Sajjad1994
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.
1. According to the passage, which of the following can be inferred about MgB2
A. It is the best among all superconductors
B. It can be formed without boron fiber
C. It cannot be formed without boron fiber
D. It is the only emerging superconductor
E. The process to make MgB2 is costly
2. According to the passage, it can be concluded about boron fiber that:
A. It is the only substance required to form MgB2
B. It is a type of liquid substance
C. It is a type of solid substance
D. It is available in lengths of hundreds of meters and diameters ranging from 0.1 to 0.3 millimeters
E. It has usually large diameters ranging from 1 to 3 millimeter
3. It can be inferred from the passage that
A. 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
D. Wire segments of MgB2 cannot be used practically.
E. Wires segments of MgB2 are the most efficient among all available in the market
4. The primary purpose of the passage is:
A. to describe the history of MgB2
B. introduce and detail MgB2 and how it can be formed and made useful
C. detail how the wire segments work in a superconductor called MgB2
D. to reason how boron fiber can be used to make MgB2 and its wire segments
E. enlist different procedures and techniques to form MgB2 and its wire segments
Donate and Help! - Pakistan Flood Relief donation drive.Please donate to flood-affected people in Pakistan
Flood has affected more than 30 million people in Pakistan.
Click here for Details and donation links Question 1
1. According to the passage, which of the following can be inferred about MgB2
A. It is the best among all superconductors- This cannot be inferred. This is an extreme statement
B. It can be formed without boron fiber- We have no evidence to support this inference from the passage
C. It cannot be formed without boron fiber- This is the correct answer. This can be inferred from the statement- 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.D. It is the only emerging superconductor- We cannot infer that it is the only emerging superconductor. We can rather say that it is an emerging superconductor
E. The process to make MgB2 is costly- This also cannot be inferred.
Question 2
2. According to the passage, it can be concluded about boron fiber that:
A. It is the only substance required to form MgB2- This is wrong as boron fiber alone cannot form MgB2
B. It is a type of liquid substance- This cannot be concluded about boron fiber
C. It is a type of solid substance- This can be concluded as the passage states that- boron fibers that can be purchased in lengths of hundreds of meters i.e. it is solid material. This is the correct answer.D. It is available in lengths of hundreds of meters and diameters ranging from 0.1 to 0.3 millimeters- We cannot be sure of the diameter here as the diameter given is for the filament used in application and not of boron fiber.
E. It has usually large diameters ranging from 1 to 3 millimeter- This cannot be concluded about boron fiber.
Question 3
3. It can be inferred from the passage that
A. Superconductivity is impossible without wire segments- This cannot be inferred from the passage
B. Measuring the physical characteristics of MgB2 is impossible without wire segments- Wire segments help to measure physical characteristics. But we cannot infer that physical characteristics of MgB2 cannot be measured without wire segments.
C. Powder in a tube is the only method of making wire segments- This is one of the method and not the only method
D. Wire segments of MgB2 cannot be used practically.- The passage clearly states that MgB2 application is not practical yet. This is the correct answer.E. Wires segments of MgB2 are the most efficient among all available in the market- This cannot be inferred.
Question 4
4. The primary purpose of the passage is:
A. to describe the history of MgB2- This is not the primary purpose
B. introduce and detail MgB2 and how it can be formed and made useful- This is limited in scope
C. detail how the wire segments work in a superconductor called MgB2- This is limited in scope
D. to reason how boron fiber can be used to make MgB2 and its wire segments- The primary purpose is not to reason
E. enlist different procedures and techniques to form MgB2 and its wire segments- This is the primary purpose of the passage. It covers the entire gist of passage. This is the correct answer