In pair annihilation, two gamma-ray photons created, travel in opposite directions not in the same direction, because:
Correct answer: B. This proves law of conservation of momentum
- A. This proves law of conservation of energy
- B. This proves law of conservation of momentum
- C. This proves law of conservation of charge
- D. This proves law of conservation of mass-energy
Explanation
The inverse process to pair production is called pair annihilation, in which a particle and its antiparticle collide and annihilate each other, the total energy of the two particles appearing as electromagnetic radiation.Diagram:
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About Dawn of Modern Physics
Classical physics cannot explain blackbody radiation and related observations, leading to Planck’s quantum theory, in which energy is emitted or absorbed in discrete packets. Photons provide the particle model of light, with energy and momentum linked to frequency and wavelength, including the photoelectric effect and its threshold frequency.
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