Electric current is the flow of electric charge in a conductor. In our daily lives, electric currents play a pivotal role. Whether in classrooms or homes, understanding the flow of current is essential. Scientifically, electric current refers to the movement of charge in circuits, sometimes carried by both ions and electrons. The unit of current, known as the Ampere (A), enables us to quantify this flow. Let’s learn about it all.
Definition of Current
Current is the flow of electric charge. In a conductor, it is the movement of electrons.
Current can be:
- Direct Current (DC): The flow of electric charge is constant in one direction.
- Alternating Current (AC): The flow of electric charge periodically reverses direction.
Formula for Current
The formula for current is defined by Ohm’s Law:
I = V/R
Where I represents the current, V is the voltage, and R is the resistance.
Read more about Ohm’s Law.
What is Unit of Current?
The unit of electric current is the Ampere (A) in the International System of Units (SI).
1A = 1Coulomb/second
What is 1 Ampere?
One ampere defined as the amount of electric charge passing through a given point in a conductor per unit of time i.e., 1A = 1C/s.
In simpler terms, it represents the flow of one Coulomb of charge per second.
SI Unit of Current
The SI (International System of Units) unit of electric current is the Ampere (A).
1A= 1C/s = 1 V/Ω
Note: In terms of magnetic field strength, 1 Ampere corresponds to a current that produces a magnetic field of 2 × 10-7 Tesla at a distance of 1 meter.
Unit of Current in Other Systems
Some other units of force in different systems are:
| System | Unit | Equivalent |
|---|---|---|
| SI (International System) | Ampere (A) | – |
| CGS (Centimeter-Gram-Second) | Statampere (statA) | 1 statA = 10-5 A |
| MKS (Meter-Kilogram-Second) | Abampere (abA) | 1 abA = 10 A |
Similar to other SI units, the ampere’s value can be adjusted by applying a prefix that scales it by a power of 10.
|
Unit of Current |
Symbol |
Equivalent in Amperes (A) |
|---|---|---|
|
Ampere |
A |
1 |
|
Milliampere |
mA |
0.001 |
|
Microampere |
μA |
0.000001 |
|
Nanoampere |
nA |
0.000000001 |
|
Kiloampere |
kA |
1000 |
|
Megaampere |
MA |
1,000,000 |
|
Gigaampere |
GA |
1,000,000,000 |
Conversion between Units of Current
In the following table, conversion factors for different units are given. These conversion factors can be multiplied to convert any unit to another unit.
|
From/To |
Ampere (A) |
Milliampere (mA) |
Microampere (μA) |
Nanoampere (nA) |
Kiloampere (kA) |
Megaampere (MA) |
|---|---|---|---|---|---|---|
|
Ampere (A) |
1 |
1000 |
1,000,000 |
1,000,000,000 |
0.001 |
0.000001 |
|
Milliampere (mA) |
0.001 |
1 |
1000 |
1,000,000 |
0.000001 |
0.000000001 |
|
Microampere (μA) |
0.000001 |
0.001 |
1 |
1000 |
0.000000001 |
0.000000000001 |
|
Nanoampere (nA) |
0.000000001 |
0.000001 |
0.001 |
1 |
0.000000000001 |
0.000000000000001 |
|
Kiloampere (kA) |
1000 |
1,000,000 |
1,000,000,000 |
1,000,000,000,000 |
1 |
0.001 |
|
Megaampere (MA) |
1,000,000 |
1,000,000,000 |
1,000,000,000,000 |
1,000,000,000,000,000 |
1000 |
1 |
How to use this Table for Conversion?
We can use the following table to convert between any two units as follows:
- To convert a value from one unit to another, multiply by the corresponding factor in the table.
For example, to convert 4 Ampere to Milliampere, multiply by 1000, resulting in 4000 mA.
- Conversely, to convert from Milliampere to Ampere, multiply by the factor in the Ampere row under the Milliampere column.
For example, converting 4 mA to Ampere involves multiplying by 0.001, resulting in 0.004 A.
Conclusion
In summary, the unit of current, measured in amperes (A), is fundamental to understanding electrical flow. Whether in circuits or daily life, recognizing its significance ensures safe and efficient use of electricity.
Sample Problem on the Unit of Current
Problem 1: Convert 2.5 Amperes to Milliampere.
Solution:
To convert 2.5 Amperes to Milliampere, use the conversion factor:
1 A = 1000 mA
So, to convert 2.5 A to mA:
2.5 × 1000 = 2500 mA
Therefore, 2.5 A is equal to 2500 mA
Problem 2: Convert 500 Milliampere to Amperes.
Solution:
To convert 500 Milliampere to Amperes, use the conversion factor:
1 A = 1000 mA
1 mA = 1/1000 A
So, to convert 500 Milliampere to Amperes:
500 mA / 1000 = 0.5 A
Therefore, 500 Milliampere is equal to 0.5 A.
Practice Problems on Unit of Current
Problem 1: Convert 3.2 Amperes to Microamperes.
Problem 2: Convert 800 Microamperes to Amperes.
Problem 3: Convert 1.5 Amperes to Statamperes.
Problem 4: Convert 2 Statamperes to Amperes.
Problem 5: Convert 10 Milliampere to Microamperes.
FAQs on Unit of Current
What is the Unit of Current in SI Units
The unit of electric current in the International System of Units (SI) is the Ampere (A).
How much is 1 Ampere?
One Ampere is the flow of one Coulomb of electric charge per second.
What is the SI unit of current?
The SI unit of current is ampere.
What is the formula of current?
The formula of current is: I = V/R
What are the basic two types of current?
The basic two types of current are alternating current (AC) and direct current (DC).
Which is the most common carrier in electric current?
Electrons are the carrier of current