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Unformatted text preview: The Hashemite University Final Exam Electrical Engineering Department Electromagnetic I
second Sem. 06/07 Faculty of Engineering Instructors: Dr. Omar Saraereh Time: 2 hour Q1: Complete the following statements: (35 marks) 1) The angle at which line x = y = 2z intersects the ellipsoid x2 + y2 + 2z2 = 10 is ………………….....................
∧ (Note: ∇ A = x ∂A ∧ ∂A ∧ ∂A
+y
+z
).
∂x
∂y
∂z 2) The curl of a vector field is a measure of the ………………… of the vector field per unit area ∆s, with the
orientation of ∆s chosen such that the …………………………..
→ ∧ ∧ → 3) If G ( r ) = 10 exp(−2 z )(r r + z ) , the flux of G out of the entire surface of the cylinder r = l , 0 < z < 1 is
…………………………..
4) A spherical shell centered at the origin extends between R = 2 cm and R = 3 cm. If the volume charge density
is given by 3R × 104 (C/m3), then the total charge contained in the shell is ………………………………………
→ ∧ 5) If J = y xz (A/m 2 ) , the current I flowing through a square with corners at (0, 0, 0), (2, 0, 0), (2, 0, 2) and
(0, 0, 2) is ………………………
6) The normal component of the electric field density changes abruptly at a charged boundary between two
different media, and the amount of change is equal to the …………..
7) The value of capacitance obtained for any specific capacitor configuration is always independent of ………..
8) Three point charges, each with q = 3 nC, are located at the corners of a triangle in the x–y plane, with one corner at the origin, another at (2 cm,0,0), and the third at (0,2 cm,0). The force acting on the
charge located at the origin is …………………….
9) The total magnetic force on any closed current loop in a ……………………………… is zero.
10) A long, EastWest oriented power cable carrying an unknown current I is at a height of 8 m above the
earth’s surface. If the magnetic flux density recorded by a magneticfield meter placed at the surface is 15 μT
when the current is flowing through the cable and 20 μT when the current is zero. The magnitude of I is ……….
11) The conducting triangular loop in Figure. 1 carries a current of 10A.
The magnetic field at (0,0,5) due to side 1 of the loop is
………………………..
12) The plane boundary defined by z = 0 separates air from a block of iron.
→ ∧ ∧ ∧ → If B1 = 4 x − 6 y + 8 z in air (z ≥ 0), The B2 in iron (z ≤ 0) is ……………………….., (given that μ = 5000 μ 0 for iron). 13) Gauss's law for magnetism states that …………………………………..
Figure. 1
14) …………………. States that the line integral of the magnetic field around a closed path is equal to the
current traversing the surface bounded by that path www.Husni.net Q2: Obtain an expression for the selfinductance per unit length for the parallel wire transmission line of Figure.
2 in terms of a, d, and μ, where a is the radius of the wires, d is the axistoaxis distance between the wires, and
μ is the permeability of the medium in which they reside.
(15 marks) Figure. 2 www.Husni.net ...
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 Spring '12
 OmarSarayra
 Electromagnet

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