Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 5th Sem Old 151002 Engineering Electromagnetics Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (OLD) EXAMINATION ? WINTER 2018
Subject Code:151002 Date: 16/11/2018
Subject Name: Engineering Electromagnetics
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Explain the concept of dot product and vector product with the help of proper
equations and vector diagrams.
07
(b) State Coulomb?s law. Derive the expression for following:
i. Scalar & Vector form of Coulomb?s law,
ii. Electric field intensity.
07
Q.2 (a) What do you mean by boundary conditions? Derive the boundary conditions at
the interface between two dielectric materials with permittivities ?1 and ?2.
07
(b) Write down point and integral forms of all four Maxwell?s equations for steady
& time-varying electro-magnetic fields.
07
OR
(b) An infinitely long coaxial cable is carrying current I by the inner conductor of
radius ?a? and ?I by the outer conductor of radii ?b? and ?c?, where c>b. Derive
the expressions for H at (i) ? < a, (ii) a < ? < b, (iii) b < ? < c, (iv) ? > c.
07
Q.3 (a) Using del operator, explain the following in brief:
i. Gradient of a scalar
ii. Curl of a vector
07
(b) Write a detailed note on the divergence & its physical interpretation. 07
OR
Q.3 (a) Derive the expression for the following:
i. The divergence theorem
ii. Stoke?s theorem
07
(b) Illustrate the concept of skin depth and skin effect in good conductors. 07
Q.4 (a) Derive
i. Maxwell?s 1
st
equation for electrostatics
ii. Maxwell?s 3
rd
equation for electrostatics.
07
(b) Given the potential field V=2x
2
y - 5z, and a point P(-4, 3, 6), find following at
point P : the potential V, the electric field intensity E, the direction of E, the
electric flux density D, and the volume charge density ?v.
07
OR
Q.4 (a) Derive
i. Lorentz force equation
ii. Point form of Ohm?s law.
07
(b) Three infinite uniform sheets of charges are located in the free space as follows:
3 nC/m
2
at z = - 4, 6 nC/m
2
at z = 1, and -8 nC/m
2
at z = 4. Determine E at the
point P(2, 5, -5) & Q(4, 2, -3).
07
Q.5 (a) A current filament carrying 15 A in the az direction lies along the entire z axis.
Find H in rectangular coordinates at: (i) PA(20
1/2
, 0, 4).
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (OLD) EXAMINATION ? WINTER 2018
Subject Code:151002 Date: 16/11/2018
Subject Name: Engineering Electromagnetics
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Explain the concept of dot product and vector product with the help of proper
equations and vector diagrams.
07
(b) State Coulomb?s law. Derive the expression for following:
i. Scalar & Vector form of Coulomb?s law,
ii. Electric field intensity.
07
Q.2 (a) What do you mean by boundary conditions? Derive the boundary conditions at
the interface between two dielectric materials with permittivities ?1 and ?2.
07
(b) Write down point and integral forms of all four Maxwell?s equations for steady
& time-varying electro-magnetic fields.
07
OR
(b) An infinitely long coaxial cable is carrying current I by the inner conductor of
radius ?a? and ?I by the outer conductor of radii ?b? and ?c?, where c>b. Derive
the expressions for H at (i) ? < a, (ii) a < ? < b, (iii) b < ? < c, (iv) ? > c.
07
Q.3 (a) Using del operator, explain the following in brief:
i. Gradient of a scalar
ii. Curl of a vector
07
(b) Write a detailed note on the divergence & its physical interpretation. 07
OR
Q.3 (a) Derive the expression for the following:
i. The divergence theorem
ii. Stoke?s theorem
07
(b) Illustrate the concept of skin depth and skin effect in good conductors. 07
Q.4 (a) Derive
i. Maxwell?s 1
st
equation for electrostatics
ii. Maxwell?s 3
rd
equation for electrostatics.
07
(b) Given the potential field V=2x
2
y - 5z, and a point P(-4, 3, 6), find following at
point P : the potential V, the electric field intensity E, the direction of E, the
electric flux density D, and the volume charge density ?v.
07
OR
Q.4 (a) Derive
i. Lorentz force equation
ii. Point form of Ohm?s law.
07
(b) Three infinite uniform sheets of charges are located in the free space as follows:
3 nC/m
2
at z = - 4, 6 nC/m
2
at z = 1, and -8 nC/m
2
at z = 4. Determine E at the
point P(2, 5, -5) & Q(4, 2, -3).
07
Q.5 (a) A current filament carrying 15 A in the az direction lies along the entire z axis.
Find H in rectangular coordinates at: (i) PA(20
1/2
, 0, 4).
07
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2
(b) Find the magnitude of current density in a sample of silver for which ? = 6.17 ?
10
7
S/m and ?e = 0.0056 m
2
/V?s if: (a) the drift velocity is 1.5 ?m/s; (b) the
electric field intensity is 1 mV/m; (c) the sample is a cube 2.5 mm on a side
having a voltage of 0.4 mV between opposite faces; (d) the sample is a cube 2.5
mm on a side carrying a total current of 0.5 A.
07
OR
Q.5 (a) Determine an expression for the volume charge density associated with each of
the following D fields:
(a) D = 4xy/z ax + 2x
2
/z ay ? 2x
2
y/z
2
az;
(b) D = z sin ? a? + z cos ? a? + ? sin ? az;
07
(b) A slab of dielectric material has a relative dielectric constant of 3.8 and contains
a uniform electric flux density of 8 nC/m
2
. If the material is lossless, find: (a) E;
(b) P; (c) the average number of dipoles per cubic meter if the average dipole
moment is 10
-29
C?m.
07
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This post was last modified on 20 February 2020