課程名稱︰普通物理學乙下 課程性質︰必修 課程教師︰王建萬 開課學院： 開課系所︰農化系 考試日期（年月日）︰2012.4.25 考試時限（分鐘）：120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 12.0g blick with a charge of +10.0*10^5C is placed in an electric field E=(3000i-600j) N/C. What are the (a) magnitude and (b) direction (relative to the positive direction of the x axis) of the electrostatic force on the block? If the block is released from rest at the origin at time t=0, what are its (c)x and (d) y coordinates at t=2.00s? 2. Two isolated, concentric, conducting spherical shells have radii R1=0.400 m and R2=0.800m, uniform charges q1=+4.00μC and negligible thicknesses. What is the magnityde of the electric field E at radial distance (a) r=4.00m, (b) r=0.600m, and (c) r=0.200m? With V=0 at infinity, what is V at (d) r=4.00m, (e) r=0.800m, (f) r=0.600m, (g) r=0.400m, (h) r=0.200m and (i) r=0? 3. What is the current in a wire of radius R=4.00mm if the magnitude of the current density is given by (a)Ja=Jo r/R and (b) Jb=Jo(r/R)^2, and (c)Jc=Jo(1-r/R), in which r is the radial distance and Jo=8.00*10^4A/m^2? (d)which function maximizes the current density near the wire's surface? 4. An alpha particle can be produced in certain radioactive decays of nuclei and consists of two protons and two nejtrons. The particle has a charge of q=+2e and a mass of 4.00u , where u is the atomic mass unit, with 1u=1.66*10-27kg. Suppose an alpha particle travels in a circular path of radius 6.00cm in a uniform magnetic field with B=1.60T. Calculate (a)its speed, (b) its period of revolution, (c) its kinetic energy, and (d) the potential defference through which it eould habe to be accelerated to achieve this energy. 5. In Fig.1, (Holiday第九版Fig23-49) a solid sphere of radius a=2.50cm is concentric with a spherical conducting shell has a net charge q2=-q1. What is the magnitude of the electric field at radial distances (a) r=0 (b)r=a/2.00 (c)r=a (d)r=1.50a (e) r=2.20a and (f)r=4.00a? What is the net charge on the (g) inner and (h) outer surface of the shell? 6. In Fig.2, (課本Fig.25-28) a potential defference V=160V is across a capacitor arrangement with capacitors C1=10.0μF, and C3=3.00μF. What are (a) charge q1 (b) potenrial defference V1, and (c) stored energy U1 for capacitor 1, (d) q2 (e) V2 and (f) U2 for capacitor 2, and (g) q3 (h)V3,and (i) U3 for capacitor 3? 7. In Fig.3, (課本Fig.27-47) ε1=10.0V , ε2=15.0V, R1=150Ω , R2=300Ω, R3=450Ω. One point of the circuit is grounded (V=0). What are the (a)size and (b) direction (up or down) of the vurrent through resistor 1, the (c) size and (d) direction (left or right) of the current through resistor 2, and the (e) size and (f) direction of the current through resistor 3? (g) What is the electric potenrial at point A? 8. Fig.4 (課本Fig.23-53) shows a spherical shell with unitorm volume charge density ρ=1.80 nC/m^3, inner radius a = 12.0cm, and outer radius b=1.60a. What is the magnitude of the eletric field at radial destances (a)r=0, (b)r=a/2.00, (c)r=a (d) r=1.40a, (e)r=b, and (f) r=2.50b? --

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