Free Practice Question
RC · Reading Comprehension
605-655
Short Passage - Science
Reading Passage
Within a couple of weeks after the announcement of superconductivity in MgB2, we had devised a technique for making wire segments of this remarkable superconductor. MgB2 can be formed by reacting magnesium vapor with boron, a process that can take place within hours at temperatures near 1,000 degrees Celsius: the boron essentially sucks the magnesium vapor out of the environment and becomes MgB2. This process works with boron fibers that can be purchased in lengths of hundreds of meters; it has been applied to filaments with starting diameters ranging from 0.1 to 0.3 millimeter.
Wire segments such as these are very useful for basic research, allowing for the measurement of the intrinsic physical properties of MgB2. Before such wire segments could be used in practical applications, they would need to have a conductive, malleable sheath to provide structural support. A suitable sheath has not yet been developed.
A more common method of wire synthesis is called “powder in a tube.” This technique involves pouring powdered magnesium and boron or powdered MgB2 into a tube, drawing the tube into a wire, and then reacting or annealing the wire to produce a solid structure. This technique has produced research samples that range from tens to hundreds of meters long. Despite MgB2 being a rather young superconductor, companies have been taking notice and are working toward commercializing it. Examples include Diboride Conductors and Hyper Tech Research, which are small companies focusing on making and improving the properties of MgB2 wires.
Wire segments such as these are very useful for basic research, allowing for the measurement of the intrinsic physical properties of MgB2. Before such wire segments could be used in practical applications, they would need to have a conductive, malleable sheath to provide structural support. A suitable sheath has not yet been developed.
A more common method of wire synthesis is called “powder in a tube.” This technique involves pouring powdered magnesium and boron or powdered MgB2 into a tube, drawing the tube into a wire, and then reacting or annealing the wire to produce a solid structure. This technique has produced research samples that range from tens to hundreds of meters long. Despite MgB2 being a rather young superconductor, companies have been taking notice and are working toward commercializing it. Examples include Diboride Conductors and Hyper Tech Research, which are small companies focusing on making and improving the properties of MgB2 wires.
It can be inferred from the passage that
Answer Choices
Correct answer marked belowA
Superconductivity is impossible without wire segments
B
Measuring the physical characteristics of MgB2 is impossible without wire segments
C
Powder in a tube is the only method of making wire segments
Wire segments of MgB2 cannot be used practically.
Correct
E
Wires segments of MgB2 are the most efficient among all available in the market
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Your ability to understand a passage, its structure, and what the author is really saying. At the 605-655 level, accuracy and speed both matter.
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Difficulty
605-655
Type
RC
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