Which statement is correct about a normal shock wave ?

Question

ATPL - Airline Transport Pilot license - Principles of Flight - Which statement is correct about a normal shock wave ?

QuizVDS · Accepted Answer

The airflow changes from supersonic to subsonic

QuizVDS · Answer

The airflow changes direction

QuizVDS · Answer

The airflow changes from subsonic to supersonic

QuizVDS · Answer

The airflow expands when passing the aerofoil

ATPL: Which statement is correct about a normal shock wave ?