Refection and transmission for two strings of different linear densities joined at their ends. On the left side of the junction is a primary string with the initial pulse, and on the right side of the junction is an auxiliary string. Two possibilities are presented with an auxiliary string of the larger linear density (above) and the smaller linear density (below). In both cases, part of the pulse is refected and part is transmitted at the junction of both strings. Note that the pulse velocity in the strings differs.