What Is the Maximum Wavelength Photon That Can Produce a Pair

Multiple Choice

What is the maximum wavelength photon that can produce a pair of tau particles (mass $1.777 \mathrm{GeV} / \mathrm{c}^{2}$ ) by pair production?

A) $6.98 \times 10^{-7} \mathrm{~nm}$
B) $1.74 \times 10^{-7} \mathrm{~nm}$
C) $8.72 \times 10^{-8} \mathrm{~nm}$
D) $3.49 \times 10^{-7} \mathrm{~nm}$