[試題] 97下 王建萬 普物甲下 期末考
課程名稱︰普通物理甲下
課程性質︰必修
課程教師︰王建萬
開課學院：
開課系所︰生工系
考試日期（年月日）︰2009/6/19
考試時限（分鐘）：110分鐘
是否需發放獎勵金：要
（如未明確表示，則不予發放）
試題 :
1. A plane electromagnetic wave, with wavelength 2.0m, travels in vacuum in the
positive direction of an x axis. The electric field, of amplitude 500 V/m,
oscillates parallel to the y axis. What are the (a) frequency, and (b) angular
frequency, and (c) angular wave number of the wave? (d) What is the amplitude
of the magnetic field component? (e) Parallel to which axis does the magnetic
field oscillate? (f) What is the time-averaged rate of energy flow in watts
per square meter associated with the wave? The wave uniformly illuminates a
surface of area 4.0m^2. If the surface totally absorbs the wave, what are (g)
the rate at which momentum is transferred to the surface and (f) the radiation
pressure on the surface? (16%)
2.An ac generateor emf ε=εm*sin(Wd*t-π/4)，where εm = 20.0V and
Wd = 500 rad/s.The current produced in a connect circuit is
i(t) = I*sin(Wd*t-3π/4)，where I = 720 mA.At what time after t = 0 does
(a)the generate emf first reach a maximum and (b)the current first reach
a maximum ? (c)The circuit contains a single element other than the
generate.Is it a capacitor，an inductor，or a resistor ? Justify your answer
. (d)What is the value of the capacitance，inductance，or resistance，as the
case may be ? (10%)
3.In a double-slit experiment, the electric fields of the waves arriving
at point P on the screen are given by E1=E0Sin(kx1-wt),E2=E0Sin(kx2-wt),
What are (a) the path difference,(b)the phase difference, and(c) the wave
number difference of the two waves at P? What is the relation between d
(slits separation),λ(wavelength), and θ if P shows (d) a bright fringe,(e)
a dark fringe? see Fig.1 (11%)
4.In Fig.2，a capacitor with circular plates of radius R = 30.0cm is connected
to a source of emf ε = εm*sinwt，where εm = 300V and w = 160 rad/s.The
maximum value of the displacement current id=10.0μA.Neglect fringing of the
electric field at the edges of the plates.(a)Whst is the maximum value of
the current i in the circuit ? (b)What is the maximum value of dΦ/dt，where
Φ is the electric flux through the region between the plates ? (c)What is
the separation d between the plates ? (d)Find the maximum value of the
magnitude of B between the plates at a distance r = 20.0am from the center ?
(10%)
5.Fig.3 show a cross section across a diameter of a long cylindrical conductor
of radius a = 4.00cm carrying uniform current 300 A.What is the magnitude of
the current's magnetic field at radial distance(a)0，(b)2.00cm，(c)4.00cm
(wire's surface)，and(d)6.00cm ? (10%)
6.The full width at half-maximum (FWHM) of a central diffraction maximum is
defined as the angle between the two points in the pattern where the
intensity is one-half that at the center of the pattern.(Fig.4)(a)Show that
the intensity drops to one-half the maximum value when (sinα)^2 = α^2/2.
(b)Verify that α = 1.39 rad is a solution to the transcendental equation of
(a).(c)Show that the FWHM is Δθ= 2sin-1(0.443λ/a)，where a is the slit
width.Calculate the FWHM of the central maximum for slit width(d)1.50λ，
(e)2.50λ，and(f)6.00λ (12%)
7.Fig.5 show a rod of length L = 16.0cm that is force to move at constant
speed v = 10.00m/s along horizontal rails.The rod，rails，and connecting
strip at right form a conducting loop.The rod has a resistance 0.600Ω；the
rest of the loop has negligible restance A current i = 160a through the long
straight wire at distance a = 12.0mm from the loop sets up a (nonuniform)
magnetic field through the loop.Find the (a)emf and (b)current induced in the
loop.(c)At what rate is thermal energy generated in the rod ? (d)What is the
magnitude of the force that must applied to the rod to make it move at
constant speed ? (e)At what rate does this force do work on the rod ? (11%)
8.In Fig.6, a wire loop of dimensions L=60.0cm and W=40.0cm lies in a
magnetic field B. What are the (a) magnitude ε and (b) direction (clockwise
or counterclockwise - or "none" if ε=0) of the emf induced in the loop if
B=(6.00×10^-2T/m)yk? What are (c) ε and (d) the direction if
B=(8.00×10^-2T/s)tk? What are (e) ε and (f) the direction if
B=(12.00×10^-2T/m‧s)tk? What are (g) ε and (h) the direction if
B=(5.00×10^-2T/m‧s)xtj? What are (i) ε and (j) the direction if
B=(8.00×10^-2T/m‧s)yti? (20%)
Halliday 8th Fundamentals of PHYSICS Extended
1. 33.25
2. 31.33
3.
4. 32.29
5. 29.45
6. 36.17
7. 30.35
8. 30.18
Figure 1 35-10
Figure 2 32-26
Figure 3 29-70
Figure 4 36-8(b)
Figure 5 30-59
Figure 6 30-49
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