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Question 1
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
77% (02:18) correct
23%
(02:51) wrong
based on 124
sessions
History
Date
Time
Result
Not Attempted Yet
Question 2
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
80% (01:14) correct 20%
(01:24) wrong
based on 123
sessions
History
Date
Time
Result
Not Attempted Yet
Question 3
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
75%
(hard)
Question Stats:
43% (01:43) correct 57%
(01:39) wrong
based on 120
sessions
History
Date
Time
Result
Not Attempted Yet
Question 4
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
79% (00:33) correct 21%
(00:33) wrong
based on 102
sessions
History
Date
Time
Result
Not Attempted Yet
Heike Kamerlingh Onnes (1853–1926) a Dutch physicist discovered superconductivity in 1911. He used liquid helium as a coolant to study the electrical properties of metals at low temperatures. To everyone’s surprise, when mercury was cooled to about 4.2 kelvins, it suddenly lost all electrical resistance. This threshold is known as the critical temperature or \(T_{c}\). Other materials having ever higher critical temperatures were discovered slowly but surely during the first five decades of superconductivity research. All these superconductors were either pure metallic elements or intermetallic compounds (made of two or more metallic elements).
All this changed in 1986 with the discovery of high temperature superconductivity. During the first few years after this discovery, \(T_{c}\) values shot up, with mercury-barium-calcium-copper-oxide having a \(T_{c}\) of about 130K. This was a fantastically exciting time, but it soon became clear that the leading theory of how superconductivity arises does not explain the absence of resistance in these materials.
These compounds also pose a multitude of physical challenges. Initially, they were hard to make in either high-purity or single-crystal form, making the measurements of their fundamental properties difficult. In addition, the synthesis of wires is not easy: unlike the intermetallic superconductors, the individual grains that make up a piece of one of these oxides have to be aligned with respect to one another for the wire to have useful engineering properties. These problems left researchers and engineers wishing for a substance with the somewhat easier material properties of the intermetallic superconductors that also had a critical temperature significantly higher than 20K.
All this changed in 1986 with the discovery of high temperature superconductivity. During the first few years after this discovery, \(T_{c}\) values shot up, with mercury-barium-calcium-copper-oxide having a \(T_{c}\) of about 130K. This was a fantastically exciting time, but it soon became clear that the leading theory of how superconductivity arises does not explain the absence of resistance in these materials.
These compounds also pose a multitude of physical challenges. Initially, they were hard to make in either high-purity or single-crystal form, making the measurements of their fundamental properties difficult. In addition, the synthesis of wires is not easy: unlike the intermetallic superconductors, the individual grains that make up a piece of one of these oxides have to be aligned with respect to one another for the wire to have useful engineering properties. These problems left researchers and engineers wishing for a substance with the somewhat easier material properties of the intermetallic superconductors that also had a critical temperature significantly higher than 20K.
1. Which of the following is true about liquid helium?
A. It is the only substance used as a coolant
B. It can be used in low temperatures only.
C. It is used to lower the temperature of metals.
D. It is the best liquid used as a coolant.
E. It has a very low heat and thermal conductivity.
A. It is the only substance used as a coolant
B. It can be used in low temperatures only.
C. It is used to lower the temperature of metals.
D. It is the best liquid used as a coolant.
E. It has a very low heat and thermal conductivity.
2. Which of the following can be inferred from the first paragraph
A. Superconductivity was first discovered long before the nineteenth century but surfaced in 1911.
B. A temperature under which a material acts as a superconductor is called critical temperature.
C. No substance at a temperature less than 4.2 kelvins act as a superconductor.
D. Substances with extremely high temperatures can be easily converted into superconductors
E. Intermetallic substances can be easily superconducted as compared to pure metallic substance
A. Superconductivity was first discovered long before the nineteenth century but surfaced in 1911.
B. A temperature under which a material acts as a superconductor is called critical temperature.
C. No substance at a temperature less than 4.2 kelvins act as a superconductor.
D. Substances with extremely high temperatures can be easily converted into superconductors
E. Intermetallic substances can be easily superconducted as compared to pure metallic substance
3. All of the following can be inferred from the passage EXCEPT
A. When compared to pure metallic substances, measuring the physical properties of an intermetallic substance is challenging.
