Question

What is electric current? Write its equation and unit.

Hint:

Remember: Current is a scalar quantity, but it has direction defined as the flow of positive charges (conventional current).

Answer 1

Step 1: Definition
Electric current is defined as the rate of flow of electric charge through a conductor in a given time. In metals, the charges are carried by electrons.

Step 2: Formula of Current
If $Q$ is the amount of charge flowing through a conductor in time $t$, then: \[ I = \frac{Q}{t} \]
Step 3: SI Unit of Current
The SI unit of electric current is the Ampere (A).
$1$ Ampere = Flow of $1$ Coulomb of charge in $1$ second.
$1 \, A = \frac{1 \, C}{1 \, s}$
Step 4: Equation by Ohm’s Law
According to Ohm’s Law, the current can also be written as: \[ I = \frac{V}{R} \] where $V$ is potential difference and $R$ is resistance.
Step 5: Importance in Daily Life
Electric current powers household appliances, lights, fans, refrigerators, etc.
It is the basis of modern technology — computers, communication systems, medical equipment all rely on controlled electric currents.
Final Answer:
Electric current is the rate of flow of charges. Its formula is $I = \tfrac{Q}{t}$ and its SI unit is Ampere (A).