The height at which the atmosphere ceases to exist is about \(80 km\), if the atmospheric pressure on the ground level is \(760 mmHg\), the pressure at height of \(20 km\) above the ground is ____________
A. \(380 mmHg\) B. \(570 mmHg\) C. \(190 mmHg\) D. \(480 mmHg\)
Correct Answer: C
Explanation
Given: \(H_{1}=80 km , P_{\text {atm }}=760 mmHg\), \(H _{2}=20 km , P _{2}=? P =\rho Hg\) \(P \alpha H\) i.e. \(\frac{P_{1}}{H_{1}}=\frac{P_{2}}{H_{2}} ; P_{2}=\frac{P_{1} \times H_{2}}{H_{1}}\) \(=\frac{760 \times 20}{80}=190 mmHg\)
