Passage III

All known exoplanets (planets in orbit about stars other than the Sun) are too distant from Earth to be studied in detail, so mathematical models have been developed to help predict their properties. Figures 1-3 each show how a different property varies with altitude above the surface of Earth and above the surfaces of 2 hypothetical exoplanets: Planet X and Planet Y. Figure 1 shows how atmospheric temperature, T (in kelvins, K), varies; Figure 2 shows how atmospheric pressure, how P (in atmospheres, atm), varies; and Figure 3 shows how gravitational field strength, g (in newtons per kilogram, N/kg), varies.

17. Atmospheric density and P are directly proportional to each other. Based on Figure 2, which planet more likely has the more dense atmosphere at an altitude of 5 km, Earth or Planet Y ?

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

Looking at Figure 2, when the abscissa is 5, the ordinate of Earth is about 0.5, and the ordinate of Planet Y is about 0.15, so the air pressure here on Earth is greater than that on Planet. According to the information given in the stem of the question "atmospheric density is proportional to air pressure", it can be known that the atmosphere here on Earth is denser.