Chemistry
posted by Anon .
Suppose that absorbances of several solutions were measured at 545 nm. What is the frequency of this wavelength? What is the energy of this wavelength? (h=6.626 times 10^34J*S)

c = freq x wavelength.
c = 3E8 m/s
freq = ? in Hz.
wavelength = 545 nm x 10^9 m
For E in J = hc/wavelength. 
What is the freq? You got C=2x10^8m/s but you don't have the freq.

What did you use for the freq?

Isn't the problem asking for frequency? You use c = f*w to solve for f.
And I don't see anywhere that I have 2E8 m/s.
c = f*w
3E8 = f*545E9
Solve for f. 
Is F=5.55*10^14Hz?

close. I obtained 5.504E14 Hz which I would round to 5.50E14 Hz to three significant figures..

For the energy is it around 3.647x10^19J? And how did you know that c=3*10^8m/s?

c is the speed of light. Look in your text for a table of physical constants and you will find the speed of light as 299,792,458 m/s which most of us round to 3E8 m/s most of the time.
I found E to be the same number you have.