1.1.1

Use of SI Units

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SI Base Units

SI base units are the standard units used to describe physical quantities in physics. They are:

Metre (m)

• The SI unit for distance (length).

Kilogram (kg)

• The SI unit for mass.

Second (s)

• The SI unit for time.

Ampere (A)

• The SI unit for electric current.

Kelvin (K)

• The SI unit for temperature.

Mole (mol)

• The SI unit for chemical mass.

Candela (cd)

• The SI unit for luminous intensity.

Combining SI Units

SI base units can be combined to form lots of other useful SI units:

Hertz (Hz)

• The SI unit for frequency.

Newton (N)

• The SI unit for force.

Joule (J)

• The SI unit for energy.

Watt (W)

• The SI unit for power.

Pascal (Pa)

• The SI unit for pressure.

Coulomb (C)

• The SI unit for electric charge.

Volt (V)

• The SI unit for electric potential difference.

Ohm (Ω.)

• The SI unit for electrical resistance.

Tesla (T)

• The SI unit for magnetic flux density.

Celsius (°C)

• Degrees Celsius are derived from the base SI unit for temperature (Kelvin).
• To convert between Kelvin and °C use the following equation:
• °C = K - 273.