Electric Current Formula: Definition, Formula & Solved Questions

Electric Current can be defined as the continuous flow of electrons in an electric circuit. It is referred to as the rate of flow of negative charges of the conductor. When the potential difference is applied across the wire or terminal, there is a movement of the electrons. In simpler terms, electric current is the rate of change of electric charge through a circuit. Electric Current is represented by the symbol I and its SI unit is Ampere. The electric current is related to the electric charge and the time.

Key Terms: Electric Current, Electrons, Electric Flow, Electric Charge, Electric Circuit, Conductor, Potential Difference, Resistance, Amperes, Atoms, Ampere

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What is Electric Current?

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There are a large number of free electrons in the electricity-conducting material which move from one atom to the other randomly. The free electrons will move towards the positive terminal of the cell when the potential difference is applied across a wire or terminal. Thus, electric current is basically this continuous flow of electrons. The electric current is measured in Ampere (SI Unit of Current).

The conventional direction of an electric current is the direction in which a positive charge will move, thus, the current flowing in the external circuit is directed away from the positive terminal of the cell to the negative terminal of the cell.

Electric Current

Discover about the Chapter video:

Current Electricity Detailed Video Explanation:

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Types of Electric Current

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Electric current can be classified into two types based on the flow of electric charge: 

• Alternating Current: The charges flow in both directions in this type of Current.
• Direct Current: In a direct current, the charges flow in one direction.

AC and DC Current

Read More: Difference between AC and DC

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Electric Current Formula

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The current formula is derived from Ohm’s Law. Using Ohm’s Law, the Electric Current Formula is as follows: 

I = V/R

Where

• I represent Electric Current in Ampere
• V is the Potential Difference in Volt
• R is the Resistance in Ohm (Ω)

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Solved Examples on Electric Current Formula

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Example 1: An electric heater in a house has a resistance of 70 Ω and a potential difference of 220 V. What will be the magnitude of the current flowing through the heater?

Solution: Resistance (R) = 70 Ω

Voltage (V) = 220 

The electric current formula as per the Ohm's Law is given as 

I = V / R

I = 220 / 70

I = 3.1428 Amperes

Example 2: The electric current flowing in an electric circuit is given as 50Amp and the resistance of the wires is 14Ω. What will be the potential difference as per the current formula?

Solution: Given that

I = 50 A 

R = 14Ω

Using the Electric Current Formula as per Ohm's Law

I = V/R

50 = V/14

V = 50 × 14

V = 700 Volts

Thus, the potential difference is 700 V. 

Also Read:

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Things to Remember

• Electric current is defined as the rate of change of electric charge through a circuit. 
• Electric Current relates to the voltage and resistance of the circuit. It is a scalar quantity. 
• The electric current is represented by the symbol I and its SI unit is Ampere.
• According to Ohm’s Law, the electric current formula is: I = V/R
• An electric wire carries a current of 1 ampere when a charge flows through it at the rate of one coulomb per second.

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Previous Year Questions 

•  When the switch S , in the circuit shown, is closed, then the value of current ii will be…. [ JEE Main 2019]
• The Wheatstone bridge shown in Fig. here, gets balanced when the carbon resistor… [JEE Main 2019]
• In the given circuit the cells have zero internal resistance…. [JEE Main 2019]
• The currents I2,I3 and I6,respectively, are….[JEE Main 2019]
• A d.c. main supply of e.m.f. 220V is connected across a storage battery of e.m.f. 200V through a resistance of 11 Ω…... [JEE Main 2014]
• The percentage change in its electrical resistance if its volume remains unchanged is…. [JEE Main 2019]
• three resistors 3Ω,9Ω and 9Ω and a capacitor….. [JEE Main 2013]
• If now we hav.e to change the null point at 9th wire, what should we do?… 
• The electrical permittivity and magnetic permeability of free space are… 
• In the given circuit, an ideal voltmeter connected across the 10Ω resistance reads 2V . The internal resistance rr, of each cell is….[JEE Main 2019]
• In the experimental set up of metre bridge shown in the figure, the null point is obtained at a distance…. [JEE Main 2019]
• Correct set up to verify Ohm’s law is….[JEE Main 2013]
• The resistance between any two terminals is when connected in a triangle is…. [ NEET 1993 ]
• potential drop through 4Ω resistor is… [ NEET 1993 ]
• The potential difference per unit length of the wire will be… [ NEET 1999 ]
• Value of R for which the power delivered in it is maximum is given by... [ NEET 1992 ]