課程名稱︰普通物理
課程性質︰土木系必修
課程教師︰楊忠喜
開課學院：工學院
開課系所︰土木系
考試日期（年月日）︰2010/03/15
考試時限（分鐘）：120
是否需發放獎勵金：是 謝謝
（如未明確表示，則不予發放）
試題 :
1. Charge Q is on the y axis a distance A from the origin and charge q in on
the x axis a distance d from the origin. Find the value of d in terms of A
for which the x component of the force on q is the greatest.
Ans: d=A/√2
2. A solid nonconducting sphere of radius R has a nonuniform charge
distribution of volume charge density ρ=Ar , where A is a constant and r is
the distance from the center of the sphere. The total charge on the sphere
is Q.
(a) E(R/2)=? Ans: Q/16πεR^2
(b) if V(∞)=0 find V(R/3) Ans: 107Q/324επR
(c) find the total electrostatic potential energy V=? Ans: Q^2 /7πεR
3. 作圖:畫出電雙極之電力線和等電位面圖形
4. The dipole moment of a dipole is a 300 N/C electric field is initially
perpendicular to the field, but it rotates so it is in the same direction as
the field. If the moment has a magnitude of 2*10^-9 C*m , find the work done
by the field
Ans: 6×10^-7 J
5. What is the magnitude of the electric field at the point(3,-2,4)(m) if the
eletric potential is given by V=6xyz^2 , where V is in volts.
Ans: 450 V/n
6. Each of the four 25μF capacitors shown is initially uncharged. How many
coulombs of charge pass through the ammeter A after the switch is closed?
＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿∥＿＿＿
∣ ∣ ∣
∣ ∣ ∣
∣ = =
400V∣ ∣ ∣
∣ ∣ ∣
∣＿＿＿＿＿＿ A ＿＿＿＿＿＿＿＿＿ ∣＿＿∥＿＿＿∣
Ans: 0.133 C
7. An air-filled parallel-plate capacitor has a capacitance of 1pF. The plate
separation is then doubled and a wax dielectric is inserted., completely
filling the space between the plates. As a result, the capacitance becomes
2pF. Find the dielectric constant of the wax.
Ans: κ= 4
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※ 編輯: goldemruler 來自: 203.70.94.68 (04/25 02:04)