A student is investigating how the time for an electrical pulse to travel in a coaxial cable varies with the length of the cable. The pulse is reflected at one end of the cable. An oscilloscope is used to display the initial pulse and the reflected pulse. The trace on the oscilloscope is shown in Fig. 2.1. [Figure 2.1] The time t for the pulse to travel to the end of the cable and back is determined by measuring the distance d between the pulses on the screen, and then using the time-base and the relationship t = d × time-base. The initial length of the cable is L. A total length Z is removed from the cable and the experiment is repeated. It is suggested that t and Z are related by the equation v = 2(L-Z) / t where v is the speed of the pulse.