In a gas turbine, the air charge is permitted to be compressed adiabatically by what factor, process, or condition?

Correct Answer: Option D — Speed of the process

Adiabatic compression occurs when heat transfer is negligible. In a gas turbine compressor, the process happens so rapidly that there is insufficient time for significant heat exchange with the surroundings. This high-speed operation allows the air charge to be compressed essentially adiabatically, maximizing the efficiency of the Brayton cycle.