Bunuel wrote:
Physicist: A kilogram of antimatter mixed with a kilogram of matter would, through their mutual annihilation, release half as much energy as all the gasoline burned in the United States in 2005. But this process will never provide a practical means of generating energy: no known natural sources of antimatter are available, and the most efficient antimatter generator now in existence would have to run for 100 trillion years to make a kilogram of antimatter.
Which of the following is an assumption required by the physicist’s argument?
A. No other fuel could release as much energy per kilogram as antimatter when it is mixed with matter.
B. Present physics indicates that antimatter is unlikely to exist anywhere in large enough quantities to be usable as fuel.
C. No antimatter has yet been found in large enough quantities to be perceived by the naked eye (without magnifying instruments).
D. We will never, in the future, build an antimatter generator efficient enough to produce, within a practical amount of time, a sufficient amount to be practical as a fuel.
E. Making a kilogram of antimatter would take less than half as much energy as was released by all the gasoline burned in the United States in 2005.
Conclusion of the argument: The process of mixing matter and antimatter to produce energy
will never provide a practical means of generating energy.
Supporting Evidence: No known natural sources of antimatter are available, and the most efficient antimatter generator
now in existence would have to run for 100 trillion years to make a kilogram of antimatter.
Note the use of "will" in the conclusion. Hence, the author draws a very strong conclusion, that the process will never provide a practical means of generating energy, and in concluding the argument, the author assumes that the technology or generator now in existence cannot be enhanced beyond its current capacity. In addition, the author also assumes that all natural sources of antimatter are known to us.
Answer Choice EliminationA. No other fuel could release as much energy per kilogram as antimatter when it is mixed with matter.This assumption is not necessary for the physicist's argument. Even if other fuels could release as much energy per kilogram as antimatter, it wouldn't affect the conclusion as the conclusion revolves around the process of mixing matter and antimatter and doesn't concern other fuels. Hence, we can eliminate A.
B. Present physics indicates that antimatter is unlikely to exist anywhere in large enough quantities to be usable as fuel.This option strengthens the argument however is not a necessary assumption. The passage already outlines that there are no natural sources of antimatter available. Whether physics indicates that information (that antimatter is unlikely to exist anywhere in large enough quantities to be usable as fuel) or not has no bearing on the conclusion. It can be well possible that antimatter has no physical proof yet.
C. No antimatter has yet been found in large enough quantities to be perceived by the naked eye (without magnifying instruments).This option is not relevant to the argument's conclusion. Hence, we can eliminate B.
D. We will never, in the future, build an antimatter generator efficient enough to produce, within a practical amount of time, a sufficient amount to be practical as a fuel.This is indeed what the author assumes. The author concludes that "
the most efficient antimatter generator now in existence would have to run for 100 trillion". Hence the author concludes something very generic ("
..produce energy will never provide a practical means..") based on the current scenario. Hence, this is the missing link.
E. Making a kilogram of antimatter would take less than half as much energy as was released by all the gasoline burned in the United States in 2005.This assumption is not necessary for the physicist's argument. Energy consumption doesn't pay a huge role in drawing the conclusion. Eliminate E.
Option D