Registration no. - 521134660
B. A. – 4th Semester –Spring Drive 2013
Subject Name: Foundation in Science and Technology.
Subject code: BAC 401
4 credits (60 marks)
Que1. Outline the risks of nuclear fissions. (10 marks)
Ans -Division of a heavy atomic nucleus into two fragments of roughly equal mass, accompanied by the release of a large amount of energy, the binding energy of the subatomic particles.
Top: Uranium-235 combines with a neutron to form an unstable intermediate, which quickly splits into barium-144 and krypton-89 plus three neutrons in the process of nuclear fission. Bottom: Deuterium and tritium combine by nuclear fusion to form helium plus a neutron.The energy released in the fission of one uranium nucleus is about 50 million times greater than that released when a carbon atom combines with oxygen atoms in the burning of coal. The energy appears as kinetic energy of the fragments, which converts to thermal energy as the fragments collide in matter and slow down. Fission also releases two or three free neutrons. The free neutrons can bombard other nuclei, leading to a series of fissions called a chain reaction. The energy released from nuclear fission is used to generate electricity, to propel ships and submarines, and is a source of the vast destructive power of nuclear weapons. In economics and finance, an allowance for the hazard (risk) in an investment or loan. Default risk refers to the chance that a borrower will not repay a loan. If a banker believes that a borrower may not repay a loan, the banker will charge the true interest plus a premium for the default risk, the premium depending on the degree of presumed risk. All stock investment carries an implicit risk since there is no guarantee of return on investment. Trading or variability risk is the amount that the return may vary, up or down, from the expected return on investment.
Que2. Comment on semiconductor devices and their usage. (10 marks) Ans - A semiconductor is a material that has an electrical conductivity due to flowing electrons (as opposed to ionic conductivity) which is intermediate in magnitude between that of a conductor and an insulator.
1. Semiconductor devices are all around us. They can be found in just about every commercial product we touch, from the family car to the pocket calculator. Semiconductor devices are contained in television sets, portable radios, stereo equipment, and much more. 2. Science and industry also rely heavily on semiconductor devices. Research laboratories use these devices in all sorts of electronic instruments to perform tests, measurements, and numerous other experimental tasks. Industrial control systems (such as those used to manufacture automobiles) and automatic telephone exchanges also use semiconductors. Even today heavy-duty versions of the solid-state rectifier diode are being use to convert large amounts of power for electric railroads. Of the many different applications for solid-state devices, space systems, computers, and data processing equipment are some of the largest consumers. 3. The various types of modem military equipment are literally loaded with semiconductor devices. Many radars, communication, and airborne equipment are transistorized. Data display systems, data processing units, computers, and aircraft guidance-control assemblies are also good examples of electronic equipments that use semiconductor devices. All of the specific applications of semiconductor devices would make a long impressive list. The fact is, semiconductors are being used extensively in commercial products, industry, and the military.
Que3. In a total system approach, what are the various factors which should be kept in mind while planning a large dam or a thermal power station? (10 marks) Ans -
Que4. What are the requisites of self – reliance? (10 marks) Ans - Self-reliance is being independent,...