You Might Wonder Why a Millibar Isn't Exactly 1/1000th of an Atmosphere.The

Multiple Choice

You might wonder why a millibar isn't exactly 1/1000th of an atmosphere.The unit is actually related to the old CGS units because atmospheric pressure is close to this unit.In CGS units 1 bar = 1000 dynes/cm2.Pressure is often incorrectly reported as kg/cm2,which is neither a legitimate pressure unit nor a standard SI unit (pressure is force/unit area,and kg are a mass unit,and SI units never mix kg and cm) .So let's straighten out your friends on these units.Standard air pressure in this incorrect unit is 1.034 kg/cm2.The weight of a kg at the earth's surface is 980,000 dynes.So what is standard air pressure in millibars?

A) 750 mb
B) 890 mb
C) 1013 mb
D) 1143 mb