A level transmitter is scaled from 0 to 100 inches. The loop current is currently measuring 12mA. What is the actual water level in the tank?

The total span is 16mA (from 4 to 20). 12mA is exactly halfway between 4mA and 20mA (8mA span). Therefore, the process variable is at 50% of 100 inches, which is 50 inches.