Answer :

Solution :

Within the distance of a mean free path, the flow passes from a supersonic to a subsonic state, the velocity decreases suddenly and the pressure rises sharply. A normal shock is said to have occurred if there is an abrupt reduction of velocity in the downstream in course of a supersonic flow in a passage or around a body. Since, volume flow rate is constant, velocity at B is lower than velocity at A and pressure at location B is observed to be higher than that at an upstream location A. Therefore, it indicates the normal shock.