LEVEL DETECTORS:

Liquid level measuring devices are categorized within two groups:  (a) direct method, and (b) inferred method. An instance of the direct method is the dipstick in your car that measures the height of the oil in the oil pan. An instance of the inferred method is a pressure gauge at the bottom of a tank that measures the hydrostatic head pressure from the height of the liquid.

 IDENTIFY the principle of operation of the subsequent categories of stages instrumentation:

a. Gauge glass

b. Ball float

c. Chain float

d. Magnetic bond

e. Conductivity probe

f. Differential pressure (?P)