Bài giảng Electromagnetic Fields - Chapter 3 - Trần Quang Việt
D3.6. In a small region around the origin, the current density due to
flow of charges is given by :
Find the time rate of increase of the charge
density at each of the following points: (a) (0.02, 0.01, 0.01); (b)
(0,02, -0.01, -0.01); and (c) (-0.02, -0.01, 0.01)
D3.19.The magnetic field associated with a uniform plane wave
propagating in the +z-direction in free space is given by:
Find the following : (a) the instantaneous power flow across a surface
of area 1m2 in z=0 plane at t=0; (b) the instantaneous power flow
across a surface of area 1m2 in z=0 plane at t=(1/8) µs; and (c) the
time-average power flow across a surface of area 1m2 in z=0 plane.
flow of charges is given by :
Find the time rate of increase of the charge
density at each of the following points: (a) (0.02, 0.01, 0.01); (b)
(0,02, -0.01, -0.01); and (c) (-0.02, -0.01, 0.01)
D3.19.The magnetic field associated with a uniform plane wave
propagating in the +z-direction in free space is given by:
Find the following : (a) the instantaneous power flow across a surface
of area 1m2 in z=0 plane at t=0; (b) the instantaneous power flow
across a surface of area 1m2 in z=0 plane at t=(1/8) µs; and (c) the
time-average power flow across a surface of area 1m2 in z=0 plane.
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- Electromagnetic Fields – Prob – ch_3 P3.37. The electric and magnetic fields in a coaxial cable, an arrangement of two coaxial perfectly conducting cylinders of radius a and b (>a), are given by: V0 E= cosω ( t − z µ ε )ar for a << r b rln(b/ a) 0 0 I0 H= cosω ( t − z µ ε )aφ for a << r b 2π r 0 0 where V 0 and I 0 are constants and the axis of the cylinders is the z- axis. (a) Find the instantaneous and time-average Poyting vectors assosiated with the fields. (b) Find the time-average power flow along the coaxial cable. Tr ần Quang Vi ệt – BMCS – Khoa Điện – ĐHBK Tp.HCM 3
