1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Photon Smashing into Particle

  1. Apr 23, 2010 #1
    An energetic photon strikes a helium nucleus and breaks into two hydrogen isotopes (A = 2, Z = 1). The two particles move off at 0.6c. Assume all energy of the photon is absorbed and that relativistic energies are involved.

    Q - what is the wavelength of the incoming photon?

    Conservation of energy - Ei = Ef
    E(photon) + E(helium) = 2E(hydrogen)

    E(photon) = 2E(hydrogen) - E(helium)

    hc/[tex]\lambda[/tex] = 2([tex]\gamma[/tex]m(H)c^2) - ([tex]\gamma[/tex]m(He)c^2)

    [tex]\gamma[/tex] = 1/sqrt(1-u^2/c^2)

    Then I would solve for [tex]\lambda[/tex] by rearranging the equation.
    Is this how i should be solving this type of problem?

    Thanks
    DoubleMint
     
  2. jcsd
  3. Apr 23, 2010 #2

    collinsmark

    User Avatar
    Homework Helper
    Gold Member

    Hello DoubleMint,

    Was the Helium nucleus (which exists before the collision) initially at rest? You have a [tex] \gamma [/tex] in the helium associated term. And even if it wasn't at rest, it wouldn't have the same [tex] \gamma [/tex] as the one associated with the hydrogen nuclei, would it?
     
  4. Apr 23, 2010 #3
    Hi collinsmark,

    The helium nucleus is initially at rest, so would it be just be the rest energy of the particle, E = mc^2?
    If it was not at rest, [tex]\gamma[/tex] would not be the same. Sorry about that!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Photon Smashing into Particle
Loading...