WHY IS ELECTRIC CURRENT A SCALAR QUANTITY?

Let’s proceed according to the definition of current. It is the flow of charge per unit time. When we say current is flowing in the circuit, we mean current is flowing from a high potential to a low potential within the circuit. It doesn’t say whether the current is flowing upwards or downwards or left or right. It actually doesn’t mean any direction in physical space.

Current doesn’t follow the vector addition law. Current flowing through different branches of a circuit cannot be added like a vector. We need the Kirchhoff’s laws to calculate it. Thus, current is a scalar quantity.