B. Synthesizing of wires is one of the critical steps of Superconductivity.
C. Intermetallic superconductors can have a critical temperature higher than 20K.
D. Late in the nineteenth century superconductivity became more challenging.
E. Electrical properties of metals vary with temperature.
A. When compared to pure metallic substances, measuring the physical properties of an intermetallic substance is challenging.
B. Synthesizing of wires is one of the critical steps of Superconductivity.
C. Intermetallic superconductors can have a critical temperature higher than 20K.
D. Late in the nineteenth century superconductivity became more challenging.
E. Electrical properties of metals vary with temperature.
4. Which of the following is the most likely topic of the passage?
A. The work of Heike Kamerlingh for superconductivity
B. The role of critical temperatures in Superconductivity
C. Nineteenth century and Superconductivity
D. The History and Challenges of Superconductivity
E. Challenges of Superconductivity
A. The work of Heike Kamerlingh for superconductivity
B. The role of critical temperatures in Superconductivity
C. Nineteenth century and Superconductivity
D. The History and Challenges of Superconductivity
E. Challenges of Superconductivity
10 Mar 2023, 03:20
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1. Which of the following is true about liquid helium?
Refer to the line in the passage "He used liquid helium as a coolant to study the electrical properties of metals at low temperatures"
A. It is the only substance used as a coolant ~ Incorrect, H.K.Onnes uses Helium as a coolant, but we cannot say that it was the only substance available to use as a coolant. May be other coolant were there, but they did not satisfy the research criterion of H.K.Onnes. They may be costly, less abundant, and due to other multiple reasons were not selected for the research.
B. It can be used in low temperatures only. ~ Incorrect, in the above statement Helium is used as a coolant, we know that metals were raised to lower temperature for superconductivity, but from this we cannot conclude that Helium can be used in low temperatures only. Also, coolant is one of the use of the Helium, may be other uses of Helium require it to be at higher temperature or room(natural) temperature greater than low temperature.
C. It is used to lower the temperature of metals. ~ Correct, this is the exactly mentioned in the above line that Helium is used to lower the temperature of metals to study their electrical properties. This is also confirmed by the line "To everyone’s surprise, when mercury was cooled to about 4.2 kelvins, it suddenly lost all electrical resistance." Here Helium as a coolant able to achieve the task of reducing the Mercury temperature to about 4.2 Kelvins.
D. It is the best liquid used as a coolant. ~ Incorrect, the use of adjective best is not used to describe Helium as a coolant. We don't know why H.K.Onnes uses Helium as a coolant may be it was easily available, less costly than other. There are multiple reasons why He chooses Helium as a coolant, we cannot certainly say that he chooses Helium because it is the best liquid.
E. It has a very low heat and thermal conductivity. ~ Incorrect, we don't know about the heat and thermal conductivity of the helium, it's use only as a coolant is discussed.
2. Which of the following can be inferred from the first paragraph
A. Superconductivity was first discovered long before the nineteenth century but surfaced in 1911. ~ Incorrect, it is mentioned in the first paragraph that H. K. Onnes discovered superconductivity in 1911. There is no mention that it was discovered earlier, but surfaced by H. K. Onnes .
B. A temperature under which a material acts as a superconductor is called critical temperature. ~ Correct, refer to the line "To everyone’s surprise, when mercury was cooled to about 4.2 kelvins, it suddenly lost all electrical resistance. This threshold is known as the critical temperature or Tc".
C. No substance at a temperature less than 4.2 kelvins act as a superconductor. ~ Incorrect, Mercury when cooled to about 4.2K lost all electrical resistance and act as a superconductor. So temperature of 4.2 Kelvins is the threshold for mercury as a metal. We don't know what are the threshold temperature for other metals.
D. Substances with extremely high temperatures can be easily converted into superconductors ~ Incorrect, as per the passage after the discovery of superconductivity by H .K. Onnes, other materials were discovered which has higher temperature than the threshold temperature of 4.2k . But, we cannot confirm that conversion of these materials into semiconductor became easier or not.
