I wanted to calculate the frequency of an electron. The problem is that I just don't get a realistic value. E=hf In which: h=4.135 667 33×10 −15 eV s E=mc2+30keV (-> e.g. the energy of a tv) Masselectron=9.10938215×10 −31 kg c=299 792 458 m s-1 So: (9.10938215×10 −31 kg * (299 792 458 m s-1)2) + 30keV= hf 8.1871*10-14J +30 keV=hf 541000 eV=hf (541000 eV)/(h)=f (541000 eV)/(4.135 667 33×10 −15 eV s)=f f=1.308*1020 s-1 Isn't this a non-realistic number? How can they accelerate electrons in an accelerator if the frequency is so big? Or (which is probably more realistic) where am I wrong? Thanks!