2020 Electromagnetic Field(Shandong University) 最新满分章节测试答案

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本课程起止时间为:2020-05-06到2020-08-15
本篇答案更新状态:已完结

Chapter I-A Physical Basis of Electromagnetic Field Exam of Vector and Filed Analysis

1、 问题:A scalar  field, ,along the direction of vector ,the directional derivative at the point M(2,-1,1) is
选项：
A:
B:
C:-2
D:
答案: 【】

2、 问题:,rot
选项：
A:0
B:3
C:r
D:
答案: 【0】

3、 问题:A  vector  field is . There is a closed sphere with the spherical equation . The flux from interior to outside of the sphere is
选项：
A:0
B:
C:
D:
答案: 【】

4、 问题:The divergence of a vector field  is
选项：
A:0
B:15
C:
D:
答案: 【15】

5、 问题:u is any scalar field, the curl of   is
选项：
A:0
B:
C:x \vec{i} +y \vec{j}+z \vec{k}
D:
答案: 【0】

Chapter I–B Physical Basis of Electromagnetic Field Exam of Electromagnetic Field Soure

1、 问题:A  line charge density is given as   in the  arc line with a radius of a and a center angle of ， find the totel  quantity is
选项：
A:
B:
C:
D:
答案: 【】

2、 问题:Sheet charge density is given in cylindrical  coordinates as  in the regin ;for ,,find  the charge quantity of  the surface  z=0.1m.
选项：
A:
B:
C:
D:
答案: 【】

3、 问题:Calculate the total charge with the volume charge density  in  universe
选项：
A:6.28C
B:3.14C
C:1.57C
D:12.56C
答案: 【6.28C】

4、 问题:Which description of current density  is right?
选项：
A:The current density is the amount of charge passing through the unit area vertically in unit time.
B:The current density is the amount of charge passing through any cross section in unit time.
C:The direction of current density is the direction of positron motion.
D:The direction of current density is the direction of electron  motion
答案: 【The current density is the amount of charge passing through the unit area vertically in unit time.;
The direction of current density is the direction of positron motion.】

5、 问题:About the line current, which following description is right?
选项：
A:Line current is a scalar.
B:Line current is a vector.
C:Line current describes the motion of the charge in the wire.
D:Line current only moves in or against the direction of  the wire.
答案: 【Line current is a scalar.;
Line current describes the motion of the charge in the wire.;
Line current only moves in or against the direction of  the wire.】

Chapter I–C Physical Basis of Electromagnetic Field Exam of Electric Field Intensity and Polarzatio

1、 问题:It is known that the charge density on the uniformly distributed surface of the semicircle with radius R as shown in the figure is . Assuming that the axial length of the semicircle is infinite and placed in vacuum, the electric field intensity E on the axis of the semicircle is
选项：
A:
B:
C:
D:
答案: 【】

2、 问题:If the inner and outer radii of two concentric metal spheres are a and b respectively, and the dielectric constant of the ideal dielectric is   between two metal spheres, the voltage between the inner and outer spheres is U, then the electric displacement vector D on the outer sphere surface (radius b) in the dielectric is
选项：
A:
B:
C:
D:
答案: 【】

3、 问题:The conductor radius of double wire transmission line is  5mm, and the distance between geometric axes is 1m. judge whether the air on the conductor surface be broken down as the voltage applied between conductors is 100kV. The breakdown field intensity of air is 
选项：
A:Yes
B:No
C:Can not be judged
D:Other three answers are all right
答案: 【No】

4、 问题:The flux of electric field intensity  E through a closed surface is equal to zero, which means in the surface
选项：
A:there are more positive charges than negative charges.
B:there are more negative charges than positive charges.
C:there are the same quantity of the positive charges and negative charges.
D:there is no polarized chargeharge.
答案: 【there are the same quantity of the positive charges and negative charges.】

5、 问题:The existence of polarized charge increases the electric field intensity in the medium.
选项：
A:正确
B:错误
答案: 【错误】

Chapter I–D Physical Basis of Electromagnetic Field Exam of Magnetici Field Intenstiy and Magneti

1、 问题:The unit of magnetic induction intensity is 
选项：
A: Webermeter
B:Tesla
C:Ampere/meter
D: Weber/meter
答案: 【Tesla】

2、 问题:An Infinite straight wire with radius a, the current denstiy flowing in it is , find  a the magnetic induction intensity of  ny point with distance b from wire axis ,  b>a outside the wire.
选项：
A:
B:
C:
D:
答案: 【】

3、 问题:Express the value of H in tectangluar components  at P(0,0.2,0) in the field  of a current filament 2.5A  in the  direction  at x=0.2, y= 0.3.
选项：
A:1.989+1.989
B:1.899+1.899
C:1.989-1.989
D:1.899-1.899
答案: 【1.989-1.989】

4、 问题:When the medium is magnetized, the molecular magnetic moment inside the paramagnetic material turns to the opposite direction of the external magnetic field
选项：
A:正确
B:错误
答案: 【错误】

5、 问题:The magnetic field inside the magnetic medium is generated  by both conduction current and polarization current.
选项：
A:正确
B:错误
答案: 【正确】

Chapter I–E Physical Basis of Electromagnetic Field Exam of Maxwell’s Equations

1、 问题:Which descriptions  about Maxwell’s equations is wrong?
选项：
A:Maxwell’s equations can be applied in any medium.
B:The magntic lines of time-varying field is diffenent from that of the static field.
C:Static field equations can be seen as a special case of Maxwell’s equations.
D:The electric lines of time-varying field is diffenent from that of the static field.
答案: 【The magntic lines of time-varying field is diffenent from that of the static field.】

2、 问题:The current between the plates of capacitor with ideal dielectric is :
选项：
A:displacement current
B:conduction current
C:the surface integral  of induced charge density
D:the surface integral  of  free charge density
答案: 【displacement current】

3、 问题:A single turn rectangular coil is coplanar with the long direct current carrying wire, as shown in the figure. The current  is , the coil moves parallel to the right at the speed , and the induced EMF in the coil is
选项：
A:
B:
C:
D:
答案: 【】

4、 问题:Faraday’s law of electromagnetic induction can be used to explained the following devices work ：
选项：
A:Generator
B:Transoformer
C:Electromagnetic furnace
D:Microwave Oven
答案: 【Generator;
Transoformer;
Electromagnetic furnace】

5、 问题:Which of the following statements about the direction of magnetic induction intensity is correct?
选项：
A:is prarallel to the current generating the magnetic field
B:is perpendicular to the current direction that generates the magnetic field