Appalachians. This same trend holds true for the other percentages as well. Only (A)
accurately describes this trend.
4 . H The passage states that Figure 1 shows the volume of the ash clouds released by volcanoes
of differing diameters. It also states that the ash flow around Mt. Mantu covered an area 30
times larger than the original size of the volcano. Therefore, if the ash flow in the question
is 30 km, the original size of the volcano must be 30 times smaller, or 1 km. According to
Figure 1, a volcano with a diameter of 1 km will have an ash-cloud volume of approximately
54,000 km^3 . Choice (H) gives the best approximation of this value.
5 . B According to Figure 2, a volcano with a diameter of 30 km should have approximately
1,000,000 years between eruptions. Therefore, since this volcano erupted 500,000 years ago,
it will not erupt for another 1,000,000 − 500,000 = 500,000 years, as in (B).
Passage X
1 . D The words magnetic field strength don’t appear explicitly in the question, but they are
suggested by the word attract. Therefore, use Figure 2 to figure out the relationship between
the number of coils and the magnetic field strength. According to this Figure, the magnetic
field strength increases with increasing number of coils for all three curves shown.
Therefore, in order to get the strongest possible magnetic field, we will need the maximum
number of coils, or 200, as in (D).
2 . G Review the trends in Figure 2. As the number of coils increases, magnetic field strength
increases, which is why all curves show a positive slope. But the key identifies the
difference between each curve: The greater the current, the greater the magnetic field
strength. Choice (G) provides the correct relationship.
3 . B Find μ = 14 × 10−^5 in the key for Figure 3. Notice, though, that all three of these curves
follow the same trend: As solenoid length increases, L decreases and then levels off at the
end. Only (B) is consistent with this information.
4 . J According to Figure 3, as solenoid length increases, L decreases. The μ curves don’t follow
quite so consistent a relationship. Pick a point and see how these μ values relate to one
another. At a solenoid length of 0.02 m, the μ value associated with the largest L value is μ =
28 × 10−5. The μ value associated with the smallest L value is μ = 7 × 10−5 . Therefore, the
correct answer should have 28 × 10−5 as its first value and 7 × 10−5 as its last. Only (J)
works.
5 . D Find the point on Figure 2 that corresponds to 100 coils and a magnetic field strength of 300
