What is the energy threshold for pair production to occur?

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Multiple Choice

What is the energy threshold for pair production to occur?

Explanation:
Pair production needs enough energy to create both an electron and a positron. Each has a rest mass energy of 0.511 MeV, so two of them require 1.022 MeV in total. A nearby nucleus (or another charged particle) is involved to conserve momentum during the process. Any extra energy above 1.022 MeV becomes kinetic energy of the pair or recoil. So the energy threshold is 1.022 MeV. If the photon energy is below this, pair production can’t occur; at or above this value, it can begin.

Pair production needs enough energy to create both an electron and a positron. Each has a rest mass energy of 0.511 MeV, so two of them require 1.022 MeV in total. A nearby nucleus (or another charged particle) is involved to conserve momentum during the process. Any extra energy above 1.022 MeV becomes kinetic energy of the pair or recoil. So the energy threshold is 1.022 MeV. If the photon energy is below this, pair production can’t occur; at or above this value, it can begin.

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