"Colbalt-60 is a radioactive isotope used to treat cancers of the brain and other tissues. A gamma ray emitted by an atom of this isotope has an energy of 1.33 MeV (million electron volts; 1 eV = 1.602*10^-19 J). What is the frequency (in Hz) and wavelength (in m) of this gamma ray?"

I just want to make sure I got the frequency right.

3 answers

Why didn't you post your work? That way we could tell you if you worked it right or not AND you would spend your time typing instead of us.
E =h*c/wavelength. Find wavelength.
c = freq * wavelength. Solve for freqency.
Oh right, sorry about that.

I used E=hf (f=E/h).

So I got E as 2.13*10^-13 J by...(1.33*10^6)(1.602*10^-19).

Using the formula, I got frequency as 3.22*10^20.

I think I've taken a different approach as what you have suggested.
Your method is a little shorter than mine. I arrive at the same answer for frequency. I assume you know the problem also asked for wavelength and that is
c = frequency x wavelength for which I obtained 9+ x 10^-13 meters. Thanks for showing your work.