Properties of waves switching mediums?

In summary, waves will not always get larger when they pass from a denser medium to a less dense medium. This has to do with the amount of energy that is present in the original wave. Frequency also remains constant when a wave changes mediums. This is due to the constant relationship between wavelength and frequency. Speed changes when only wavelength changes. This occurs because the energy in the wave is being dispersed more throughout the medium.
  • #1
waffle23
2
0
Why is it that when a wave (say transverse) passes from a dense medium (say a spring) into a less dense medium, the transmitted wave is not always larger than the original. I'm not sure, but I believe it has to do with the amount of energy in the original wave, or I'm just completely wrong.

Also, why is it that frequency remains constant when a wave changes mediums and is this why speed changes since only wavelength changes?

I might ask more questions later. I know a lot of this is info I could just find out from a teacher, but I'm really pressed for time this week, missed last friday, and have a test tuesday.

Thanks.
 
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  • #2
First of all, please try not to miss class. If you do, make sure someone will get class notes for you, and offer to do the same (reciprocity).

waffle23 said:
Why is it that when a wave (say transverse) passes from a dense medium (say a spring) into a less dense medium, the transmitted wave is not always larger than the original. I'm not sure, but I believe it has to do with the amount of energy in the original wave, or I'm just completely wrong.
It has to do with momentum as well as energy. At an interface, with dissimilar properties, some energy will be transmitted, and some energy will be reflected.

waffle23 said:
Also, why is it that frequency remains constant when a wave changes mediums and is this why speed changes since only wavelength changes?
Relationship between speed, frequency and wavelength in water - http://www.gcsechemistry.com/pwav5.htm
 
  • #3
Thanks.

Yes, I got class notes (I was not planning on missing class; I went home sick, and believe me - I don't like missing physics as it's the only class I can stay fully awake during:wink: ), but this situation was hazy to me and I am still slightly unclear on it. Perhaps I am not explaining my problem correctly. I am aware of how the reflection and transmissions occur in general, but I am unsure of why when a wave passes from a dense medium into a less dense medium, sometimes the transmitted wave is larger, and other times it does not get larger. What specifically causes this to happen (it being a "sometimes" situation rather than an "always" one)? In my notes it states word for word that:

"A pulse originates in the more dense medium. As the pulse travels into the less dense medium, the speed of the transmitted pulse increases, its size increases (not always), and it's orientation...

So I know that when dealing with dissimilar mediums, some energy is transmitted and some is reflected (which is always a given), but why is it that in this specific situation, the "not always" scenario occurs when going from more dense to less dense and what conditions must occur for this to happen. This is also confusing since no constraint such as "not always" is given to a pulse originating in a less dense medium to a more dense medium.

Hopefully I explained it better that time. Thanks again for the help.
 

1. What are the properties of waves?

Waves have several properties, including amplitude, wavelength, frequency, and speed. Amplitude is the height of a wave, while wavelength is the distance between two consecutive peaks or troughs. Frequency is the number of complete waves that pass a point in a given time, and speed is the rate at which the wave travels.

2. How do waves behave when they switch mediums?

When waves switch from one medium to another, they can either be transmitted, reflected, or refracted. Transmission occurs when the wave passes through the new medium without changing direction or losing energy. Reflection happens when the wave bounces off the surface of the new medium. Refraction occurs when the wave bends as it passes through the new medium due to a change in speed.

3. What factors affect how waves behave when switching mediums?

The behavior of waves when switching mediums is affected by the density, elasticity, and temperature of the medium. A medium with higher density and elasticity will cause waves to travel at a slower speed and bend more when refracted. Temperature also plays a role as it can affect the density and elasticity of the medium.

4. How does the angle of incidence affect the behavior of waves when switching mediums?

The angle of incidence, which is the angle at which the wave meets the new medium, plays a significant role in determining how waves behave. When the angle of incidence is perpendicular to the surface of the new medium, the wave will be transmitted without any change in direction. As the angle of incidence increases, the wave will be reflected more, and less will be transmitted.

5. What are some real-life applications of understanding the properties of waves switching mediums?

Understanding the properties of waves switching mediums is crucial in many fields, including engineering, medicine, and telecommunications. For example, engineers use this knowledge to design structures that can withstand seismic waves during earthquakes. In medicine, ultrasounds use waves that can switch between different mediums to create images of internal body structures. In telecommunications, understanding how waves behave when switching mediums allows for the development of efficient communication systems.

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