課程名稱︰近代物理
課程性質︰電機系 系定必選
課程教師︰楊志忠
開課學院：電資學院
開課系所︰電機系
考試日期（年月日）︰2007/11/29
考試時限（分鐘）：170分
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
20簡答題 每題5分 請簡答
1.Consider symmetric quantum well(the barrier potential levels on the two
sides of the well layer are the same). (a)When the well width becomes lager,
will the quantized state number within the well be increased or decreased?
(b)Is it possible for the number of even states to be smaller than that of
odd states?
2.When an electron of kenetic energyE is moving toward a potential barrier of
potential hight U (E<<U) and the barrier thickness L (wuite large),the
tunneling probability is calculated to give 10^(-6).What would be estimated
tunneling probability when the U become 2U and the L become L/2?
3.what are the expectation values of electron positionin various energy states
of a quantum well with barrier potential height U and well width L?
4.By assuming the energy and momentum of a particle as the operator as
E=i(h/2Pi)d/dt and p=-i(h/2pi)▽ ,please derive the Schroedinger equation
from the law of energy conservation.
5.What is the complete set property of a set of eigenfunction in a potential
system?
6.What is the othornormal condition of a set of eigenfunction in a potential
system?
7.Explain the key concept Bohr used dor deriving the discrete Bohr electron
orbit in a hydrogen atom?
8.What is the physical meaning of Bohr radius?
9.What is an exiton in a semiconductor?
10.What is the energy difference between 2 neighboring energy states in a
hydrogen atom when the quantum number is extremely large?
11.How can we explain the discrepancy between quantum physics and classical
physics in electromagnetic radiation by using the hydrogen atom as an example?
12.how did people discover deuterium (氘)?
13.Please explain the concept of "coherence" in optic without using any
equation.
14.What is the major difference between spoteneous emission amd stimulated
emission?
15.Why is a 4-level system is better than a 2-level system in laser operation?
16.What is a resonance frequency in a resonance cavity?
17.How can a 2-photon absorbtion process occur without violating the energy
consevation law?
18.Please derive the kinetic energy level of a partical (mass=m)in a box(lenth=
L)?
19.When you measure the spoteneuous emission spectrum of an energy state to
obtain a spectral width of 100 Mhz, please estimate the average lifetime of
elcatron to stay in this energy states.
20.Please write down the uncertainty principles in the spatial and time
domains.
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