A = log (I_{o}/I)

antilog 0.680 = 1 x 10^{18 }photons / I

I = 2.09 x 10^{17} photons

Therefore the number of photons transmitted is 2.09 x 10^{17}.

What is the wavelength of the transmitted photons?

1) longer than the initial beam.

2) the same as the initial beam.

3) shorter than the initial beam.