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Physics Essay Example


Published on

Topic: Superconductors and their real life applications as a theory of knowledge
Type: Essay
Subject: Physics
Academic Level: Undergraduate 1-2
Style: MLA
Language: English (U.S)
Number of Pages: 6 (double-spaced, Times New Roman, Font 12)
Number of sources: 5

Task Details:
1) Define superconductors;
2) Discuss their properties;
3) Describe how they can be utilized to solve various real life problems.

Published in: Science

Physics Essay Example

  1. 1. Surname !1 Topic Superconductors and their real life applications as a theory of knowledge Type Essay Level Undergraduate 1-2 Style MLA Sources 5 Description Define superconductors; discuss their properties; describe how they can be utilized to solve various real life problems Spacing 2 Pages 6
  2. 2. Surname !2 Name Course Instructor Date Superconductors Introduction Superconductors are materials that conduct electricity at adequately low temperatures. When the temperatures of a superconductor gradually reduce, the resistance also drops slowly just like in an ordinary conductor. However, the resistance of a superconductor suddenly drops to zero at a temperature commonly known as the transition temperature or critical temperature (K0/ Tc). For any temperature below the critical temperature, the resistance of the superconductor remains zero. The critical temperature (Tc) of novel superconductors varies widely from absolute zero to over 100K for some recently developed compounds of copper-oxide. The graph below shows the behavior of a superconductor (Rex 35). !
  3. 3. Surname !3 Figure 1: Properties of Superconductors Superconductors are in two groups according to their properties. They are type I and type II semiconductors. All the superconductors except Niobium form the type I category. Niobium and its alloys and chemical compounds form type II, which also consist of the high-Tc superconductors. One major factor that differentiates the two is their response to the magnetic effect. Type-I superconductors also exhibit the Meissner effect (Schmidt 6-7). Type-I semiconductors During the magnetization of a type-I superconductor, the applied magnetic field (external magnetic field Ho) causes no change to the induction inside the material (B=0). However, as the value of Ho reaches the value Hcm, the superconductivity of the material gets destroyed. The applied magnetic field penetrates the material, and the values of B and Ho becomes equal. The magnetic induction B and magnetic field Ho acquire a relation governed by the equation (Annett 57-59). The term represented by M stands for the magnetic moment per unit volume. The field lines outside any superconductor are tangential to its surface. The lines of induction B1 becomes closed and continuous. The property of the material satisfies the property that . The second property of the magnetic material is that when the superconductor gets in an external magnetic field, a current flows near its surface. When Maxwell's Equations find use on the above condition, one observes an unusual situation. Only the surface current occurs, making the internal flow be zero. It is vital to note that the surface current only exists
  4. 4. Surname !4 when the superconducting material finds a way to the inside of an external magnetic field. In a case where the external field does not exist, the material would create an own field in the superconductor. The latter condition is impossible. Meissner effect is also present in the type I semiconductors. When a magnetic field gets applied to this kind of superconductor, it expels the magnetic field, making the area of the material zero. Compared to an average or real metal, when an external magnetic field impacts on type I, the internal field becomes a constant. The above property shows that the superconductors are unique. The Meissner effect is demonstrated by cooling a high Tc superconductor and placing the permanent magnet on top of the superconductor. The permanent magnet gets repelled and levitated (Wesche 89). Physicists have tried to explain the levitation of the magnet. According to Poole, Horacio, and Creswick, the magnet perceives its mirror image in the superconductor as a magnet floating on the top of an identical magnet (10). It results in a distorted picture of the magnet at the edges of the superconductor. The whole situation balances the two magnets that would be impossible in the absence of physical force holding the two magnets apart. Therefore, the observation of the superconductor on a magnet leaves puzzle worth seeking an answer. In the setup, when one magnet gets nudged, it springs back to its original position. However, the demonstration of the experiment has never been right. Most of those researchers who carry out the levitation experiment tend to hold the magnet over the superconductor rather than letting it go. They only do it to levitate the magnet stable. However, if the magnet gets released at this point, it remains
  5. 5. Surname !5 stable. Removing the magnet and then releasing it back over the superconductor levitates it stably without the need to thrust it in the direction of the superconductor. Type II semiconductors The superconductors of type II varies from type I. They do not show the Meissner effect. When subjected to magnet field, it penetrates the materials in an extraordinary manner. Under the influence of an external magnetic field, the content rejects and pushes the field out because magnetic induction in the interior of the material is zero. However, when the area increases to an absolute value, there is an observation of a finite value of induction. The field at which induction get first recorded is called the lower particular area (HCl). When the magnetic field increases further, the general field in the material equals to the external field Ho and the material goes back to the normal state. The value of the area at which the material goes back to normal is called the upper critical field (Hcu). When the field exceeds the upper critical field superconductivity, it remains at the top as a thin surface of the material. When the value of the external field equals to Ho=1.69Hcu, the superconductivity in the surface layer get destroyed (Ginsberg 183). Application of semiconductors After the discovery of the superconductors by Kamerlingh Onnes, other scientists began to learn many practical applications for the new strange phenomenon. Using the superconductors facilitated large currents with no energy loss; hence, created powerful superconducting magnets. Large resistive magnets got replaced by smaller superconducting magnets. Generators with superconductor windings generated power with less equipment and little energy. Other promising applications of superconductors are in electrical transmission. Superconductors conduct
