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Old 20-03-2014, 12:41 PM
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sjastro
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Since energy and momentum are conserved, the "classical" equations for energy and momentum are interchangeable. (In relativity energy and momentum are linked into a single identity).

Instead of using the equation E=hv, one can use the photon momentum equation p=hv/c. In this case part of the momentum of the photon is transferred to the particle for inelastic collisions.

Also hard UV photons can indirectly impart momentum changes on matter. For example a photon can ionize or strip electrons from an atom. The resulting electrons carry momentum which is further increased by scattering photons. These electrons collide into matter imparting momentum.

Regards

Steven
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