## Error in Lec #6?

Joseph Hsing 2C
Posts: 99
Joined: Wed Sep 30, 2020 9:42 pm

### Error in Lec #6?

I could be wrong but when the prof was calculating the wavelengths if the first example wouldn't the answer be 551 x 10^-7 instead of 551 x 10^-9?

Farah Abumeri 3F
Posts: 105
Joined: Wed Sep 30, 2020 9:51 pm
Been upvoted: 2 times

### Re: Error in Lec #6?

If you were writing the wavelength as 5.51 then it would be 5.51x10^-7 m. Professor Lavelle wrote the wavelength as 551 with no decimal, so it would be 551x10^-9 m. I think that because we are using scientific notation the correct answer would be 5.51x10^-7 m. But 5.51x10^-7 m and 551x10^-9 m are technically the same value!

Aaron Akhavan-Dis1B
Posts: 106
Joined: Wed Sep 30, 2020 9:59 pm

### Re: Error in Lec #6?

Nm is equal to 10^-9 m. The question will specify whether to use m, nm, or whatever unit as an answer. He did start off with 5.51 x 10^-7 m, but in order to make it a nm you have to move the decimal two places to the right since you are making the -7 into a -9. Hope this helps.

Joseph Hsing 2C
Posts: 99
Joined: Wed Sep 30, 2020 9:42 pm

### Re: Error in Lec #6?

Ah I see I wasn't paying attention to the decimal. Thank you!