Check definition, formula and solved examples based on Electric Current. It is one of the most important topics of Physics. Questions based on this topic are frequently asked in various school and competitive exams. Students having Physics as one of their subjects must have a clear understanding of Electric Current & other related topics. Here we have provided the definition, formula and some simple solved examples.
Electric Current Definition:
Electric Current is the rate of flow of charge in a conductor. The SI Unit of electric current is the Ampere. It is a scalar quantity.
Electric Current Formula:
I = V/R
I is the current (in ampere)
V is the voltage or potential difference (in volt)
R is the resistance (in ohm)
This formula is also the interpretation of ohm’s law.
Imagine a conductor through which a current I is flowing and let V be the potential difference between the ends of the conductor.
Then Ohm’s law states that
V ∝ I
or, V = R I
Where the constant of proportionality R is known as the resistance of the conductor. The SI units of resistance is ohm, and is represented by the symbol Ω. The resistance R not only depends on the material of the conductor but also on the dimensions of the conductor.
Question Based On Electric Current Formula:
Question: The voltage & resistance of a circuit are 20V and 2Ω respectively. What is the value of the current through the circuit?
R = 2 Ω
V = 20 V
As, V = I R
or I = V/R = 20/2 = 10 ampere.
Question: 2-ampere current is flowing through a conductor having 2-ohm resistance. Calculate the potential difference across a conductor?
I = 2 ampere
R = 2 ohm
Now, V = I R or V = 2 x 2 = 4 volt.