I'm working on homework and the computer won't accept my answer.

Calculate the energy of photons with wavelenth 0.174 nm.

I used the equation E=hv and got the answer to be 1.14 X 10^-17. It says i'm off by a multiple of ten. I have no idea where I messed up.

2 answers

Are you using frequency instead of wavelength?
E = hc/wavelength
h = 6.626 x 10^-34 J*sec
c = 3 x 10^8 m/s
wavelength = 0.174 x 10^-9 meters.
I find 1.14 x 10^-15 joules so I think you are off by 100.
(a) Calculate the energy of photons of wavelength 3.1 µm.