67) The overall efficiency of the compressed air system is the

ratio of shaft output of the air motor to the shaft input to the compressor

ratio of shaft input to the compressor to the shaft output of air motor

product of shaft output of air motor and shaft input to the compressor

none of the above

Answer is:

ratio of shaft output of the air motor to the shaft input to the compressor

Correct

Incorrect

Answer is:

isothermal

polytropic

isentropic

any one of these

Answer is:

low frontal area

higher thrust

high pressure rise

none of these

Answer is:

The flow of air is parallel to the axis of the compressor.

The static pressure of air in the impeller increases in order to provide centripetal force on the air.

The impeller rotates at high speeds.

The maximum efficiency is higher than multi-stage axial flow compressors.

Answer is: