## Wavelength Plausibility

H-Atom ($E_{n}=-\frac{hR}{n^{2}}$)

ahuang
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### Wavelength Plausibility

In the lecture slides, it said that an electron's wavelength is around 10^-12m. In the modules it asks if certain wavelengths are able to be detected. I just wanted to confirm that if the wavelength smaller than 10^-12, it is detectable. But how much smaller is detectable? Is ~10^-15m acceptable?

Chem_Mod
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### Re: Wavelength Plausibility

The context here is when does a particle cease to have detectable wave-like properties. In other words only particle-like behavior will be observed.
Typically a particle with a de Broglie wavelength less than 10-15m does not have detectable wave-like properties. Obviously the higher the mass, the smaller the wavelength and therefore more likely to have only particle-like behavior.

In class I will discuss this and show, using calculated values, that a baseball has only particle-like behavior (as its de Broglie wavelength is far too small to have any detectable wave-like properties).

Natalie Benitez 1E
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### Re: Wavelength Plausibility

I remember in the lecture the slides said that visible light can be seen from 700nm (Red) to 400nm (Violet) but in the picture from the slides it went up to 720 nm. So, basically my question is if visible light ranging from 700 nm to 400nm or from 720nm to 400nm.

Angela Patel 2J
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### Re: Wavelength Plausibility

He said that it is 720 to 400 but that we can just remember 700 to 400 since it's easier!

KatherineValdez_4B
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### Re: Wavelength Plausibility

So if we remember 700 rather than 720 are we still correct?

Amy Pham 1D
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### Re: Wavelength Plausibility

The upper limit of the correct range was, as the slides depicted, 720 nm. This is the correct number, 700 is just a simple round number to have a mental ballpark estimate.

nicole-2B
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### Re: Wavelength Plausibility

APatel_4A wrote:He said that it is 720 to 400 but that we can just remember 700 to 400 since it's easier!

Thank you for clarifying .

AveryAgosto
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### Re: Wavelength Plausibility

Anything smaller than 10^-15 is not detectable.

Robert Cross 1A
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### Re: Wavelength Plausibility

Thank you for the clarification!

Abigail_Hagen2G
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### Re: Wavelength Plausibility

Okay, so all we have to remember is that the range of visible light is from around 700 nm to 400 nm, and that anything below 10^-15 is not detectable?

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### Re: Wavelength Plausibility

Yes, the 700-400nm example he gave is meant to provide a mental picture of the range however the actual scale is from 720-400. Either way you want to remember it is ok.

Alan Cornejo 1a
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### Re: Wavelength Plausibility

madeleine_dis1E wrote:Yes, the 700-400nm example he gave is meant to provide a mental picture of the range however the actual scale is from 720-400. Either way you want to remember it is ok.

correct, 700 is just used for an easier conceptualization of the actual range

Ruth Glauber 1C
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### Re: Wavelength Plausibility

I believe using 700 to 400 is acceptable (and easier to remember).

005162520
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### Re: Wavelength Plausibility

Quick clarification, why isn't not detectable?

Nathan Rothschild_2D
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### Re: Wavelength Plausibility

The problems we have been doing have been involving visible light. 10^-15 would fall in the ultraviolet spectrum and would not be detectable to the human eye.

Katherine Brenner 3H
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Joined: Wed Sep 18, 2019 12:18 am

### Re: Wavelength Plausibility

Does that mean that the larger an electrons wavelength is, the more wave-like properties it possesses?

Angela Prince 1J
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### Re: Wavelength Plausibility

APatel_4A wrote:He said that it is 720 to 400 but that we can just remember 700 to 400 since it's easier!

Because it differs so much according to different tables, I think it will be fine if you just remember 700 to 400

melinak1
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Joined: Tue Sep 24, 2019 12:17 am

### Re: Wavelength Plausibility

Angela Prince 3B wrote:
APatel_4A wrote:He said that it is 720 to 400 but that we can just remember 700 to 400 since it's easier!

Because it differs so much according to different tables, I think it will be fine if you just remember 700 to 400

thank you!!

brennayoung
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### Re: Wavelength Plausibility

I know he said 720 to 400 but 700 was acceptable but wouldn't that change the calculations?

AnayaArnold_3L
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### Re: Wavelength Plausibility

Thank you so much!

RBergtraun_3A
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### Re: Wavelength Plausibility

I had a similar question, this video helped me a lot. Hope it helps you. https://www.khanacademy.org/science/phy ... c-spectrum

Natalie Benitez 1E
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### Re: Wavelength Plausibility

APatel_4A wrote:He said that it is 720 to 400 but that we can just remember 700 to 400 since it's easier!

Thank you !!!

905289082
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### Re: Wavelength Plausibility

Technically, if the question asks if the wavelength is detectable, or more often it will ask if there are "detectable wavelike properties" that means that it wants to know whether the wavelength is greater than 10e-15 or not.

Ruth Glauber 1C
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### Re: Wavelength Plausibility

I think that a de Broglie wavelength less than 10-15m does not have detectable wave-like properties.

KatherineValdez_4B
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### Re: Wavelength Plausibility

What is the final unit for the wavelength?

Jaklin Astvatsatryan
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### Re: Wavelength Plausibility

KatherineValdez_4B wrote:What is the final unit for the wavelength?

A unit of wavelength is in meters which you can convert to nm.

AnayaArnold_3L
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### Re: Wavelength Plausibility

Thanks!!!!
RBergtraun_3A wrote:I had a similar question, this video helped me a lot. Hope it helps you. https://www.khanacademy.org/science/phy ... c-spectrum

CNourian2H
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### Re: Wavelength Plausibility

905289082 wrote:Technically, if the question asks if the wavelength is detectable, or more often it will ask if there are "detectable wavelike properties" that means that it wants to know whether the wavelength is greater than 10e-15 or not.

That makes a lot of sense! A good thing to look out for, thanks!

bloodorangefield
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### Re: Wavelength Plausibility

Wouldn't the difference from 720 to 700 make a significant enough difference?

Hussain Chharawalla 1G
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### Re: Wavelength Plausibility

It would, but I think for the purposes of the class we only need to remember 700-400 nm.

brennayoung
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### Re: Wavelength Plausibility

For the final do we need to have the different wavelength series memorized for the energy required to raise it one energy level like quantum state =1, n=2 etc?