# Physical Quantities and Their Units

**Level 2**requires school mathematics. Suitable for pupils.

## Table of contents

## Energy

**Symbol**: \(W\)**Unit of energy**: \(\mathrm{J}\) (Joule)**Example**: \( W ~=~ 30 \, 000 \, 000 \, \mathrm{J} \) is the energy released when one kilogram of coal is burned.

**Derived units of energy**

## Power

**Symbol**: \(P\)**Unit of power**: \(\mathrm{W}\) (Watt)**Example**: \( P ~=~ 2000 \, \mathrm{W} \) is the power of a kettle.

**Derived units of power**

## Pressure

**Symbol**: \(\mathit{\Pi}\)**Unit of pressure**: \(\mathrm{Pa}\) (Pascal)**Example**: \( \mathit{\Pi} ~=~ 100 \, 000 \, \mathrm{Pa} \) is the air pressure of the earth's atmosphere.

**Derived units of pressure**

## Charge

**Symbol**: \(Q\)**Unit of charge**: \(\mathrm{C}\) (Coulomb)**Example**: \(Q ~=~ 1.6 \cdot 10^{-19} \, \mathrm{C} \) is the charge of an electron.

**Derived units of charge**

## Voltage

**Symbol**: \(U\)**Unit of voltage**: \(\mathrm{V}\) (Volt)**Example**: \(U ~=~ 100 \, 000 \, 000 \, \mathrm{V} \) is the voltage between a thundercloud and the earth.

**Derived units of voltage**

## Resistance

**Symbol**: \(R\)**Unit of resistance**: \(\mathrm{\Omega}\) (Ohm)**Example**: \(R ~=~ 100 \, \mathrm{\Omega} \) is the resistance of an ohmic conductor to which 200 volts are applied and through which 2 amps flow.

**Derived units of resistance**

## Electric field

**Symbol**: \(E\)**Unit of electric field**: \( \frac{ \mathrm{V} }{ \mathrm{m} } \) (Volt per meter)**Example**: \(E ~=~ 1000 \, 000 \, \frac{ \mathrm{V} }{ \mathrm{m} } \) is the electric field between the bottom and top of a thundercloud.

**Derived units of the electric field**

## Magnetic field

**Symbol**: \(\class{violet}{B}\)**Unit of magnetic field**: \( \mathrm{T} \) (Tesla)**Example**: \(\class{violet}{B} ~=~ 20 \, \mathrm{T} \) creates a superconducting coil in a nuclear fusion reactor.

**Derived units of magnetic field**

## Capacitance

**Symbol**: \(C\)**Unit of capacitance**: \( \mathrm{F} \) (Farad)**Example**: \(C ~=~ 100 \, \mathrm{\mu}\mathrm{F} \) is the capacitance of a given capacitor.

**Derived units of capacitance**

## Inductance

**Symbol**: \(L\)**Unit of inductance**: \( \mathrm{H} \) (Henry)**Example**: \(L ~=~ 500 \, \mathrm{mH} \) is the inductance of a given coil with current flowing through it.

**Derived units of inductance**

## Thermal capacity (heat capacity)

**Symbol**: \(C\)**Unit of thermal capacity**: \( \frac{\mathrm{J}}{\mathrm{K}} \) (Joule per Kelvin)**Example**: \(C ~=~ 4190 \, \frac{\mathrm{J}}{\mathrm{K}} \) is the heat capacity of one liter of water.

**Derived units of heat capacity**