E. Intermetallic substances can be easily superconducted as compared to pure metallic substance ~ Incorrect, new superconductors which were discovered after mercury does have higher critical temperature. But we don't know between these newer superconductors intermetallic substance or metallic substance which can be easily superconducted.
3. All of the following can be inferred from the passage EXCEPT
A. When compared to pure metallic substances, measuring the physical properties of an intermetallic substance is challenging. ~ Correct, refer to the line "These compounds also pose a multitude of physical challenges. Initially, they were hard to make in either high-purity or single-crystal form, making the measurements of their fundamental properties difficult" . In this fundamental properties of intermetallic substance are mentioned, the fundamental properties is not equivalent to the physical properties. Also in the last line of the passage "These problems left researchers and engineers wishing for a substance with the somewhat easier material properties of the intermetallic superconductors that also had a critical temperature significantly higher than 20K." Material properties is mentioned which is equal to the chemical compostion and not the physical property of the intermetallic substance.
B. Synthesizing of wires is one of the critical steps of Superconductivity. ~ Incorrect, mentioned in the passage refer to the line "In addition, the synthesis of wires is not easy: unlike the intermetallic superconductors, the individual grains that make up a piece of one of these oxides have to be aligned with respect to one another for the wire to have useful engineering properties."
C. Intermetallic superconductors can have a critical temperature higher than 20K. ~Incorrect, mentioned in the passage refer to the line " During the first few years after this discovery, Tc values shot up, with mercury-barium-calcium-copper-oxide having a Tc of about 130K". So clearly intermetallic superconductors can have a Tc higher than 20k.
D. Late in the nineteenth century superconductivity became more challenging. ~ Incorrect, passage mentions that in 1986, with use of intermetallic compounds the threshold temperature value shot up, but these intermetallic compounds poses multitude of physical challenges. This is further confirm by last line "These problems left researchers and engineers wishing for a substance with the somewhat easier material properties of the intermetallic superconductors that also had a critical temperature significantly higher than 20K." So superconductivity has became more challenging in the late 19th century.
E. Electrical properties of metals vary with temperature. ~ Incorrect, as per the passage beyond a threshold temperature, metals lost all electrical resistance and became superconductor. Refer to the line "To everyone’s surprise, when mercury was cooled to about 4.2 kelvins, it suddenly lost all electrical resistance."
4. Which of the following is the most likely topic of the passage?
A. The work of Heike Kamerlingh for superconductivity ~ Incorrect, the work of H.K.Onnes is described to show how the discovery of Superconductivity is made by him. Later the passage transition to increasing the threshold temperature of intermetallic compounds and what are the challenges associated with these intermetallic compounds to be used as a semiconductor.
B. The role of critical temperatures in Superconductivity ~ Incorrect, author initially mentions that critical temperature is the threshold temperature for superconductivity. But by increasing the temperature in the intermetallic compounds, new problems related to material properties have arise.So, increasing the critical temperature is not the only criterion for supercondutivity.
C. Nineteenth century and Superconductivity ~ Incorrect, Passage mentions that the discovery of superconductivity was made in the 1911, but in later years it was discovered that the initial theory "how superconductivity arises" did not explain the physical challenges associated with the intermetallic compounds. Although passage mentions the Superconductivity during the timeline of 19th century, but it is not focussed on the timeline of the 19th century. It is more focussed on the challenges and the history of the Superconductivity.
D. The History and Challenges of Superconductivity ~ Correct, this statement completely describes the passage. Passage begins with a brief history of superconductivity, how it is discovered by H.K.Onnes by use of metal mercury and later during the 19th century other metallic and intermetallic compounds were discovered. After that physical challenges associated with usage of intermetallic compounds as semiconductors were mentioned.
E. Challenges of Superconductivity ~ Incorrect, between option D and E, D will be a more apt choice as passage begins with a brief history of superconductivity, how it is discovered by H.K.Onnes by use of metal mercury and later during the 19th century other metallic and intermetallic compounds were discovered. Although E covers the challenges of superconductivity mentioned in later parts of the passage, it fails to capture the history in the first paragraph.
