The temperature, at which the root mean square
velocity of hydrogen molecules equals their
escape velocity from the earth, is closest to :
[Boltzmann Constant kB = 1.38 × 10–23 J/K
Avogadro Number NA = 6.02 × 1026 /kg
Radius of Earth : 6.4 × 106 m
Gravitational acceleration on Earth = 10ms–2]