Wavelength


Moderators: Chem_Mod, Chem_Admin

Constance Newell
Posts: 89
Joined: Wed Sep 30, 2020 9:38 pm

Wavelength

Postby Constance Newell » Tue Oct 27, 2020 10:21 am

Is wavelength always converted into m or are there any instance where wavelength must be in nm?

DanielHong2L
Posts: 55
Joined: Wed Sep 30, 2020 9:51 pm

Re: Wavelength

Postby DanielHong2L » Tue Oct 27, 2020 10:44 am

Constance Newell wrote:Is wavelength always converted into m or are there any instance where wavelength must be in nm?


If the final answer is in nm then it should be in nanometers. The primary reason we convert it to m is to use formulas with constants which are oftentimes given in terms of m, kg, s... etc. Otherwise you'd have to convert the constants/other aspects of the formulas in terms of nm.

Constance Newell
Posts: 89
Joined: Wed Sep 30, 2020 9:38 pm

Re: Wavelength

Postby Constance Newell » Tue Oct 27, 2020 10:46 am

Okay, thanks!
Is there a specific reason why we use kg for De Broglie's equation?

Alexa Pham 1D
Posts: 69
Joined: Wed Sep 30, 2020 10:03 pm

Re: Wavelength

Postby Alexa Pham 1D » Tue Oct 27, 2020 4:35 pm

kg is an SI unit. Also, in de Broglie's equation, Planck's constant (in the numerator) has the units Js. Remember that J is equal to kg m^2 s^-2. We need to cancel the kg out with a kg in the denominator so that we can eventually get the unit m for wavelength.

Moura Girgis 1F
Posts: 96
Joined: Wed Sep 30, 2020 10:00 pm

Re: Wavelength

Postby Moura Girgis 1F » Fri Oct 30, 2020 5:53 pm

When solving a problem, wavelength must always be written in terms of m, since the other variables in the equation would be in m. However, when writing the wavelength as the final answer, it should be converted to nm in order to determine the spectrum.

Natallie K 3B
Posts: 61
Joined: Wed Sep 30, 2020 9:51 pm

Re: Wavelength

Postby Natallie K 3B » Fri Oct 30, 2020 6:10 pm

Wavelength must be written in m because it is the SI unit for length. However, sometimes the answer may ask you to convert the answer from meters to nanometers, so the value is not so small

Colin Squire 3B
Posts: 90
Joined: Wed Sep 30, 2020 9:35 pm

Re: Wavelength

Postby Colin Squire 3B » Fri Oct 30, 2020 7:02 pm

Since the SI unit for distance is meters, nanometers would need to be converted. This would just make it easier to compute using the de Broglie relation because the speed of light units is in meters per second.

Juliana Rosales 1H
Posts: 105
Joined: Wed Sep 30, 2020 9:43 pm

Re: Wavelength

Postby Juliana Rosales 1H » Sun Nov 01, 2020 11:08 pm

It would depend on what the question is asking, but other than that do what’s easiest for you

George Hernandez 3I
Posts: 90
Joined: Wed Sep 30, 2020 9:52 pm

Re: Wavelength

Postby George Hernandez 3I » Sun Nov 01, 2020 11:16 pm

All wavelength equations would require you to convert to meters since that is an S.I. unit.

Madeline Ogden 3B
Posts: 107
Joined: Wed Sep 30, 2020 10:03 pm
Been upvoted: 1 time

Re: Wavelength

Postby Madeline Ogden 3B » Tue Nov 03, 2020 2:47 pm

When doing calculations, wavelength should always be converted to meters in order to ensure that the correct SI unit is being used. However, when giving an answer dealing with wavelength, it's best to give the answer in nm as this is normally the length that they are given in. From what I know, radio wavelengths are the only ones that are sometimes given in nm rather than m because of how long then are. Hope this helps!

Jack_Pearce_2H
Posts: 99
Joined: Wed Sep 30, 2020 9:48 pm

Re: Wavelength

Postby Jack_Pearce_2H » Wed Nov 04, 2020 3:26 pm

it depends on the question, but its a pretty easy conversion (1m=1x10^9nm) so i wouldnt fret too much about converting, just pay attention to the problem at hand :)

Taber Ball 1F
Posts: 50
Joined: Wed Sep 30, 2020 9:51 pm

Re: Wavelength

Postby Taber Ball 1F » Thu Nov 05, 2020 10:47 am

Hi! Does anyone have a good way to memorize the various wavelengths on the atomic spectrum?

Eunice_Castro_1G
Posts: 91
Joined: Wed Sep 30, 2020 9:46 pm

Re: Wavelength

Postby Eunice_Castro_1G » Thu Nov 05, 2020 10:56 am

Wavelength should be written in meters, since it that is the correct si units. It just happens that sometimes we get an answer like with x10^-9 meters, and that is the same thing as nanometers. So, it may just be easier to refer to our answer in nanometers. And visible light is mainly all x10^-9 so we often refer to it in nanometers. Hope this helps!

