Reflection and Transmission of a Pulse

A pulse traveling along a stretched string encounters different terminations: a fixed end, a free end, and a junction to a second string with a different linear mass density. The simulation shows how the incident pulse splits into reflected and transmitted parts, with amplitudes given by the reflection (R) and transmission (τ) coefficients derived from continuity and slope conditions. The speed in each string depends on the tension and mass per length (v=√(T/μ)).

Students step through the demonstration using numbered buttons, select pulse shapes (Gaussian, sine, trapezium), and toggle a switch to view incident and reflected components separately. In step 5 a slider adjusts the ratio μ2/μ1, changing the impedance mismatch and thus the size and phase of reflected and transmitted pulses. Observing the trapezium shape makes the reversal of the reflected pulse evident.

Through this activity learners see how boundary conditions affect wave behavior, how impedance influences reflection and transmission, and how energy is conserved across the junction. The simulation reinforces concepts of wave speed, superposition, and the mathematical form of reflected and transmitted pulses.