SI Units

Unit of electric current. The ampere is a base unit.

The coulomb is the unit of electric charge. It is the quantity of electricity carried in 1 second by a current of 1 ampere.

The farad is the unit of electrical capacitance, the ability of a body to store an electrical charge.

where:

• C: coulomb
• V: volt
• W: watt
• J: joule
• N: newton
• : ohm
• Hz: hertz
• S: siemen
• H: henry

The henry is the unit of electrical inductance. It is the amount of inductance that causes a voltage of 1 volt when the current is changing at one ampere per second.

where:
- N: newton
- C: coulomb
- J: joule
- T: tesla
- W: watt
- V: volt
- F: farad
- : ohm

The hertz is the unit of frequency, which is one event (or cycle) per second.

Unit of energy.

It is the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre.
It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of 1 ohm for one second.

where:

• N: newton
• Pa: pascal
• W: watt
• C: Coulomb
• V: volt

Base unit for temperature. 0 degrees kelvin is absolute zero. A change of temperature by 1 kelvin corresponds to a change of thermal energy by , where is the Boltzmann constant.

, the approximate melting point of ice. A change in one degree celsius is equal to a change in one degree kelvin.

Measures the amount of a substance. One mole contains entities. The number of particles in a mole is Avogadro's Number.

One mole is defined as the number of atoms in 12 grams of Carbon 12.

The force which gives a mass of 1 kilogram an acceleration of 1 metre per second, per second.

The ohm is the unit of electrical resistance.

where:

• V: volt
• S: siemens
• W: watt
• F: farad
• H: henry
• J: joule
• C: coulomb

The pascal is the unit of pressure. The typical sea-level air pressure (1 atmosphere) is about 1013 hPa (101 300 Pa).

where:

• N: newton
• J: joule

The siemens is the unit of electric conductance, electric susceptance, and electric admittance. Conductance, susceptance, and admittance are the reciprocals of resistance, reactance, and impedance respectively.

where:

• : ohm

The tesla (T) is the unit of magnetic flux density, or B-field strength.

1. A particle, carrying a charge of one coulomb, and moving perpendicularly through a magnetic field of one Tesla, at a speed of one meter per second, experiences a force with magnitude of one newton.
2. A magnetic flux of 1 weber through a surface of one square meter
3. Since :
4. Since :
5. Since :

The volt is the unit of electrical potential, electrical potential difference (voltage), and electromotive force.

where:

• J: joule
• C: coulomb
• : ohm
• Wb: weber
• W: watt

The watt is the unit of power of radiant flux. It is equivalent to 1 joule per second, and is used to quantify the rate of energy transfer.

1. When an objects velocity is held constant at one metre per second against a constant opposing force of one newton, the rate at which work is done is one watt.
2. In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere flows across an electrical electrical potential of one volt flows across an electrical Electrical Fields#Electrical Energy. So the watt is equivalent to the volt-ampere
3. Using the previous equation and Ohm's law:

where:

• J: Joule
• N: newton
• V: volt
• : ohm

The weber is the unit of magnetic flux, equivalent to a volt-second.

where:

• V: volt
• T: tesla
• H: henry
• : ohm
• C: coulomb
• J: joule
• N: newton