*On this page, We are going to learn about the full form of SI Unit and the meaning of SI Unit, As well as the meaning, definition, and acronym for SI Unit in different categories. So you should read this post till the end.*

**Full Form of SI Unit: International System of Units **

SI Unit Stands for ** Système International d’Unités**. which means an

**International system of units**. The International System of Units (or SI) is the modern metric system of units most used in science.

It is the modern version of the metric system, which was developed in the 1790s by the French scientist, Guillaume-François-Joseph de L’Hôpital.

**The international system of units** is the most widely used system of measurement in the world. The SI is a metric system, which is the measurement system of choice throughout the world because it is reliable, consistent, and accurate. The International System of Units is based on 7 basic units these are following-

Base units | unit | symbol |
---|---|---|

length | meter | m |

time | second | s |

mass | kilogram | kg |

electric current | ampere | A |

thermodynamic temperature | kelvin | K |

luminous intensity | candela | cd |

amount of substance | mole | mol |

### Names, and Symbols of SI Units in physics

The units are mainly divided into two parts –

**Base units –**The units which are used for the basic quantities are called fundamental units like length, mass, time, etc.**Derived Unit –**If a unit is a combination of two or more basic units, then such a unit is called a Derived Unit. in short, the derived units depend on the Base units.

For example, the unit of volume is *cubic centimeters* and the unit of area is *square centimeters*. If you look at these units carefully, then two basic units have been combined into one unit like cube and centimeter, square and centimeter, etc.

Unit of Area = Meter Meter = Meter2

Unit of Volume = Meter Meter Meter = Meter3

Unit of force = kg m/s2 = kg–m/s2 = newton

Unit of work = Newton meter = kg-meter2/second2

SI units hold a very important place for physical quantities in science. That is why we will learn about different SI Units, Names, and their Symbol.

Unite Name | S.I Unit |
---|---|

SI unit of Length | Symbol |

kilometer | km |

centimeter | cm |

millimeter | mm |

micrometer | μm |

nanometre | nm |

SI unit of Area | Symbol |

square kilometer | sq km, or km2 |

hectare | ha |

are | a |

square centimeter | sq cm, or cm2 |

SI unit of Volume | Symbol |

cubic meter | m3 |

cubic centimeter | cu cm, cm3, or cc |

SI unit of Capacity | Symbol |

kilolitre | kl |

liter | l |

centiliter | cl |

milliliter | ml |

microlitre | μl |

SI unit of Mass and weight | Symbol |

metric ton | t |

gram | g |

centigram | cg |

milligram | mg |

microgram | μg |

SI unit of Energy | symbol |

hertz (frequency) | Hz |

newton (force, weight) | N |

joule ( work, energy, quantity of heat) | J |

pascal (pressure, stress) | Pa |

watt (power) | W |

coulomb (electric charge) | C |

volt (electric potential difference) | V |

farad (electric capacitance) | F |

ohm (electric resistance, reactance) | Ω |

siemens (magnetic flux) | S |

weber (magnetic flux) | Wb |

tesla (magnetic induction) | T |

henry (inductance) | H |

lumen (luminous flux) | lm |

lux (illuminance) | lx |

### Types of the system of units

There are mainly four systems of units

**Units of the MKS method****Units of CGS System****Units of FPS method****Units of SI System**

In all types of methods, the units of the basic quantities are measured in different types of small and large values such as –

**1. Units of MKS System** – In this system, the units are written in the following way.

- length = meter
- mass = kilogram
- time = second

** 2. Units of CGS System –** In this system, the units are written in the following way.

- length = centimeter
- mass = grams
- time = second

** 3. Units of FPS System –** In this system, the units are written in the following way.

- length = feet
- mass = pound
- time = second

** 4.SI System of Units –** It is also called the International System. There are 7 units in this system which are of the following types –

- length = meter
- mass = kilogram
- time = second
- Light intensity = candela
- Electric current = ampere
- Temperature = Kelvin
- amount of substance = mole

### FAQs about SI Unit?

Now you might have got some ideas about the abbreviation, acronym, full form, and meaning of SI Unit. Also all popular full forms, acronyms, abbreviations, and SI Unit meanings and definitions.

#### What is the SI unit of surface tension?

The SI unit of Surface Tension is

**Newton per Meter or N/m**. surface tension is the measure of how much surface area is taken up by a liquid. It is a measure of the strength of the surface adhesion of a liquid to a solid or a gas.#### What is the SI unit of speed?

The S.I unit of speed is a

**meter**/second. speed can be calculate by**Speed (S) = distance(d)/time(t)**. The unit is used to measure the speed of an object or a motion.#### What is the SI unit of acceleration?

The SI unit of acceleration is defined as meters

**/second**. The SI unit of acceleration is often used to express the rate at which something is moving, such as when a car is moving, or when something is moving on a plane, train, or spacecraft.^{2}(m/s^{2})#### What is the SI unit of heat?

The

**joule**is the SI unit of energy, and energy is a synonym for heat. Heat is the sum of the kinetic energy of atoms or molecules of a substance.#### What is the S.I. unit of electric current

The SI unit of current is

**Ampere**. current is defined as The rate of flow of charge.#### What is the S.I. unit of Temperature?

The SI unit of current is

**kelvin**. degree Celsius (°C) is also another S.I. unit of Temperature. the relation between**kelvin**and degree Celsius is defined as**K = °C + 273**#### What is the SI unit of force?

The SI unit of force is

**Newton.**the formula of force is defined as**Force = mass * acceleration**.#### What is the SI unit of density

**kilogram per cubic meter**(kg/m^{3}) is the SI unit of density in physics. The mass contained in a unit volume of a substance is called the density of that substance. Density was discovered by the Greek scientist**Archimedes**.