課程名稱︰普通物理學甲下
課程性質︰系定必修
課程教師︰高涌泉
開課學院：理學院
開課系所︰物理系
考試日期（年月日）︰2011/6/21
考試時限（分鐘）：100分鐘
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
1.(a)(10%)It is said that the laws of electrodynamics are inconsistent without
the displacement current. Explain why.
(b)(10%)Consider the RC circuit shown in Fig.1.
Switch S is closed at time t=0. Calculate the displacement current in the
capacitor as a funtion of time.
R
┌───／＼／＼／───┐
│ │
│ ╲
─┴─ S
C ─┬─ │
│ │
│ │ │
└─────┤├────┘
│
ε
Fig.1.
(c)(10%)Consider Fig.1. again. This time the switch is closed. At some time,
the switch is opened. What is the displacement current.
2.(10%)Consider an RLC circuit. The energy is given by
2 2
LI Q
E = ── + ── .
2 2C
Show that the rate of change of this energy is equal to the power loss in
the resistor( the ohmic heating power).
3.(10%)Consider a standing EM wave for which the electric field is
→ ^
E = E sin(kx)cos(ωt) j .
0
(a)What is the magnetic field?
(b)What is the Poynting vector?
4.(25%)Explain the following:
(a)Bohr magneton
(b)Paramagnetism
(c)Meissner effect
(d)Dipole radiation
(e)Malus's law
5.(15%)It was argued in the class that if a quantum particle is to be cofined in a
potential well, the particle must have a very definite energy (eigen energy)
What is the argument?
6.(10%)Seven electrons are in an infintely deep 1-dimensional potential well of
width L.
(a)What is the lowest possible energy for this system?
(b)What is the next highest energy value?
(In both parts, ignore Coulomb interations between r=the electrons.)
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