The passage of `gamma` -rays photons through materials sometimes results in pair production, i.e., the transformation of a `gamma` -rays photon into a positron and an electron (eachof mass m). What is the maximum wavelength of `gamma - `ray photons for which pair production is possible?
(c = speed of light, h = plank constant)

Options

A. `(1)/(2 "mch")`
B. `(1)/(2 mc^(2)h)`
C. `(h)/(2 mc)`
D. `(h)/(2 mc ^(2))`

Answer

C