This paper uses a simple model to determine which of the two principal shocks at the end of a stellar jet, the bow shock or the Mach disk, emits more light at H-beta. It is found that the two shocks should have comparable surface brightness provided the jet and ambient medium densities do not differ by more than one to two orders of magnitude, and both shocks are radiative. The bow shock and Mach disk of a jet correspond to the bow shock and cloudlet shock, respectively, of a simple bullet/cloudlet model. A jet much denser than the surrounding medium appears similar to a bullet, with the leading bow shock dominating the visible emission. The model has been applied, with varying degrees of success, to four regions (HH 1, HH 34S, HH 47, and HH 101) containing extended bow-shaped structures. 71 refs.