The temperature, at which the root mean square velocity of hydrogen molecules equals their escape velocity from the earth, is closest to
[Boltzmann constant $\mathrm{k}_{\mathrm{B}}=1.38 \times 10^{-23} \mathrm{~J} / \mathrm{K}$
Avogadro Number $\mathrm{N}_{\mathrm{A}}=6.02 \times 10^{26} / \mathrm{kg}$
Radius of Earth : $6.4 \times 10^6 \mathrm{~m}$
Gravitational acceleration on Earth $=10 \mathrm{~ms}^{-2}$ ]