Compressors, Gas Turbines and Jet Engines
Isothermal compression though most efficient, but is not practicable because

It does not increase pressure much
It requires very big cylinder
It is impossible in practice
Compressor has to run at very slow speed to achieve it

ANSWER DOWNLOAD EXAMIANS APP

Compressors, Gas Turbines and Jet Engines
Volumetric efficiency of a compressor without clearance volume

Increases with increase in compression ratio
Is not dependent upon compression ratio
Decreases with increase in compression ratio
May increase/decrease depending on compressor capacity

ANSWER DOWNLOAD EXAMIANS APP

Compressors, Gas Turbines and Jet Engines
The overall isothermal efficiency of the compressor is defined as the ratio of

Work required to compress the air isothermally to the actual work required to compress the air for the same pressure ratio
Isothermal power to the shaft power or B.P. of the motor or engine required to drive the compressor
Isentropic power to the power required to drive the compressor
Volume of free air delivery per stroke to the swept volume of the piston

ANSWER DOWNLOAD EXAMIANS APP