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.

18. At the surface of a planet, g is given by the equation

where G is a constant, M is the planet's mass, and R is the planet's radius. Assume that Earth, Planet X. and Planet Y have equal radii. Based on Figure 3, which planet has the greatest mass?

Answer and Explanation

Your Answer is

Correct Answer is F

Explanation

According to the information given in the question stem, the radius of the three planets is the same, and the size of g is proportional to M. Looking at Figure 3, when the abscissa is 0 (the surface of a planet and the altitude is 0), the ordinate g of Earth is the largest, which means that the quality of Earth is also the largest.