Plant Operator Selection System Test POSS 2 — Questions and Answers
Question 1: A pump moves 240 gallons of water in 8 minutes. How many gallons does it move in 15 minutes at the same rate?
- 360 gallons
- 420 gallons
- 450 gallons (Correct answer)
- 480 gallons
Correct answer: 450 gallons
The rate is 240 ÷ 8 = 30 gallons per minute; 30 × 15 = 450 gallons.
Question 2: Which type of valve is best suited for completely stopping or fully allowing flow, but NOT for throttling?
- Globe valve
- Gate valve (Correct answer)
- Needle valve
- Ball valve with fine adjustment
Correct answer: Gate valve
Gate valves are designed for fully open or fully closed positions and can be damaged by throttling.
Question 3: A gauge reads 35 psi. If 1 psi equals 2.31 feet of water head, what is the equivalent water head in feet?
- 66.0 ft
- 80.85 ft (Correct answer)
- 93.1 ft
- 101.5 ft
Correct answer: 80.85 ft
35 psi × 2.31 ft/psi = 80.85 feet of water head.
Question 4: A reading passage states that a plant must test cooling water pH every four hours. If a shift is 12 hours long, how many tests must be performed per shift?
- 2
- 3 (Correct answer)
- 4
- 6
Correct answer: 3
12 hours ÷ 4 hours per test = 3 tests per shift.
Question 5: On a bar graph showing monthly fuel oil consumption, January shows 8,200 barrels and June shows 3,700 barrels. What is the difference?
- 4,200 barrels
- 4,500 barrels (Correct answer)
- 4,700 barrels
- 5,100 barrels
Correct answer: 4,500 barrels
8,200 − 3,700 = 4,500 barrels difference between January and June.
Question 6: Two gears mesh together. Gear A has 20 teeth and rotates at 300 RPM. Gear B has 60 teeth. At what speed does Gear B rotate?
- 50 RPM
- 100 RPM (Correct answer)
- 150 RPM
- 900 RPM
Correct answer: 100 RPM
Speed ratio is inverse to tooth ratio: 300 × (20/60) = 100 RPM for Gear B.
Question 7: A safety data sheet (SDS) lists a chemical's flash point as 100°F. What does this mean for plant handling?
- The chemical explodes above 100°F
- The chemical can ignite from a spark at 100°F (Correct answer)
- The chemical boils at 100°F
- The chemical must be stored below 100°F to remain liquid
Correct answer: The chemical can ignite from a spark at 100°F
Flash point is the lowest temperature at which a substance can produce ignitable vapors when exposed to an ignition source.
Plant Operator Selection System Test POSS 2
A pump moves 240 gallons of water in 8 minutes.
How many gallons does it move in 15 minutes at the same rate?