Hannah Rim 2D
Posts: 58
Joined: Wed Sep 30, 2020 9:48 pm
Been upvoted: 1 time

Re: Wavelength

Postby Hannah Rim 2D » Thu Nov 05, 2020 4:27 pm

Wavelength is usually converted to m as the default. However, if the problem is asking for a different unit of measure then we would have to convert our answer.

Lung Sheng Liang 3J
Posts: 90
Joined: Wed Sep 30, 2020 9:33 pm

Re: Wavelength

Postby Lung Sheng Liang 3J » Fri Nov 06, 2020 3:40 pm

The standard unit for wavelength is generally meters. However, we should convert to nm if the question asks.

Heidi Buri 2I
Posts: 50
Joined: Wed Sep 30, 2020 9:57 pm

Re: Wavelength

Postby Heidi Buri 2I » Sat Dec 12, 2020 12:07 pm

Hi! When doing the calculations, wavelength will be in m. This is because the values of all the constants are in terms of meters. After finding the value of the wavelength in meters, it can be converted to nm. I would assume that the wavelength is in meters, but if the problem asks for the wavelength to be in nm, I would convert meters to nano meters (1nm=1x10^-9 m).

Jaden Ji 2K
Posts: 50
Joined: Wed Sep 30, 2020 9:54 pm

Re: Wavelength

Postby Jaden Ji 2K » Sat Dec 12, 2020 12:10 pm

Taber Ball 1F wrote:Hi! Does anyone have a good way to memorize the various wavelengths on the atomic spectrum?

I like to relate the terms to the things that remind me of the term, like nanometer is like nine-o-meter, because it is 10^-9 m. Hope this helps!

Kimiya Aframian IB
Posts: 126
Joined: Wed Sep 30, 2020 9:34 pm

Re: Wavelength

Postby Kimiya Aframian IB » Sat Dec 12, 2020 12:11 pm

Constance Newell wrote:Is wavelength always converted into m or are there any instance where wavelength must be in nm?

When doing calculations, it usually needs to be in the SI unit of m. It may ask for a conversion in the end of the problem though. Hope this helps!

Sreeram Kurada 3H
Posts: 93
Joined: Wed Sep 30, 2020 10:00 pm

Re: Wavelength

Postby Sreeram Kurada 3H » Sat Dec 12, 2020 12:21 pm

A general rule of thumb is to use m instead of nm for solving for photoelectric effect problems or de brogile problems. However, when you are solving for atomic spectra type of problems, you should be using nm.

simona_krasnegor_1C
Posts: 50
Joined: Wed Sep 30, 2020 9:35 pm

Re: Wavelength

Postby simona_krasnegor_1C » Sat Dec 12, 2020 6:58 pm

Usually what I do is see what the equation I'm using is, because I want the units to be able to cancel; this usually helps me make my decision!

Moura Girgis 1F
Posts: 96
Joined: Wed Sep 30, 2020 10:00 pm

Re: Wavelength

Postby Moura Girgis 1F » Tue Dec 15, 2020 5:52 pm

wavelength should always be m unless the question is asking for a different unit.

Brandon Carris
Posts: 49
Joined: Wed Sep 30, 2020 9:41 pm

Re: Wavelength

Postby Brandon Carris » Tue Dec 15, 2020 5:58 pm

Wavelength should be in meter because all equations usually take measures of length in meters

Morgan Gee 3B
Posts: 95
Joined: Wed Sep 30, 2020 9:48 pm

Re: Wavelength

Postby Morgan Gee 3B » Wed Dec 16, 2020 7:28 am

Wavelength is typically converted to meters for calculations because the meter is the base unit for length. This results in most other units (such as Joules) using meters.

805593945
Posts: 43
Joined: Wed Sep 30, 2020 9:36 pm

Re: Wavelength

Postby 805593945 » Wed Dec 16, 2020 8:33 am

Most of the equations with wavelength use meters.

Hailey Qasawadish 2J
Posts: 71
Joined: Wed Sep 30, 2020 9:36 pm
Been upvoted: 1 time

Re: Wavelength

Postby Hailey Qasawadish 2J » Wed Dec 16, 2020 9:47 am

You always want to base your answer off of what the question is asking for, but in order to do calculations, most have to be done with the units in meters.

CesarLec1
Posts: 67
Joined: Wed Sep 30, 2020 9:49 pm

Re: Wavelength

Postby CesarLec1 » Thu Dec 17, 2020 1:10 am

It depends on what the question is asking for, sometimes it asks for nm but most of the time it asks for it in meters. However, if you were to use it in other calculations, make sure it is always in meters.

Adam_ElSayed_3B
Posts: 51
Joined: Wed Sep 30, 2020 9:48 pm

Re: Wavelength

Postby Adam_ElSayed_3B » Thu Dec 17, 2020 2:37 am

Determining spectrum would be a good example of nm, but I'm sure in experimentation it isn't hard to switch between the two at all.


Return to “Properties of Light”

Who is online

Users browsing this forum: No registered users and 1 guest