الفهرس 
ContentsOnly 14 pages are availabe for public view
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Abstract
A perfect superconductor is a material that exhibits two characteristic properties namely zero electrical resistivity and perfect diamagnetism when it is colled below a particular temperature called the critical temperature Tc. At higher temperatures it is a normal metal and usually is not a good conductor For example lead Pb tantalum Ta and tin Sn become superconductors while copper Cu silver Ag and gold Au which are much better conductors do not become superconductors.