  6. 6. Surname !6 electricity with zero resistance; hence, no loss of power. With the current transmission lines, there is a substantial loss of electrical energy through heat generation and the charging duration of the capacitors due to the resistance of the joining metal films. Electrical transmission line using superconducting cables transport electric power with little power loss over long distances. However, this phenomenon is possible if a cooling mechanism gets devised. In the field of electronics, superconductors are very promising. The reduction of the sizes and increased speed of computer chips find limitations in the excessive generation of heat and charging time of capacitors. When using superconductors, the result may be more densely packed chips with high speeds of transmitting information. In the field of digital electronics, logic gates with delays of 13 picoseconds and switching time of 9 picoseconds have gone through successful practical demonstration. Other gadgets such as microwave detectors, SQUIDS, magnetometers and stable voltage sources are made more sensitive by the application of the Josephson junctions. In the transportation sector, the superconductors find use in the construction of levitated trains. In Japan, successful prototypes of the trains were constructed using Helium as a refrigerant. In the health sector, the Magnetic Resonance Imaging (MRI) plays a crucial role in diagnostic medicine. Superconductors find use in the powerful magnetic fields required for the MRI. A closer observation of the current trend of the development of the superconductors reveals that their new applications increase with a rise in critical temperatures. If superconductors with critical temperatures equal to room temperatures, then more superconducting devices will come into existence. Other devices that use superconductors include:
  7. 7. Surname !7 Superconductor transformers Superconductors make the transformer windings, thus reducing power losses. The sizes of the transformers get small, and they become portable. A transformer of 2000 to 3000mW gets manufactured with a reduced size. Electric motors and generators In the production of electrical machines, motors and generators, high efficiency and light weight are possible if superconductors can be utilized. The use of adamant magnetic fields and coils with no electric losses is a fascinating phenomenon to the area of power engineering. However, even the existing superconductors experience losses when used with low frequency alternating current. The problem gets the solution when newly discovered materials get used.
  8. 8. Surname !8 Superconducting breakers and fuse Thin-film superconductors find use in preparation of circuit breakers and switches. After a current of more than critical density has passed through a thin-insulated superconductor film, they have the capability to go back to the normal state. Using such films is more efficient than the regular electric fuses. It is possible to regulate the intensity of current by appropriately choosing the material for the film. When using the films as a circuit breaker, one should select a long film. The moment of transition must be at the normal state and the resistance made high (Ginsberg 39). Magnetic Mirror and Superconducting Bearing The zero magnetic induction, responsible for magnetic levitation finds application as frictionless bearings. In an individual levitation experiment, a horizontal bar magnet got suspended from a flexible chain and lowered over a sheet of lead cooled to the superconducting state. As the magnet approached the superconducting sheet, the supporting chain became floppy and formed a loop below the magnet. It remained in the suspended state above the sheet. In this regard, the magnetic field of the magnet approaching induced a current in the superconductor's surface. Since there were zero resistance, the persisting current, and its field repelled the bar magnet’s current (Poole, Horacio and Creswick 130). Therefore, the superconducting sheet acts as a mirror that reflects the attraction; hence forming its image. With proper design, a two-dimensional shaft bearing and three-dimensional support of a floating sphere get constructed. Other arrangements of superconductors get applications in superconducting gyroscope having spherical rotor than spins for months without stopping. The
  9. 9. Surname !9 phenomenon demonstrates an almost frictionless condition. Thus, superconductors as an area of knowledge is essential in our day to day operations as discussed above, especially in the field of science. In this regard, more input is required to maximize the real life output that can potentially be drawn from this area for the benefit of all.
  10. 10. Surname !10 Work Cited Annett, F. James. Superconductivity, Superfluids, and Condensates. Oxford: OUP Oxford, 2004. Print. Ginsberg, M. Donald. Physical Properties of High-Temperature Superconductors. Singapore: World Scientific, 1996. Print. Poole, P. Charles, et al. Superconductivity. Taramani: Elsevier, 2014. Print. Rex, Andrew. Commonly Asked Questions in Physics. Boca Raton: CRC Press, 2014. Print. Schmidt. The Physics of Superconductors: Introduction to Fundamentals and Applications. Berlin: Springer Science & Business Media. , 2013. Print. Wesche, Rainer. Physical Properties of High-Temperature Superconductors. New Jersey: John Wiley & Sons, 2015. Print.