How many photons are produced in a laser pulse of 0.558 J at 603 nm?

Question

aaronq · Answer

603 nm is the wavelength $(\lambda)$, you need to express this in meters.

$E_{photon}=h\nu=\dfrac{h*c}{\lambda}$

find the energy of one photon of this wavelength, divide the total energy (0.558 J) by the energy of 1 photon $(E_{photon})$. 
c= speed of light, btw.

anonymous · Answer

Okay so I got  E=3.294x10^-19 then I divided it by .588 but its still telling me its wrong.

aaronq · Answer

you divided it the wrong way, divide the total energy by the E of one photon: # of photons=0.588/3.294x10^-19

anonymous · Answer

I'm still managing to get it wrong somehow.

aaronq · Answer

i got 1698151602098946347.99 photons

aaronq · Answer

1.7*10^18

anonymous · Answer

Thats what I put in. I finally just asked to see the solution and it gave me 1.69x10^18 -.- But thanks for the help lol

aaronq · Answer

lol damn, sorry. I guess we didn't follow sig figs.