Đề thi cơ sở điện từ trường 1

Đề thi cơ sở điện từĐề thi cơ sở điện từĐề thi cơ sở điện từĐề thi cơ sở điện từĐề thi cơ sở điện từĐẠI HỌC QUỐC GIA TP Stu ID Stu Fullname Page 11 Lecturer (Date) Approved by (Date) (Signature Fullname) Dr Vo Que Son (Signature, Position Fullname) (The above part must be hidden when copying fo.

Stu.ID: Stu Fullname: Page 1/1

(Signature & Fullname)

Dr Vo Que Son

(Signature, Position & Fullname)

(The above part must be hidden when copying for exam)

Problem 1 (L.O.1) (3 marks): A charge density in a one-dimension device is given by:

3

v

z

C m a



If E=0 at z=0, and V=0 at z=a, find V and E?

Problem 2 (L.O.2) (4 marks): A uniform plane wave propagates from region 1 (z<0) to region 2 (z>0)

Given the conditions:

• The electric component of the wave in region 1:

1

( , ) z t = 5 e−zcos(2 x10  t −  z ) y (V/m)

• Characteristic of region 1: σ1= 10-6(S/m), ε1= 80ε0(F/m), μ1= μ0(H/m),

• Characteristic of region 2: σ2= 10-4(S/m), ε2= 5ε0(F/m), μ2= μ0(H/m)

Find:

a) The reflected electric component in region 1?

b) The transmitted magnetic component in region 2?

c) The distance d (m) where the phase of the transmitted magnetic component in region 2 is changed

by 10π (rad)?

d) The attenuation (in Decibel) at the distance d in question c)?

Problem 3 (L.O.3) (3 marks): In free space (z≤0) a plane wave with:

8 ( , ) 10 cos(10 z t = t −  z ) x (V/m)

is normally incident on a perfect dielectric with ε = ε0and μ=4μ0in the region z≥0

a) Determine phase constant , reflection coefficient and transmission coefficient?

b) Find the reflected and transmitted waves of the magnetic component H(z,t)?

c) Find the time-dependent Poynting vector of reflected electromagnetic waves?

END

-UNIVERSITY OF TECHNOLOGY - VNUHCM

FACULTY OF EEE

Course title Introduction to EM Fields

Notes: - Hard-copy reference materials are allowed Digital reference materials are prohibited.