Biju Patnaik University of Technology 2008-4th Sem B.Tech (B Tech) , electromagnetic theory . - Question Paper

BPUT(B Tech) , fourth semester electromagnetic theory ques. paper.

Sixth Semester Examination - 2008 ELECTROMAGNETIC THEORY Full Marks-70

Time: 3 Hours

Answer Question No. 1 which is compulsory and any five from the rest.

The figures in the right-hand margin indicate marks.

1. Explain the following :    2*10

(a)    Can Strokes theorem be applied to closed surfaces ?

(b)    What is the significance of a zero vector?

(c)    What do we mean when we say that an object is charged ?

(d)    Why is the electric field intensity not zero in a steady current carrying current ?

(e)    When can we use Amperes circuital law to determine the magnetic field ?

(f)    What is the significance of div. (B) = 0 ?

(g)    What is meant by depth of penetration ?

(h)    Is it necessary for the fields to satisfy Maxwells equations in order to exist ?

(i)    What is meant by a retarded field ?

(j) What is a uniform linear array ?

(a)    Using the rectangular coordinate system, i verify that (i) div. (curl A) = 0 (ii) curl ^stflr,d" _{(grad f) 6}

(b)    Express the position vector r = x a_x+y a_y + z a_z in the spherical coordinate system.

4

3. (a) Show that the equipotential surfaces for an infinite uniformly charged line are concentric cylinders.    4

(b) A long spherical cloud of radius b has a uniform volume charge distribution of p_v.

Calculate and sketch the potential distribution and also electric field intensity at any point in space using Poissons and Laplaces equation.    6

4.    The conductivity of a homogeneous conducting medium, bounded by 10 cm < r < 20 cm, 30 < 0 < 45 and 30 < <P < 60 is 0.4 S/m. The surface at e = 45 is at a ground potential, and the surface at e = 30 is at 100 V. Using Laplaces equation, determine the resistance of the medium, neglecting the edge effects.    10

5.    (a) What do you mean by magnetic vector

potential ? How is it different from magnetic scalar potential ? Can you derive the Biot-Savart law from the magnetic vector potential ?    5

(b) A straight wire extends from z = -L to z = L and carries a current I. What is the B field in a plane bisecting the wire ? 5

6.    State and explain the conditions of the electromagnetic fields at the interface between

(a)    dielectric - dielectric and

(b)    dielectric - conductor boundaries. 10

7.    (a) Explain the polarization of a wave. What is

the major difference between the elliptically and circularly polarized waves ? 5

(b) In a dielectric medium = 9e₀, n = |i₀( a plane wave with H = 0.2 cos (10⁹t - kx

- k8 z) a_y A/m is incident on an air boundary at z = 0, find (i) the incident E

(ii)    the transmitted and reflected E and

(iii)    k.    5

8.    What is the difference between directive gain and directivity ? Find the directive gain of the Hertzian dipole and compare with that of the half-wave dipole.    10

Sixth Semester Examination - 2008 ELECTROMAGNETIC THEORY Full Marks-70

Time: 3 Hours

Answer Question No. 1 which is compulsory and any five from the rest.

The figures in the right-hand margin indicate marks.

1. Explain the following :    2*10

(a)    Can Strokes theorem be applied to closed surfaces ?

(b)    What is the significance of a zero vector?

(c)    What do we mean when we say that an object is charged ?

(d)    Why is the electric field intensity not zero in a steady current carrying current ?

(e)    When can we use Amperes circuital law to determine the magnetic field ?

(f)    What is the significance of div. (B) = 0 ?

(g)    What is meant by depth of penetration ?

(h)    Is it necessary for the fields to satisfy Maxwells equations in order to exist ?

(i)    What is meant by a retarded field ?

(j) What is a uniform linear array ?

(a)    Using the rectangular coordinate system, i verify that (i) div. (curl A) = 0 (ii) curl ^stflr,d" _{(grad f) 6}

(b)    Express the position vector r = x a_x+y a_y + z a_z in the spherical coordinate system.

4

3. (a) Show that the equipotential surfaces for an infinite uniformly charged line are concentric cylinders.    4

(b) A long spherical cloud of radius b has a uniform volume charge distribution of p_v.

Calculate and sketch the potential distribution and also electric field intensity at any point in space using Poissons and Laplaces equation.    6

4.    The conductivity of a homogeneous conducting medium, bounded by 10 cm < r < 20 cm, 30 < 0 < 45 and 30 < <P < 60 is 0.4 S/m. The surface at e = 45 is at a ground potential, and the surface at e = 30 is at 100 V. Using Laplaces equation, determine the resistance of the medium, neglecting the edge effects.    10

5.    (a) What do you mean by magnetic vector

potential ? How is it different from magnetic scalar potential ? Can you derive the Biot-Savart law from the magnetic vector potential ?    5

(b) A straight wire extends from z = -L to z = L and carries a current I. What is the B field in a plane bisecting the wire ? 5

6.    State and explain the conditions of the electromagnetic fields at the interface between

(a)    dielectric - dielectric and

(b)    dielectric - conductor boundaries. 10

7.    (a) Explain the polarization of a wave. What is

the major difference between the elliptically and circularly polarized waves ? 5

(b) In a dielectric medium = 9e₀, n = |i₀( a plane wave with H = 0.2 cos (10⁹t - kx

- k8 z) a_y A/m is incident on an air boundary at z = 0, find (i) the incident E

(ii)    the transmitted and reflected E and

(iii)    k.    5

8.    What is the difference between directive gain and directivity ? Find the directive gain of the Hertzian dipole and compare with that of the half-wave dipole.    10

Sixth Semester Examination - 2008 ELECTROMAGNETIC THEORY Full Marks-70

Time: 3 Hours

Answer Question No. 1 which is compulsory and any five from the rest.

