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### Homework Questions Ch1 #7

Posted: Thu Oct 11, 2018 4:23 pm
chapter 1

#7: can someone please describe to me in detail (i never learned any of this in highschool so i am very lost) how to convert Hz into nanometers? Thank you!!!!!!!

### Re: Homework Questions Ch1 #7

Posted: Thu Oct 11, 2018 4:41 pm
For this question we're given the frequency and told to find the wavelength. In order to do this, we can use the equation:
$\lambda$(wavelength) x $\nu$(frequency) = c(speed of light)

plugging in what we have from part a of the question, this would give us:
$\lambda$(7.1 x 1014)Hz = 3.00 x 108m/s
when we solve for $\lambda$ we get $\lambda$ = 4.2 x 10 -7m and since nanometers are 10-9, 4.2 x 10 -7m is equivalent to 420nm

part b of the question is the same except they ask for the wavelength in picometers (10-12)

### Re: Homework Questions Ch1 #7

Posted: Thu Oct 11, 2018 9:13 pm
Hz is the derived SI unit of frequency and nanometer is a unit of length in the metric system, so we cannot convert between the two. However, Hz can be rewritten as s^-1. By using the formula λ(wavelength) = c(speed of light)/v(frequency), the units will eventually cancel out and leave you with m, which you will need to convert to nm and pm for parts a and b, respectively.