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Electric Current

Last Updated : 15 May, 2024
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Electric current is the type of energy that is responsible for the working of modern-day society. We define electric current as the flow of electric charge. Electric current is used to power our everyday life, we use mobiles, computers, ACs, TVs, Fridges, etc in our daily life all these are powered by electric current. Electric current is the flow of the electron in the circuit that allow the electric energy to flow which changes into a different form of energy accordingly.

In this article, we will learn about Electric Current, its unit, properties of electric current, Ohm’s law, the effect of electric current, etc, and others in detail.

What is Electric Current?

The flow of electric charges is known as electric current. In earlier times, it was considered that correct flow was due to the movement of positive charges from the positive terminal to the negative terminal. But after the discovery of electrons, the conventional wisdom was proven wrong as the positive charge is nothing but the deficiency of the electron.

Now, scientists know that correct itself is generated due to the movement of negative charges (electrons), electron flow from the negative terminal of the system to the positive terminal, which is known as Electron flow, and unlike electrons, current flows in the opposite direction i.e., from the positive terminal to negative terminal, which is also known as Conventional Current flow.

Electric Current Definition

Electric current is the flow of electric charge through a conductor. It is a measure of the rate at which electric charge passes through a particular point in a circuit. In simpler terms, electric current is the movement of electrons or ions in a closed circuit, typically resulting from the presence of a voltage difference across the circuit.

Representation of flow of electron and flow of current in a closed circuit

The best way to imagine current flowing in a circuit is by imagining the flow of liquid inside a pipe from a higher point to a lower one, the liquid represents current, and the difference in the heights of the extreme end of the pipe represents the difference in potential causing the current to flow if the pipe is twisted at some point the flow of the liquid will slow down, that represents the resistance offered by the conductor that reduces the current.

Materials that easily let electrons move from one place to another are called conductors. These materials make it easy for electric charge to pass through them because electrons can move around freely. When electrons move through a conductor, it creates electric current. The force needed to make the current flow through a conductor is called voltage.

Examples of conductors are the human body, salty water, and metals like iron, silver, and gold.

On the other hand, insulators are materials that don’t let electrons move around freely. This means electric charge can’t flow easily through them. Because of this, the charge usually stays put and doesn’t spread out evenly over an insulator‘s surface.

Examples of Insulators include plastic, wood, and glass.

Check: Electric Current in Conductors

Electric Current Formula

The electric current can be represented as the rate of flow of electric charge (q) which mathematically can be represented as follows: 

Formula for Current , I=q/t

Unit of Electric Current

As Electric Charge and Time come under the Fundamental quantities and their units are respectively Coulomb and second. So by the definition of Electric Current, its unit is Coulomb/second.

  • In the SI Unit of Electric Current is Ampere (A).
  • In the CGS system, the unit of Electric Current is Biot or sometimes called an Abaampere.

Fact: Silver is the best at conducting electricity.

Check: Electric Current Formula

What Is Electromotive Force or EMF?

Normally, in a conductor, Electrons are present, and they are not stationary, they keep on moving in random directions, and due to their randomness, the overall displacement of all electrons becomes zero, and hence, no current is produced. In order to produce current, some external force is required to align electrons in one direction and make them move in that one direction, this external force is known as Electromotive Force and is also famous as EMF. It is nothing but the voltage applied to produce current.

Types of Electric Current 

There are two types of electric current, that are,

  • Alternating Current
  • Direct Current

Alternating Current

Electric current with its direction and values keep changing is known as Alternating Current. The values of AC in one direction increase from 0 to peak value then falls down to 0 again, then in opposite direction increase from 0 to peak value then come back to 0. 

As electric current goes from 0 to peak in one direction and the same in the opposite direction, it behaves like a wave more specifically a sine wave and it has some frequency. For example, in India, the grid provides 60 Hertz 220 Volts AC but in America, their grid provides 120 Volts 50 hearts AC.

Direct Current

Electric current with the same direction always is known as Direct Current. As the direction of DC remains the same, so its frequency is 0. 

Check Types of Current

Conventional Current Flow Vs Electron Flow

Aspect Conventional Current Flow Electron Flow
Description Traditional description of electric charge movement Modern and accurate description of electric charge movement
Direction of Current Positive terminal to negative terminal of voltage source Negative terminal to positive terminal of voltage source
Basis Established before the discovery of the electron Based on the movement of electrons through conductors
Charge Movement Positive charges are considered to move in the direction of current Negatively charged electrons move in the direction of current
Accuracy Historically used but not reflective of actual charge movement Reflects the actual movement of charge in a circuit

Properties of Electric Current

Various properties of Electric Current are :

  • Current is due to the Flow of electrons in the circuit.
  • Electric current can be categorized as AC and DC in nature, where DC is the direct current that flows in only one direction, DC is used in low-voltage applications, aircraft applications, etc. AC is known as alternating current, and it flows in both directions alternatively, AC is the current that comes in our houses, and the appliances work on AC.
  • The electric current in a circuit can be controlled by introducing resistance to the circuit.
  • The unit of Electric current is Amperes (A). 1 Ampere can be defined as the flow of 1 coulomb of charge in 1 second.
  • Electric current flows from Higher potential to Lower Potential in a circuit (from positive terminal to negative terminal) also known as the conventional current flow direction.

