Question

At the top of a mountain a thermometer reads $7^{\circ }C$ and a barometer reads 70 cm of Hg. At the bottom of the mountain these read ${27}^{\circ }C$ and 76 cm of Hg respectively. Comparison of density of air at the top with that of bottom is

• A. 75/76
• B. 70/76
• C. 76/75
• D. 76/70

Answer 1

The correct option is A

75/76

$\frac{P_1}{T_1{\rho }_1}=\frac{P_2}{T_2{\rho }_2}$

$\frac{{\rho }_1}{{\rho }_2}=\frac{70.300}{76.280}=\frac{75}{76}$