We know that the invention of electric current revolutionized living and lifestyle. It is the fundamental source to power many devices like fans to complex devices like boilers and heaters. Current is defined as the flow of electrical charge carriers. In this article, let us learn what is current, types of current, formula, current density along with solved examples.

**Table of Contents:**

- Current Definition
- Types of Current
- Direct Current
- Alternating Current
- What is Current Density
- Current Density Formula
- Solved Problem on Current Density
- Frequently Asked Questions – FAQs

## Current Definition:

We can define current as the flow of electrically charged particles, mostly in those atoms which are electron-deficient. The standard symbol of current is capital **I**. The standard unit of current is ampere and it is denoted by **A**. Conversely, a current of one ampere is one coulomb of charge(6.24 x 10^{18} charge carriers) going past a given point per second. According to Physicists, Current is considered to move from relatively positive to negative points, and this is known as conventional current. Electrons are known to be the common negatively-charged carriers and circulate from relatively negative to positive points. In this article, we will learn about the concepts of Current Density in a detailed manner.

## Types of Current

*The current can be divided into two types.*

### Direct Current:

- Direct current travels towards the same direction at all points, although the instantaneous magnitude can differ.
- An example of DC is the current generated by an electrochemical cell.

### Alternating Current:

- The flow of charge carriers is towards the opposite direction periodically in an alternating current.
- The number of AC cycles per second is known as frequency and calculated in Hertz.

To know more about current flow in detail, click on the video below.

## What is Current Density?

The amount of electric current traveling per unit cross-section area is called as current density and expressed in amperes per square meter. More the current in a conductor, higher will be the current density. However, the current density alters in different parts of an electrical conductor and the effect takes place with alternating currents at higher frequencies.

Electric current always creates a magnetic field. Stronger the current, more intense is the magnetic field. Varying AC or DC creates an electromagnetic field and this is the principle based on which signal propagation takes place.

Current density is a vector quantity having both a direction and a scalar magnitude. The electric current flowing through a solid having units of charge per unit time is calculated towards the direction perpendicular to the flow of direction.

It is all about the amount of current flowing across the given region.

## Current Density Formula

The formula for Current Density is given as,

**J = I / A**

Where,

I = current flowing through the conductor in Amperes

A = cross-sectional area in m^{2}.

Current density is expressed in A/m^{2}.

## Solved Problem on Current Density

*Determine the current density when 40 Amperes of current is flowing through the battery in a given area of 10 m ^{2}.*

**Solution:**

It is given that,

I = 40 A,

Area = 10 m^{2}

The current density formula is given by,

J = I / A

= 40 / 10

J = 4 A/m^{2}.

Hope you have learnt what is current and current density. To know about the current density of copper, Ohm’s Law, and current density along with other related concepts visit BYJU’S.

## Frequently Asked Questions – FAQs

### What is current?

### What are the types of current?

The following are the types of electric current:

- Direct Current
- Alternating Current

### What is meant by current density?

The amount of current traveling per unit cross-section area is known as current density and expressed in amperes per square meter.