Ohm’s Law

German physicist Georg Simon Ohm stated that the current flowing in a wire is directly proportional to the voltage drop across it. According to Ohm’s Law, the current flowing through a wire is directly proportional to the voltage applied at the ends of the wire provided that the temperature and conductivity remain the same.

V ∝ I

Upon removing the proportionality sign, a proportionality constant is introduced known as Resistance.

Ohm's Law

Where,

  • V is Voltage at the ends of conductor
  • R is Resistance offered by the conductor
  • I is Current through the wire

Ohm’s law can be illustrated using the following illustration,

Illustration representing Ohm's Law

Effects of Electric Current

There are different effects that can be noticed due to the flow of electric current in a wire, for example, when current passes through a resistor, the resistor has a property of resisting which does not let the whole current pass but since energy can neither be created nor destroyed, it is converted in heat energy and is released in the form of heat, this effect is called as the heating effect of current. Similarly, we have the magnetic and chemical effects of electric current.

1. Chemical Effect of Electric Current

When Electric current is passed through a which is conducting in nature, the solution breaks in its respective ions, and effects are seen visibly. The major effects that are prominent,

  • The color of the solution may change.
  • The deposition of metal at the electrodes may be seen.
  • There can be the formation of gas bubbles at the electrodes.

2. Magnetic Effect of Electric Current

Electric current is nothing but the motion of electrons, and it is known, when charges are stationary, they create Electric Field but when charges are in motion, they create a Magnetic field. When current is passed through a wire and a metallic sheet is placed there with a needle, the needle will be deflected due to the presence of a magnetic field which is produced by the electric current. One of the biggest applications of the Magnetic effect of electric current is Electromagnets, they are formed with the help of passing current.

3. Heating Effect of Electric Current

When current flows in a conductor, heat energy is produced and released from the conductor and the amount of effect depends upon the resistance offered by the conductor. If the conductor has to offer high resistance, it simply means that it shall not allow most of the current to flow but due to the conservation of energy (energy can neither be created nor destroyed), current that could not pass is converted into heat and the phenomenon is known as the Heating effect of current. The formula for heat energy is given by,

Formula for Heating Effect of Electric Current

Where,

  • H is Heat energy released
  • I is current flowing in the conductor
  • R is Resistance offered by the conductor
  • T is Time for which the current was flowing in the conductor

Applications of the heating effect of current involve Electric Irons, Electric Heaters, filament lamps, Electric kettles, etc.

Read More,

Solved Examples of Electric Current

There are some solved examples of electric current for better understanding given below :

Example 1: In a conductor, 10 Coulombs of charge flow for 5 seconds, determine the current produced.

Solution

The current in a circuit is given by,

I = q/t

⇒ I = 10/5 Amperes

⇒ I = 2 Amperes

Therefore, 2 amperes of current flows in the circuit.

Example 2: In the circuit given below, Find the current flowing through the circuit.

Example 2

Solution

In the figure provided, it is clear that there are two resistances, and they are in series.

R = R1 + R2

⇒ R = 2+ 2

⇒ R = 4 ohms

From Ohms Law,

V = IR

⇒ I = V/R

⇒ I = 20/4

⇒ I = 5 Amperes 

Example 3: What is the Heat energy produced when 2 amperes of current is flowing in a circuit for 5 seconds having an overall resistance in the circuit of 4 ohms?

Solution

Heat Energy Produced is given by,

H = I2RT

⇒ H = (2)2×4 × 5

⇒ H = 16 × 5

⇒ H = 80 Joules

Therefore, 80 Joules heat is produced in the circuit.

Electric Current – FAQs

What is electric current?

Electric current is the flow of electric charge through a conductor, typically measured in amperes. It occurs when there is a voltage difference across a conductor.

What is SI Unit of Electric Current?

SI Unit of Electric Current is Ampere.

Define Ampere.

In a conductor if 1 Coulomb of charge passes in 1 second of time, then we say 1 Ampere current is flowing through that conductor.

How does electric current work?

Electric current flows when electrons move through a conductor, such as a wire, driven by a voltage difference applied across it. This movement is typically from a negative to a positive terminal.

What are the types of electric current?

There are two main types: direct current (DC), where the flow of electricity is in one direction, and alternating current (AC), where the current reverses direction periodically.

What are the effects of electric current?

Electric current can produce several effects, notable among them are heating effect, magnetic effect, and chemical effect, each playing a crucial role in various applications like heating, motors, and batteries.

How is electric current used in everyday life?

Electric current is essential in powering household appliances, lighting, heating systems, and in larger scales, it drives machinery and public transport systems.

What are common safety tips for handling electric current?

Safety tips include avoiding water when handling electrical devices, using insulated tools, not overloading circuits, and ensuring all electrical installations comply with local safety standards.

An Instrument Detects Electric Current is known as________.

Instrument for measuring electric current is known as Ammeter.



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