Chemistry
posted by Trina .
The equation for photon energy, , is
where = 6.626×10−34 (Planck's constant) and = 3.00×108 (the speed of light).
What is the wavelength, , of a photon that has an energy of = 3.99×10−19 ?
How do go about solving this? I multipled the constant w/ the speed of light and divided it by the proton energy but its not correct

You omitted the important stuff in your definition workup.
w = wavelength
c = speed of light = 3E8 m/s
h = Planck's constant = 6.626E34 J.s
E = energy in J.
E = hc/w
3.99E19 = 6.626E34*3E8/w
w = 6.626E34*3E8/3.99E19 = ?
If you still have a problem, put your exact work in a post and let us take a look at it. One problem students often make is using too many significant figures in the answer. Check that too. 
A photon has a wavelength of 6.2 meters. Calculate the energy of the photon in joules. (Planck's constant is 6.626 × 1034 joule seconds, the speed of light is
2.998 × 108 m/s)? I'm confused in how to find the answeer.