relationships between frequency, wavelength, and velocity

[Sami Ryan 1G]

Something I think is good to know:

frequency and wavelength are inversely proportional, because C = wavelength * frequency

But velocity and wavelength are proportional, because V = frequency * wavelength

Velocity probably needs to be converted into m/s

Is wavelength written in m or nm? Or should it be m in the equation but nm as a final answer?

(besides this sentence, this is unedited to preserve the thread, but this isn't right, debroglie equation actually gives an accurate relationship between velocity and wavelength)

[Ruben Adamov 1E]

Usually when solving a problem the units will require a conversion into m. But the final answer should whatever the question asks for. If it doesn't ask for anything you can write the answer in any unit you want as long as you specify if it is m, nm, pm, etc.
Hope this helps!

[Alex Luong 3H]

I think it would depend on what the question is asking. Usually, you would use meters, since that is the SI unit for length, but I guess you could always convert meters to nanometers if the question wants nm.

Also, are you sure you have the right equation for the relationship between velocity and wavelength? I'm looking at the formula sheet and there's an equation E= hv = energy = frequency times planck's constant. I thought that de Broglie's equation is the only 1 that relates wavelength and the particle's velocity. For that equation, if velocity is a big value, then p (momentum) would be greater, which would lead to a shorter wavelength, so velocity and wavelength are inversely proportional. At least, that's my take.

[Sami Ryan 1G]

Alex, you're totally right. I really just put the same equation down twice. Doesn't that mean C is the velocity though? It is in m/s. I don't think I understand it conceptually, how C isn't the velocity even though it is the wavelength * frequency.

Debroglie is definitely the thing to use here. Wavelength = plancks constant / (mass * velocity)
This means that they would be inversely proportional.

Thanks for correcting me

[Isela Tamayo 3H]

the wavelength should always be in meters when you are using it in an equation but if the answer asks for it in nm for example then you should convert.

[JasmineReyes-2K]

Typically the units are specifically asked for in the question so go based off that!

[Crystal Ros 2L]

For plugging into formulas, we will always be using meters for the values, so if any other unit is given, you will need to convert the value to match. This concept also applies to kilograms, Hertz, m/sec, etc.

[Jieun 2C]

When plugging into the equation, make sure that wavelength is in meters. However, for the final answer, check what units the question is asking and you can convert from meters to the units the question is asking.

[Aparna Pillai 1E]

The units of wavelength usually need to be in meters when being plugged into an equation in order to align and/or cancel out with the other numbers and constants in your calculation. As a final answer, wavelength can kept in meters unless the problem specifically asks for it in other units (for instance, nm).

[Jessica Arcos 2H]

When using an equation you should always be using SI units. So if the problem gives you a wavelength of nm then you would have to convert it to m. It depends on each problem what the final units would be but if it asks the wavelength to be in nm then you would convert it back to nm.

[Diego Salgues 2K]

The De Broglie equation takes into account mass of a particle

[Diego Salgues 2K]

The De Broglie equation takes into account mass of a particle