We put an arrow mark ( `to`) to show the direction of current flow. Why is the current not a vector quantity?

Explanation

The arrow of current only denotes the sense of current in which direction the charge flows. But current does not obey the laws of vector addition and hence current is not a vector.

It is a scalar only. Consider a current flowing along ABCA. If current is a vector, the resultant should be zero. However, the current remains the same i. Thus, current is not a vector.