04 – Waves at Boundaries – Transmission & Reflection Practice
Fixed to Concrete Wall
+
Tin Slinky
A
w
Lead Slinky
B
y
Thread
C
x
-
z
D
erect
inverted
The wave travels right in tin slinky – CREST (+)
1. Is it a Crest or Trough in:
a) x
(crest)
b) y
(crest)
c) z
(trough; reflected)
2. Will most of the energy be reflected or transmitted back in:
a) w
(reflected – low high density)
b) x
(reflected – hits fixed end)
c) y
(transmitted – high  low density)
3. Will the reflected wave be a crest (erect) or trough (inverted) in:
a) w
(inverted-trough; low high density)
b) x
(inverted-trough; hits fixed end)
c) y
(erect-crest; high  low density)
4. How will the velocity change at the boundary:
a) B
(slower)
b) C
(faster)
c) D
(about the same, a bit slower)
5. A wave has a length of 30.0 cm and a velocity of 2.5 cm/s. If it has a velocity of 3.70 cm/s
when it enters a new medium, what is the wavelength?
44cm
6. A wave is 2.30 m long before transmission. After transmission, it is travelling at 5.26 m/s
with a wavelength of 1.75 m. What is the velocity of the wave before transmission?
6.91m/s
7. A wave has a velocity of 4.00 m/s before transmission. How fast will it be going in the new
medium if its new wavelength is tripled?
12.0m/s
8. The frequency and wavelength of a transmitted wave is 25 Hz and 2.00 cm, respectively.
If the initial wave had a wavelength of 1.75 cm, what is the initial velocity?
44cm/s
9. A transmitted wave with a length of 2.00 m can travel 75.0 m in 30.0 s. If the wave was
travelling at 3.00 m/s in the initial medium, what was the wavelength?
2.40m