and then the downward component of the tension force pulls the ring back down. this movement of the ring produces a reflected pulse that is not inverted and that has the same amplitude as the incoming pulse.
finally, we may have a situation in which the boundary is intermediate between these two extremes. in this case, part of the energy in the incident pulse is reflected and part undergoes transmission-that is some of the energy passes through the boundary. for instance, suppose a light string is attached to a heavier string, as in figure 16.16. when a pulse traveling on the light string reaches the boundary between the two, part of the pulse is reflected and inverted and part is transmitted to the heavier string. the reflected pulse is inverted for the same reasons described earlier in the case of the string rigidly attached to a support.