Which extinguishing agent is most effective on a mattre……

单项选择题Which extinguishing agent is effective in combating an isoprene fire?（）

A.Dry chemicals
B.CO₂
C.Foam
D.All the above

单项选择题Which extinguishing agent is best for use on a magnesium fire?（）

A.Water
B.Sand
C.CO₂
D.Dry chemical

单项选择题Which characteristic of Halon is a disadvantage when it is used as a fire extinguishing medium?（）

A.Leaves a residue
B.Cost，relative to other agents
C.Breaks down while under prolonged storage
D.Conducts electricity

单项选择题Which characteristic is an advantage of Halon as a fire extinguishing medium?（）

A.Electrically non-conductive
B.Relatively inexpensive
C.Effective against chemicals containing an oxidizer
D.All of the above

单项选择题Which action is routinely performed at the annual servicing and inspection of a dry-chemical cartridge-operated portable fire extinguisher?（）

A.Insure the chemical is powdery
B.Replace the cartridge
C.Pressure test the discharge hose
D.Test the pressure gauge for proper operation