Part B: Does the discontinuity have a greater or lesser impedance to sound than
ID: 1997440 • Letter: P
Question
Part B:
Does the discontinuity have a greater or lesser impedance to sound than the surface above it?
The discontinuity has a lesser impedance to sound than the surface above it. The discontinuity has a greater impedance to sound than the surface above it. Problem 20.30 A sound wave created by an explosion at Earth's surface is reflected by a discontinuity of some type under Earth's surface. Sound travels at about 2500 m/s through the top layer of Earth. (Figure 1) Figure 1 of 1 Emitted pulse Reflected pulse 0 0.05 0.10 0.15 Time (s)Explanation / Answer
(A) distance from the surface to the discontinuity = speed of the sound in the earth surface * time of trevell
=2500 m/s * {0.08/2}
= 2500*0.04
= 100 m
(B) discontinuity have less impedance the the surface because sound treveed in the medium is greater than the sound trevelled in the surfe.