The height at which the atmosphere ceases to exist is about 80km. If the atmospheric pressure on the ground level is 760mmHg, the pressure at a height of 20km above the ground level is
(ρm = 13.6g/cm\(^3\) ρ = 0.00013g/cm\(^3\) )

A.

380mmHg

B.

570mmHg

C.

190mmHg

D.

480mmHg

Correct answer is B

ρ\(_m\)h\(_m\) = ρ\(_a\)h\(_a\)
13.6(760 - p) × 10\(^{-3}\) = 13 × 10\(^{-5}\)(20 × 10\(^3\))