Pair production cannot take place in a vacuum as ________________?
Correct answer: C. Momentum is not conserved
- A. Mass is not conserved
- B. Energy is not conserved
- C. Momentum is not conserved
- D. The chargee is not conserved
Explanation
A single photon cannot produce an electron-positron pair in empty space because energy and momentum cannot both be conserved by the products alone. A nearby nucleus is needed to take up recoil momentum, so momentum conservation is the relevant reason, not failure of charge or energy conservation.
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About Photons and the Particle Model of Light
The particle model treats light as photons with energy E equals hf and momentum related to wavelength. Questions involve the photoelectric effect, work function, threshold frequency, stopping potential and photon energy, while distinguishing particle behaviour from the wave description of interference and diffraction.
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