ANS:A - more in the internal mouth piece

The contraction of a jet of liquid refers to the reduction in the diameter of the jet as it exits a nozzle or mouthpiece. In the context of fluid mechanics, when a liquid flows through a mouthpiece, it may experience contraction due to the geometry of the nozzle. In general, for an internal mouthpiece, the contraction of the jet is more pronounced compared to an external mouthpiece. This is because in an internal mouthpiece, the liquid flows through a constricted area before exiting into the open atmosphere. The internal mouthpiece provides more confinement to the flow, leading to a more significant contraction of the jet compared to an external mouthpiece where the flow transitions from a larger diameter to a smaller one, but without the additional constriction. Therefore, the correct option is: more in the internal mouthpiece