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QUESTION BANK IN PHYSICS (B.TECH FIRST YEAR)

SUPERCONDUCTIVITY

1. Explain Meissner effect, type-I and type-II superconductors. (4) {JUN 15 [GNE]}
2. What is isotope effect? (2) {JUN 15 [PTU]}
3. Give a brief account of BCS theory of superconductivity. (3) {JUN 15 [PTU]}

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4. Give a brief account of occurrence of superconductivity using BCS theory. (3) {JUN 15 [PTU]}
5. What is the wavelength of an electromagnetic photon, which can break a Cooper pair in a material having critical temperature of 4K? (2) {Dec 14 [GNE]}
6. Derive London’s equations and give their significance.(4) {Dec 14 [GNE]}
7. Derive London’s equations and show that these equations can account for perfect diamagnetism property of an ideal superconductor. (4) {JUN 14 [GNE]}
8. What is the effect of magnetic field on superconductivity? Given a type-I superconductor with T_c = 7K and slope =-5x10^-3A/m at T_c. Estimate its critical field at 6K. (4) {JUN 14 [GNE]}

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9. What do you mean by Meissner effect? (2) {JUN
10. A superconducting state behaves according to which magnetic material in presence of applied magnetic field having magnitude less than critical value. (2) {JUN 14 [PTU]}
11. What do you understand by superconducting state? Under what conditions one can achieve it? (4) {Dec 2013 [PT
12. Why are type I superconductors not used for carrying conductors? (2) {Dec 2013 [PTU]}
13. What is Meissner effect? (2) {Dec 2008 [PTU]}

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14. Derive London equation and discuss how its solution led to Meissner effect. (4) {Dec 2013 [PTU]}
15. The penetration depth of mercury at 3.5K is about 750A. What will be the penetration if the critical temperature for mercury is 4.2K ? (4) {Dec 2013 [PTU]}
16. Enumerate the factors affecting superconductivity. (2) {Dec 2013 [GNE]}
17. The critical magnetic field for a superconductor at absolute zero is 9x10⁴ Am^-1 and at 6K is 5x10⁴ Am^-1. Find the critical temperature and energy required to break Cooper pair at absolute zero. (4) {Dec 2013 [GNE]}
18. Derive London’s equations and hence explain Meissner’s effect and flux quantization. (4) {Dec 2013 [GNE]}

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19. What is Cooper pair? (2) {Jun 2013 [GNE]}
20. Deduce London equations and define London penetration depth. (4) {Jun 2013 [GNE]}
21. What is Meissner Effect? Explain type-I and type-II superconductors. (4) {Dec 2012 [GNE]}
22. For a specimen of V₃Ga , the critical fields are 1.4x10⁶A/m & 4.2x10⁶ A/m at 14K and 13K respectively. Calculate the transition temperature and critical fields at 0K and 4.2K . (2) {Dec 2012 [GNE]}
23. Outline some experimental facts about superconductivity. (4) {Dec 2012}

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QUESTION BANK IN PHYSICS (B.TECH FIRST YEAR)

24. What are type-II superconductors? (2) {June 2012}
25. What is the physical phenomenon behind superconductivity? How successful is this in today’s context? (4) {June 2012}
26. Elaborate the main features of BCS theory. (4) {June 2012}
27. What are important features of BCS theory? (2) {Dec 2011}

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28. What is the physical mechanism behind Meissner Effect? (3) {Dec 2011}
29. Discuss London’s theory of superconductivity. (5) {Dec 2011}
30. What are the conditions for a material to be superconductor? (2) {June 2011}
31. Explain BCS theory of superconductivity. (4) {June 2011}
32. What are London Equations? Find the expression for penetration depth of a superconductor. (4) {June 2011}

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33. What is Meissner Effect? (2) {Dec 2010}
34. Explain the difference between type-I and type-II superconductors. Dec 2010}
35. Give the salient features of BCS theory of superconductors. (3) {Dec 2010}
36. Superconductors are perfectly diamagnetic. Explain. Dec 2010}
37. What is Cooper pair? (2) {June 2010}

