If you think to an electrical current the SI unit is ampere (A).
Relative intensity is measured in decibels and is abbreviated dB.
The abbreviation for electric intensity is " I " the intensity is measured in amps using an ammeter.
The intensity of earthquakes is measured on the Richter Scale.
Earthquake magnitude is measured using a number of differing scales including the Richter scale, the moment magnitude scale and the surface magnitude scale. Intensity is measured using he Modified Mercalli intensity scale.
intensity
decibels
It is luminous intensity measured in candelas
Sound intensity I is measured in watts per meter squared (W/m²). Look at the link: "Conversion of sound units (levels)".
Intensity is measured in Candela. Candela is its SI unit.
Intensity can be measured by converting units of electrical power in to decibels.
Reference sound intensity Io = 10^−12 W/m² (Threshold of human hearing). Reference sound intensity level LIo = 0 dB-SIL (Threshold of human hearing intensity level). The sound intensity I is measured in watts per meter squared. The sound intensity LI level is measured in decibels (dB).
Power P is measured in watts and intensity I (power per area) is measured in power per square meter if you think e.g. of sound.