Physics Help Forum Energy and momentum related to photon wavelength

 Nuclear and Particle Physics Nuclear and Particle Physics Help Forum

 Jul 26th 2010, 11:29 PM #1 Senior Member   Join Date: Feb 2009 Location: Singapore Posts: 206 Energy and momentum related to photon wavelength An X-ray photon has a wavelength of 3.3*10^-10m. Calculate the momentum mass and energy of the particle associated with the photon, which moves with a velocity c. I used p=h/(lambda) to find the momentum. p=6.6*10^-34/3.3*10^-10=2.0*10^-24 Ns answer is supposed to be 2.2*10^-24Ns Mass=p/c=2.0*10^-24 Ns/3.0*10^8=6.7*10^-33kg answer is supposed to be 6.2*10^-33kg E=mc^2=6.7*10^-33*(3.9*10^8)^2=6*10^-16J which is correct. Can anyone tell me why the first two answers are wrong? Thanks! __________________ To each his own.

 Tags energy, momentum, photon, related, wavelength

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