The figures in the right-hand margin indicate marks.

1. Explain the following :    2*10

(a)    Can Strokes theorem be applied to closed surfaces ?

(b)    What is the significance of a zero vector?

(c)    What do we mean when we say that an object is charged ?

(d)    Why is the electric field intensity not zero in a steady current carrying current ?

(e)    When can we use Amperes circuital law to determine the magnetic field ?

(f)    What is the significance of div. (B) = 0 ?

(g)    What is meant by depth of penetration ?

(h)    Is it necessary for the fields to satisfy Maxwells equations in order to exist ?

(i)    What is meant by a retarded field ?

(j) What is a uniform linear array ?

(a)    Using the rectangular coordinate system, i verify that (i) div. (curl A) = 0 (ii) curl ^stflr,d" _{(grad f) 6}

(b)    Express the position vector r = x a_x+y a_y + z a_z in the spherical coordinate system.

4

3. (a) Show that the equipotential surfaces for an infinite uniformly charged line are concentric cylinders.    4

(b) A long spherical cloud of radius b has a uniform volume charge distribution of p_v.

Calculate and sketch the potential distribution and also electric field intensity at any point in space using Poissons and Laplaces equation.    6

4.    The conductivity of a homogeneous conducting medium, bounded by 10 cm < r < 20 cm, 30 < 0 < 45 and 30 < <P < 60 is 0.4 S/m. The surface at e = 45 is at a ground potential, and the surface at e = 30 is at 100 V. Using Laplaces equation, determine the resistance of the medium, neglecting the edge effects.    10

5.    (a) What do you mean by magnetic vector

potential ? How is it different from magnetic scalar potential ? Can you derive the Biot-Savart law from the magnetic vector potential ?    5

(b) A straight wire extends from z = -L to z = L and carries a current I. What is the B field in a plane bisecting the wire ? 5

6.    State and explain the conditions of the electromagnetic fields at the interface between

(a)    dielectric - dielectric and

(b)    dielectric - conductor boundaries. 10

7.    (a) Explain the polarization of a wave. What is

the major difference between the elliptically and circularly polarized waves ? 5

(b) In a dielectric medium = 9e₀, n = |i₀( a plane wave with H = 0.2 cos (10⁹t - kx

- k8 z) a_y A/m is incident on an air boundary at z = 0, find (i) the incident E

(ii)    the transmitted and reflected E and

(iii)    k.    5

8.    What is the difference between directive gain and directivity ? Find the directive gain of the Hertzian dipole and compare with that of the half-wave dipole.    10

Sixth Semester Examination - 2008 ELECTROMAGNETIC THEORY Full Marks-70

Time: 3 Hours

Answer Question No. 1 which is compulsory and any five from the rest.

The figures in the right-hand margin indicate marks.

1. Explain the following :    2*10

(a)    Can Strokes theorem be applied to closed surfaces ?

(b)    What is the significance of a zero vector?

(c)    What do we mean when we say that an object is charged ?

(d)    Why is the electric field intensity not zero in a steady current carrying current ?

(e)    When can we use Amperes circuital law to determine the magnetic field ?

(f)    What is the significance of div. (B) = 0 ?

(g)    What is meant by depth of penetration ?

(h)    Is it necessary for the fields to satisfy Maxwells equations in order to exist ?

(i)    What is meant by a retarded field ?

(j) What is a uniform linear array ?

(a)    Using the rectangular coordinate system, i verify that (i) div. (curl A) = 0 (ii) curl ^stflr,d" _{(grad f) 6}

(b)    Express the position vector r = x a_x+y a_y + z a_z in the spherical coordinate system.

4

3. (a) Show that the equipotential surfaces for an infinite uniformly charged line are concentric cylinders.    4

(b) A long spherical cloud of radius b has a uniform volume charge distribution of p_v.

Calculate and sketch the potential distribution and also electric field intensity at any point in space using Poissons and Laplaces equation.    6

4.    The conductivity of a homogeneous conducting medium, bounded by 10 cm < r < 20 cm, 30 < 0 < 45 and 30 < <P < 60 is 0.4 S/m. The surface at e = 45 is at a ground potential, and the surface at e = 30 is at 100 V. Using Laplaces equation, determine the resistance of the medium, neglecting the edge effects.    10

5.    (a) What do you mean by magnetic vector

potential ? How is it different from magnetic scalar potential ? Can you derive the Biot-Savart law from the magnetic vector potential ?    5

(b) A straight wire extends from z = -L to z = L and carries a current I. What is the B field in a plane bisecting the wire ? 5

6.    State and explain the conditions of the electromagnetic fields at the interface between

(a)    dielectric - dielectric and

(b)    dielectric - conductor boundaries. 10

7.    (a) Explain the polarization of a wave. What is

the major difference between the elliptically and circularly polarized waves ? 5

(b) In a dielectric medium = 9e₀, n = |i₀( a plane wave with H = 0.2 cos (10⁹t - kx

- k8 z) a_y A/m is incident on an air boundary at z = 0, find (i) the incident E

(ii)    the transmitted and reflected E and

(iii)    k.    5

8.    What is the difference between directive gain and directivity ? Find the directive gain of the Hertzian dipole and compare with that of the half-wave dipole.    10

CPEE 5307    4    -C

Attachment: biju-patnaik-university-of-technology-2008-b-tech-36039-1.pdf

Earning:   Approval pending.