Let "m" represent the mass of an electron, and "c" represent the speed of light. In order to create an electron-positron pair, we must start with a photon whose energy is

A) at least mc2.
B) at least 2mc2.
C) at least 4mc2.
D) any value greater than zero.
E) Actually it is impossible to create such pairs from photons.


B

Physics & Space Science

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