# Physical Quantities and Their Units

Level 2 (without higher mathematics)
Level 2 requires school mathematics. Suitable for pupils.
Updated by Alexander Fufaev on

## 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
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## Power

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

Derived units of power
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## 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
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## 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
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## 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
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## 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.

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## 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
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## 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
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## 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
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## 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.

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## 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
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