## Wavelength Units

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

Connie2I
Posts: 29
Joined: Fri Sep 29, 2017 7:07 am

### Wavelength Units

I was confused about whether wavelength had to be in nanometers or simply meters, because in the module, the answer to 39. was 486 nm, so I answered the next question number 40. with 746 nm, which was wrong. I'm assuming the correct answer was 7.46 x 10^-6 m, but I wasn't sure how to differentiate when the wavelength's answer should be in nm or m.

Gurshaan Nagra 2F
Posts: 49
Joined: Thu Jul 27, 2017 3:01 am

### Re: Wavelength Units

It can be either, sometimes they just convert it to nm when it converts nicely otherwise they tend to leave it in meters.

Shannon Wasley 2J
Posts: 71
Joined: Fri Sep 29, 2017 7:06 am
Been upvoted: 1 time

### Re: Wavelength Units

For most problems it is preferred that the value of the wavelength is in nanometers because it is then easier to see where along the electromagnetic spectrum the wavelength falls. Also, it could be useful to have the value in nanometers for when the next part of the questions asks for what type of region it pertains to. For this problem specifically, it would be easier to leave the value in meters because it would not round neatly in nanometers. A way to tell would be if your number that you calculate for your wavelength has 6 zeros before the three numbers (ex: .000000746), then put it in nanometers. If it has any other amount of zeros in front of the three numbers then keep it in meters.

Kimberly Santander3L
Posts: 16
Joined: Fri Sep 25, 2015 3:00 am
Been upvoted: 1 time

### Re: Wavelength Units

The problem itself will usually tell you whether it wants the final answer in nanometers or in meters. Make sure to double check it before coming up with the final answer.

Alex Leve 3F
Posts: 20
Joined: Fri Sep 29, 2017 7:07 am

### Re: Wavelength Units

Although the final answer may ask for nanometers, when plugging in wavelength to solve for another value, you would always use the meters, as it is the SI unit.

Jessica Nunez 1I
Posts: 58
Joined: Thu Jul 13, 2017 3:00 am

### Re: Wavelength Units

If the problem asks for the wavelength in nanometers, I would provide it in nanometers. However, when you are solving the problem, I would use meters since the SI unit is meters and the values of the other constants are given in meters. Hope this helps!