,if a ball is thrown vertically upwards and returns to the thrower's hand,the displacement of the ball is zero. Since displacement is a vector quantity,this zero displacement is represented as a null vector.