Refer to the line in the passage "He used liquid helium as a coolant to study the electrical properties of metals at low temperatures"
A. It is the only substance used as a coolant ~ Incorrect, H.K.Onnes uses Helium as a coolant, but we cannot say that it was the only substance available to use as a coolant. May be other coolant were there, but they did not satisfy the research criterion of H.K.Onnes. They may be costly, less abundant, and due to other multiple reasons were not selected for the research.
B. It can be used in low temperatures only. ~ Incorrect, in the above statement Helium is used as a coolant, we know that metals were raised to lower temperature for superconductivity, but from this we cannot conclude that Helium can be used in low temperatures only. Also, coolant is one of the use of the Helium, may be other uses of Helium require it to be at higher temperature or room(natural) temperature greater than low temperature.
C. It is used to lower the temperature of metals. ~ Correct, this is the exactly mentioned in the above line that Helium is used to lower the temperature of metals to study their electrical properties. This is also confirmed by the line "To everyone’s surprise, when mercury was cooled to about 4.2 kelvins, it suddenly lost all electrical resistance." Here Helium as a coolant able to achieve the task of reducing the Mercury temperature to about 4.2 Kelvins.
D. It is the best liquid used as a coolant. ~ Incorrect, the use of adjective best is not used to describe Helium as a coolant. We don't know why H.K.Onnes uses Helium as a coolant may be it was easily available, less costly than other. There are multiple reasons why He chooses Helium as a coolant, we cannot certainly say that he chooses Helium because it is the best liquid.
E. It has a very low heat and thermal conductivity. ~ Incorrect, we don't know about the heat and thermal conductivity of the helium, it's use only as a coolant is discussed.
2. Which of the following can be inferred from the first paragraph
A. Superconductivity was first discovered long before the nineteenth century but surfaced in 1911. ~ Incorrect, it is mentioned in the first paragraph that H. K. Onnes discovered superconductivity in 1911. There is no mention that it was discovered earlier, but surfaced by H. K. Onnes .
B. A temperature under which a material acts as a superconductor is called critical temperature. ~ Correct, refer to the line "To everyone’s surprise, when mercury was cooled to about 4.2 kelvins, it suddenly lost all electrical resistance. This threshold is known as the critical temperature or Tc".
C. No substance at a temperature less than 4.2 kelvins act as a superconductor. ~ Incorrect, Mercury when cooled to about 4.2K lost all electrical resistance and act as a superconductor. So temperature of 4.2 Kelvins is the threshold for mercury as a metal. We don't know what are the threshold temperature for other metals.
D. Substances with extremely high temperatures can be easily converted into superconductors ~ Incorrect, as per the passage after the discovery of superconductivity by H .K. Onnes, other materials were discovered which has higher temperature than the threshold temperature of 4.2k . But, we cannot confirm that conversion of these materials into semiconductor became easier or not.
E. Intermetallic substances can be easily superconducted as compared to pure metallic substance ~ Incorrect, new superconductors which were discovered after mercury does have higher critical temperature. But we don't know between these newer superconductors intermetallic substance or metallic substance which can be easily superconducted.
3. All of the following can be inferred from the passage EXCEPT
A. When compared to pure metallic substances, measuring the physical properties of an intermetallic substance is challenging. ~ Correct, refer to the line "These compounds also pose a multitude of physical challenges. Initially, they were hard to make in either high-purity or single-crystal form, making the measurements of their fundamental properties difficult" . In this fundamental properties of intermetallic substance are mentioned, the fundamental properties is not equivalent to the physical properties. Also in the last line of the passage "These problems left researchers and engineers wishing for a substance with the somewhat easier material properties of the intermetallic superconductors that also had a critical temperature significantly higher than 20K." Material properties is mentioned which is equal to the chemical compostion and not the physical property of the intermetallic substance.
B. Synthesizing of wires is one of the critical steps of Superconductivity. ~ Incorrect, mentioned in the passage refer to the line "In addition, the synthesis of wires is not easy: unlike the intermetallic superconductors, the individual grains that make up a piece of one of these oxides have to be aligned with respect to one another for the wire to have useful engineering properties."
