Question

What is electric current? What is its SI unit? Is current a scalar or vector quantity? What are the conventions regarding the flow of current? Name the instrument that is used for measuring the current flowing through the circuit?

Answer 1

Concept Used: Electric Current

Step 1: Electric Current and its SI unit:

Electric Current is the flow of electric charge or electron in a circuit i.e. rate of flow of electrons in a conductor. The SI unit of electric current is ampere (A) and electric current is represented by the letter $\mathrm{I}$

Step 2: Current, a scalar or vector quantity:

1. A scalar quantity has magnitude only, A vector quantity has both magnitude and direction.
2. Also, there are other factors that determine the quantity as vector or scalar.
3. A vector quantity should obey the law of vector addition.
4. In the case of electric current, it has both magnitude and direction but the sum will be an algebraic sum, not the vector sum.
5. Therefore, an electric current is a scalar quantity.

Step 3: Conventions regarding the flow of current:

By conventions, the direction of flow of current is taken from the positive terminal to the negative terminal of the battery. which is opposite to the flow of electrons.

Step 4: Instrument:

The instrument used to measure electric current flow in a circuit is Ammeter and it is calibrated in ampere.