Set 17 Marine engineering Knowledge (Motor) online MCQ questions with answers

1. It is a known fact that centrifugal pumps require priming for pumping liquids , as they cannot handle air and will lose suction due to air entry . But on the other hand T/Cs use centrifugal compressors for supercharging . Which of the following do you think makes a centrifugal compressors to pump air and behave differently than the centrifugal pumps?
choose one Presence of air cooler Presence of Labyrinth seal High speed of rotation , very fine internal clearences and large impeller diameters Difference in principle of operation

2. If an operating auxiliary boiler has a water pH reading of 7, you should
choose one bottom blow the boiler treat the water with caustic soda treat the water with chemical scavengers reduce the water alkalinity to recommended readings

3. Even if there is an oil mist concentration inside a crankcase, and there is also a hot spot, crankcase explosion will only take place when_________________
choose one The hot spot provides the ignition temperature for the oil mist concentration When the oil mist - air mixture is in the flammable range Both A and B None of the abov

4. Which of these fuel oil impurities can cause maximum abrasive damage?
choose one Weter Ash Catalytic Fines Sodium

5. Steam temperature control for the ESD boiler is achieved by :
choose one Fitting a de-superheater between 1st & 2nd passes of superheater Fitting an attemperator between 1st & 2nd passes of superheater Bypassing the superheater Gas dampers in boiler uptake

Score =
Correct answers: