While attempting to read a tank level...

🔍 Key Concepts

• How a mercury tank level gage works (tank liquid pressure is transmitted through a gage line to the mercury column) • What would cause a sudden loss of pressure in that line versus a slow or steady change • Difference between problems in the gage system (piping, chambers) and conditions inside the tank (free surface, calibration, trapped air)

💭 Think About

• Ask yourself: what physical change would make the pressure on the mercury suddenly drop so the column falls quickly, even though the tank level itself hasn’t suddenly changed? • Which choices describe an issue with the instrument or its piping, and which describe an issue with the tank contents or measurement accuracy? • If the tank level changed, would it normally move the mercury column gradually or suddenly the way the question describes?

✅ Before You Answer

• Identify which options refer to the gage line or measuring system itself rather than to the tank’s internal behavior • Consider whether each option would cause a rapid drop in reading or a gradual/erratic change • Make sure your choice explains a sudden loss of pressure on the mercury column, not just an inaccurate or fluctuating reading

While attempting to read a tank level indicator, the mercury column drops rapidly. This may indicate __________.

a leak in the gage line

free surface effect in the tank

an improperly calibrated gage

excess air in the balance chamber

🔍 Key Concepts

💭 Think About

✅ Before You Answer