作者billren (Yu)
看板NTU-Exam
标题[试题] 96下 郭博成 材料科学导论下 期末考
时间Tue Jun 17 19:49:32 2008
课程名称︰材料科学导论
课程性质︰必修
课程教师︰郭博成
开课学院:工学院
开课系所︰材料系
考试日期(年月日)︰2008/6/17
考试时限(分钟):150分钟
是否需发放奖励金:是
(如未明确表示,则不予发放)
试题 :
1.Why the magnetic moment of an atom in the magnetic material will oreien to
the applied magnetic field direction if the magnetic filed is large enough?
(10%)
2.Describe the change of domain configurations during magnetization for a
magnetic material.(10%)
3.Cite the major similarities and differences between ferromagnetic and ferrimagnetic
materials.(15%)
4.Cite the differences between type I and type II superconductors.(10%)
5.Explain why the resistivity of metal is increased woth temperature but the
resistivity of intrinsic semiconductor is decreased with increasing
temperature.(10%)
6.How does the electron structure of an isolated atom differ form that of a
solid material?(10%)
7.Some hypothetical metal is known to have an electrical resistivity of 4*10^-8
(Ω-m). Through a specimen of this mental that is 25mm thick is passed a
current of 30 A ; when a magnetic field of 0.75 tesla is simultaneously
imposed in a direction perpendicular to to that of the current, Hall voltage
of -1.26*10^-7 V is measured. Compute
(a) the electron mobility for this metal, and
(b) the number of free electrons per cubic meter. (10%)
8.Consider a parallel-plate capacitor having an area of 2500 mm^2 and aplate
separation of 2 mm, and with material of dielectric constant 4.0 positioned
between the plates.
(a)What is capacitance of this capacitor?
(b)Compute the electric field that must applied for a charge of 8.0*10^-9 C
to be stored on each plate (10%)
9.Briefly explain determines the characteristic color of (1) a metal and (2)
a transparent nonmetal. (15%)
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