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38. Discuss the important differences between type-I and type-II superconductors with the help of example and plots of magnetization (H). (3) {June 2010}
39. What is Meissner Effect? Further explain the effect of magnetic field on the superconducting state. (3) {June 2010}
40. Define London Penetration depth giving its expression. (2) {June 2010}
41. Draw graphs for hard and soft superconductors. (2) {Dec 2009}
42. Explain BCS theory of superconductivity. (5) {Dec 2009}

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43. Write down the relation between critical field and critical temperature in superconductors. (2) {June 2009}
44. Plot the graphs for type-I and type-II superconductors. (2) {June 2009}
45. Derive & explain “the London equations and calculate the expression for the Penetration depth. (4) {June 2009}
46. What do you understand by penetration in the superconductors? (2) { Dec 2008}
47. What do you mean by coherence length in context with superconductors? (2) {Dec 2008}

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48. Define Levitation effect and explain the various factors that can destroy the superconductivity. (4) {Dec 2008}
49. Explain the BCS theory of superconductivity. (4)
50. Superconductors are perfectly diamagnetic in nature? (2) {May 2008}
51. What is critical field? Write down the expression for H_c and differentiate between type-I and type-II superconductors. (4) {May 2008}
52. Derive first London’s equation and give its physical significance. (4) {May 2008}

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53. State Meissner effect of superconductivity. (2) {Dec 2007}
54. What is London’s penetration depth? How does it vary with temperature? (4) {Dec 2007}
55. Define Cooper Pair. Calculate the wavelength of a photon, which will be required to break a Cooper Pair in a superconductor (Zr) for which T_c =0.56K . (4) {Dec 2007}

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QUESTION BANK IN PHYSICS (B.TECH FIRST YEAR)

56. Write the formula for variation of magnetic field intensity with temperature. (2) {May 2007}

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57. What is superconductivity? What are the differences between type-I and type-II superconductors? A type-I superconductor with T_c=7K has slope dB/dT_c =-25mTK^-1 at T_c . Estimate its critical field at 6K. (8) {May 2007}
58. What are Cooper Pairs? (2) {Dec 2006}
59. What are type I and type II superconductors? Explain. (3) {Dec 2006}
60. For Hg (mercury), the critical temperature at which the superconductivity ensues with zero applied magnetic fields is 4.15K . The critical applied magnetic field at which superconductivity will not take place at any temperature is 0.0417 . Find the applied magnetic field that will stop the superconductivity at 2.2K . (8) {Dec 2006}
61. What is Meissner Effect? (2) {May 2006}

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62. What do you understand by type-I and type-II superconductors? Give BCS theory of superconductivity. (8)
63. Discuss London’s theory of superconductivity. (2)
64. What are Cooper pairs? (2) {Dec2005}
65. What do you understand by type-I and type-II superconductors? (8)
66. What is the effect of magnetic field on superconductivity? (2) {May 2005}

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67. What is Meissner Effect? Show how London equations lead to this effect. (1,4) {May 2005}
68. A type-1 superconductor with has slope dB/dT_c =-25mTK^-1 at T_c. Estimate its critical field at 6K. (3)/{May 2005}
69. What is Meissner effect? (2) {Dec 2004 }
70. What is superconductivity? What are the differences between type-I and type-II superconductors? A type-1 superconductor with T_c=7K has slope dB/dT_c at T_c. Estimate its critical field at 6K. (2,3,3) {Dec 2004}
71. Metals, which are very good conductors at normal temperatures do not show superconducting behaviour. Why? (2) {May 2004 }

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72. Distinguish between type-I and type-II superconductors. Briefly discuss the BCS theory of superconductivity. (5) {May 2004}
73. State and explain Meissner Effect. How do London equations account for this effect? (3) {May 2004}
74. What are Cooper pairs? (2) {Dec2003}

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