When making calculations w/ wavelength, what unit to use? [ENDORSED]

[NaomiAbramowicz1H]

Hi! When making calculations using wavelength (lambda), should I use nm or m? Is it different depending on the situation?

[Ashley Tonthat 2B]

Hi Naomi,

I think it's reported in meters since it is an SI unit. Hope that helps.

[Xuan Lai 1H]

Meters are the standard SI unit, so it would be best to use that, unless the question specifies otherwise!

[Grant_2A]

Hi,

The meter tends to be the default measurement in scenarios like these because it is the standard SI unit!

[Albert Chen 1G]

It is best to use the measurement of m (meters) not only because it is the standard unit, but because constants like the speed of light are in meters/second. This helps with solving calculations and saves you one step in the process.

[masontsang]

Hi! I would use meters since meters are the SI unit. Using meters makes it convenient if you have to do any conversions or stoichiometry. If you need to convert to nm, at the end of the problem you can always multiply your answer by a factor of 10^9! I hope this helps!

[Furkan Acar 3C]

I'm assuming we use meters, simply because it's an SI Unit. Could totally be wrong though, would look into it further.

[Elizabeth Kim 2K]

Hi! When making calculations with wavelength, I would use meters (m) since that is the SI base unit (unless the question specifies to convert your answer to nm or another unit). Hope this helps!

[Chem_Mod]

Hello Naomi,

Just to clarify, calculations with wavelength (i.e. ) should always include the appropriate units in order to cancel out factors as a general trend.

For instance, if you were to relate the equation about to solve for an unknown with (m/s) and (nm for example), you would need to convert from nanometers into meters first prior to solving the calculation for frequency.

[Srikar_Chintala_1E]

I would use meter because that is the standard SI unit for length. It is also really easy to use meters when dealing with speed of light and frequency. I would only really use nanometers if the question asks you to convert it to those units.