## Sapling Week 2-4 HW Question 24

$\lambda=\frac{h}{p}$

Vivian Leung 1C
Posts: 221
Joined: Wed Sep 30, 2020 10:09 pm

### Sapling Week 2-4 HW Question 24

Hi,

Could someone please help me with this problem? The problem asks for me to classify the wave patterns (see attached image) according to whether or not they are compatible with de Broglie's description of the allowed Bohr orbits of the H atom.
Attachments

Vivian Leung 1C
Posts: 221
Joined: Wed Sep 30, 2020 10:09 pm

### Re: Sapling Week 2-4 HW Question 24

I thought that only the last two waves found on the right column (if you go from the top to bottom) were compatible because those waves are the only ones that are "in-phase". However, I did not get the question right and was just a little confused as to why.

Sophia Spungin 2E
Posts: 94
Joined: Wed Sep 30, 2020 9:41 pm

### Re: Sapling Week 2-4 HW Question 24

I believe that the first and second waves in the right column would work! Basically, if you repeated this same wave segment where the previous wave segment ended, it should create a continuous wave. Because the first and the second waves create a pattern in which the last iteration of the wave could continue directly into the first, these fit the model. If the model begins with a crest, it must end in a trough. The other waves listed in the right column begin and end in the same phase of the wave, or partially through a phase of the wave, so repeating that same segment beginning where the last segment ended would not work.

Vivian Leung 1C
Posts: 221
Joined: Wed Sep 30, 2020 10:09 pm

### Re: Sapling Week 2-4 HW Question 24

Thank you Sophia! That makes sense.

Tiffanny_Carranza_2D
Posts: 64
Joined: Fri Oct 02, 2020 12:15 am

### Re: Sapling Week 2-4 HW Question 24

Sophia Spungin wrote:I believe that the first and second waves in the right column would work! Basically, if you repeated this same wave segment where the previous wave segment ended, it should create a continuous wave. Because the first and the second waves create a pattern in which the last iteration of the wave could continue directly into the first, these fit the model. If the model begins with a crest, it must end in a trough. The other waves listed in the right column begin and end in the same phase of the wave, or partially through a phase of the wave, so repeating that same segment beginning where the last segment ended would not work.

Thank you so much this problem was so confusing, you really helped me visualize it.

anikamenon2H
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### Re: Sapling Week 2-4 HW Question 24

I was confused about this too, especially what "continuous" meant. But I think the easiest way to think about it is that there needs to be a whole number of wavelengths. So the 2nd from the top on your right hand column has 2 full wavelengths and the top one on your right column has 4 full wavelengths. These are the only 2 that have an integer amount of wavelengths. If you have a whole number, then the ends will match up and it will be continuous.

Hope this helps!

Inderpal Singh 2L
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### Re: Sapling Week 2-4 HW Question 24

They have to be "uniform" throughout the whole wave. (same length wavelengths and amplitude). They also have to end where the beginning of the wave begins. Visualize it as putting multiple of these waves together, would they fit together like a puzzle piece? This was very hard to describe in words but I hope this helps :)

Posts: 95
Joined: Wed Sep 30, 2020 9:35 pm

### Re: Sapling Week 2-4 HW Question 24

This thread is so useful! I tried this problem so many times, and you guys helped me understand the correct answer! Thanks, everyone!

Joshua Swift
Posts: 90
Joined: Wed Sep 30, 2020 9:50 pm

### Re: Sapling Week 2-4 HW Question 24

The last two are not compatible because the waves ends do not perfectly match up if you were to model them on an orbit around the atom. If there is a break in the wave, it won't be compatible.

Megan Lu 3D
Posts: 90
Joined: Wed Sep 30, 2020 9:49 pm

### Re: Sapling Week 2-4 HW Question 24

Hi! I think that the bottom two in the right column would not be compatible—in order for the wave patterns to be compatible, they should be continuous and consistent in amplitude and wavelength. I try to imagine copy-pasting the graphs side by side to see if it would create a function resembling a sine function. If there are any discrepancies (change in pattern, discontinuities, etc.) in it, then it would not be compatible.

Posts: 50
Joined: Wed Sep 30, 2020 10:01 pm

### Re: Sapling Week 2-4 HW Question 24

The ones that will be correct should essentially be a never ending series. So if you get to the end and you can immediately start where the beginning of the wave starts then you will be good.

Jose Miguel Conste 3H
Posts: 91
Joined: Sat Oct 03, 2020 12:15 am

### Re: Sapling Week 2-4 HW Question 24

when the wavelength is continuous from when you add the picture again to both sides, it is compatible, but if the wavelength is not continuous when you add the photo of the wave from either side, then it is not compatible