课程名称︰普通物理学甲下
课程性质︰电机系必带
课程教师︰王名儒
开课学院：电资学院
开课系所︰电机工程学系
考试日期（年月日）︰2014/04/17
考试时限（分钟）：10:20 ~ 12:30, 130min
是否需发放奖励金：是
试题 :
1. Two isolated concentric non-conducting spherical shells have radii R1 and
R2, uniformly distributed charges Q1 and Q2, and negligible thickness.
Determine the magnitude of electric field E(r) and the electric potential
V(r), where V is set to zero at infinity.
2. Find the electric energy stored in a cylindrical capacitor of length L and
radii a and b with charge ±Q. Show that the energy density is 0.5ε0*E^2.
3. A 1000W radiant heater is constructed to operate at 110V. What will be the
current in the heater? What is the resistance of the heating coil?
4. The diagrams show three circuits consisting of concentric circular arcs
(either half or quarter circles of radii r, 2r, 3r) and radial lengths. The
circuits carry the same current I, running clockwise in the upper half
circle. Find the magnetic fields at C for each case.
http://ppt.cc/vuLQ
5. The current density J inside a long , solid , cylindrical wire of radius a,
is in the direction of the central axis, and its magnitude varies linearly
with radial distance r from the axis according to J=J0*r/a. Determine the
magnitude of the magnetic field as a function of r.
6. Draw a simple schematic diagram of the mass spectrometer which can be used
to determine the mass of an ion. You need to describe the operation
principle and write down related formula.
7. If we suddenly introduce an emf ε into a single-loop circuit containing a
resistor R and a capacitor C, find out the current in this loop as a
function of time.
8. Using a L-C network to model an infinitely long coaxial cable, show that
the termination resistor of the coaxial cable is equal to √L/C, where L(C)
stands for the inductance (capacitance) per unit length of the coaxial
cable. You should assume that the resistance is negligibly small and L(C)
is also a small number.
9. Write down the Maxwell's equations and comment on the contribution made by
Maxwell.
10.A light wave polarized parallel to a y axis is traveling in the negative
direction of a z axis. The rms value of the electric field is 50 V/m, and
the wavelength is 400 nm. Write down the functional form of the magnetic
field component of the wave. What is the pointing vector of this wave?