C. Intermetallic superconductors can have a critical temperature higher than 20K. ~Incorrect, mentioned in the passage refer to the line " During the first few years after this discovery, Tc values shot up, with mercury-barium-calcium-copper-oxide having a Tc of about 130K". So clearly intermetallic superconductors can have a Tc higher than 20k.
D. Late in the nineteenth century superconductivity became more challenging. ~ Incorrect, passage mentions that in 1986, with use of intermetallic compounds the threshold temperature value shot up, but these intermetallic compounds poses multitude of physical challenges. This is further confirm by last line "These problems left researchers and engineers wishing for a substance with the somewhat easier material properties of the intermetallic superconductors that also had a critical temperature significantly higher than 20K." So superconductivity has became more challenging in the late 19th century.
E. Electrical properties of metals vary with temperature. ~ Incorrect, as per the passage beyond a threshold temperature, metals lost all electrical resistance and became superconductor. Refer to the line "To everyone’s surprise, when mercury was cooled to about 4.2 kelvins, it suddenly lost all electrical resistance."
4. Which of the following is the most likely topic of the passage?
A. The work of Heike Kamerlingh for superconductivity ~ Incorrect, the work of H.K.Onnes is described to show how the discovery of Superconductivity is made by him. Later the passage transition to increasing the threshold temperature of intermetallic compounds and what are the challenges associated with these intermetallic compounds to be used as a semiconductor.
B. The role of critical temperatures in Superconductivity ~ Incorrect, author initially mentions that critical temperature is the threshold temperature for superconductivity. But by increasing the temperature in the intermetallic compounds, new problems related to material properties have arise.So, increasing the critical temperature is not the only criterion for supercondutivity.
C. Nineteenth century and Superconductivity ~ Incorrect, Passage mentions that the discovery of superconductivity was made in the 1911, but in later years it was discovered that the initial theory "how superconductivity arises" did not explain the physical challenges associated with the intermetallic compounds. Although passage mentions the Superconductivity during the timeline of 19th century, but it is not focussed on the timeline of the 19th century. It is more focussed on the challenges and the history of the Superconductivity.
D. The History and Challenges of Superconductivity ~ Correct, this statement completely describes the passage. Passage begins with a brief history of superconductivity, how it is discovered by H.K.Onnes by use of metal mercury and later during the 19th century other metallic and intermetallic compounds were discovered. After that physical challenges associated with usage of intermetallic compounds as semiconductors were mentioned.
E. Challenges of Superconductivity ~ Incorrect, between option D and E, D will be a more apt choice as passage begins with a brief history of superconductivity, how it is discovered by H.K.Onnes by use of metal mercury and later during the 19th century other metallic and intermetallic compounds were discovered. Although E covers the challenges of superconductivity mentioned in later parts of the passage, it fails to capture the history in the first paragraph.
10 Mar 2023, 08:45
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Explanation
1. Which of the following is true about liquid helium?
Explanation
The correct answer is C. Liquid helium is used as a coolant to lower the temperature of metals, as mentioned in the passage: "He used liquid helium as a coolant to study the electrical properties of metals at low temperatures."
A is incorrect because the passage doesn't say that liquid helium is the only substance used as a coolant.
B is incorrect because while liquid helium is used at low temperatures, it can also be used at higher temperatures.
D is incorrect because the passage doesn't make any comparison between liquid helium and other coolants to determine which is the best.
E is incorrect because the passage doesn't provide any information on the heat and thermal conductivity of liquid helium.
Answer: C
Explanation
The correct answer is C. Liquid helium is used as a coolant to lower the temperature of metals, as mentioned in the passage: "He used liquid helium as a coolant to study the electrical properties of metals at low temperatures."
A is incorrect because the passage doesn't say that liquid helium is the only substance used as a coolant.
B is incorrect because while liquid helium is used at low temperatures, it can also be used at higher temperatures.
D is incorrect because the passage doesn't make any comparison between liquid helium and other coolants to determine which is the best.
E is incorrect because the passage doesn't provide any information on the heat and thermal conductivity of liquid helium.
Answer: C
