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# JNTUH ETTL MODEL PAPERS AND IMPORTANT QUESTIONS

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DEPARTMENT OF
ELECTRONICS AND COMMUNICATION ENGINEERING B.Tech II year – II Semester
Examinations, Model Paper-1 ELECTROMAGNETIC WAVES AND TRANSMISSION LINES
 Time: 3 hours Max. Marks: 75 PART- A (25 Marks) 1.   a. State and Express the Coulomb‟s Law. (2M) b. Derive the Possion‟s and Laplace Equations for electrostaticfield. (3M) c. State and Express the Biot-Savart‟s Law. (2M) d. Writedown the Maxwell‟s Equations in word statement. (3M) e. Define the Uniform Plane wave. (2M) f .Define the Surface Impedance. (3M) g.Define the characterstic impedance. (2 M) h. Define the phase velocity. (3 M) i. Define the Reflection Coefficient (2 M) j. Explain the losses in transmission Line. (3 M)
PART-B (5*10=50
Marks)
2.    a. State and Prove Gauss‟s Law.
b.Let = 400Sinθ/(r2+4) ar A/m2.
Find the total current flowing through that portion of the
spherical
surface r=0.8 bounded by 0.1 <θ<0.3π ,0< <2π.
OR
3.a. Show That = ρ b.Given The Flux density D=16/r cos(2θ) c/m2,
Find the total charge with in the region 1<r<2m, 1<
θ<2rad,1< <2π
4.
a.State The Law required to calculate magnetic flux density or magentic field
intensity for a
given
current or current distribution and derive the expression for the same.
b.Derive the conditions at boundary
surface of Dielectric-Dielectric interface?
OR
5.a. Define and Explain Ampere‟s circuit Law.
b.State Maxwell‟s Equations in Differential and Integral form with clear statement
6.
a. Derive the equation
for uniform plane wave in terms of H.
b.  A
100MHz uniform plane wave Propagates in a lossless medium for which r=5
and µ
r=1
find
vp,β,λ,Es,Hs.
OR
7.     a. State and Prove the Pointing Theorem
b. Write short Notes on
i)Surface impedance ii) Brewster Angle
8.
a. Derive The Expression
for Transmission Line Equation. b.
Given R = 10.4
Ω/mt
L
= 0.00367 H/mt
G
= 0.8×10
-4
mhos/mt
C
= 0.00835 µF/mt.
Calculate
Z
0
and at 1.0
KHz
.
OR
9.Derive the expression
for α and β in terms of primary constants of a line
10.a) Establish the relations for Zsc  and Zoc  of rf lines and sketch their variation with
βl
b) A 60ohm lossless line
is 30m long and is terminated with a load of 75+j50ohms at 3MHz
find its
reflection coefficient,VSWR,if the line velocity is 60% of the velocity of
light
OR
11. a) Explain the principle of single
stub matching. b)Calculate the skin depth for the following conditions.
i) Copper f=1010Hz,µ=µ0,
σ=5.8×10
7s/m

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DEPARTMENT OF
ELECTRONICS AND COMMUNICATION ENGINEERING B.Tech II year – II Semester
Examinations, Model Paper-2 ELECTROMAGNETIC WAVES AND TRANSMISSION LINES
 Time: 3 hours Max. Marks: 75 PART- A (25 Marks) 1. a. Define Electric Potential and Ploarization (2M) b. Define Capacitance? Explain different types of capacitances (3M) c. State and Express the Amperes circuit Law (2M) d. Define the boundary condition? Give the relations for electric field (3M) e. Define Brewster Angle (2M) f. Define Polarization? Explain different types of polarization (3M) g. Define the Propagation constant in terms of primary constants (2M) h. Define the group velocity (3M) i. Define the stub? (2M) j. Write down the Applications of Smith chart (3M) PART-B (5*10=50 Marks) 2.a. State and prove the coulomb‟s law ?
b.  Find
the force on a charge of -100mC located at P(2,0,5) in free space due to
another charge 300µC located at Q(1,2,3).
OR
3. a. State and
Prove  Laplace‟s and  Poissson‟s Equation Starting from
Gauss‟s  Law
b. The potential
field V=2x
2yz-y3z
exists in a dielectric medium having ε=2ε
0  calculate
.                the
total charge within the unit cube 0<x<1m,0<y<1,0<z<1m.
4.a. Define Ampere‟s Circuit Law in point
and integral forms for Static fields.
b.
Establish the fields in the different regions of a coaxial cable carrying a
current I, and sketch their variation with radial distance.
OR
5. a.State and Prove Boundary condition between Dielectric-Dielectric
b. A Potential field is given by V=15(x2-y2).The
point p(4,-2,1) lies on the boundary of the conductor and free space At P,
obtain the magnitudes of i) V ii) E iii) E
N
iv) E
tan
v)D vi) ρ
s
6.  a. Derive The
attenuation and phase constant in conducting medium
b. At 50MHz, a lossy dielectric
material is characterized by ε=3.6ε
0, µ=2.1µ0 and σ=0.08S/m. If
Es=6e
-ϒxazV/m, compute i) ϒ ii) λ iii) u
iv)η v) H
S
OR
7. a.Derive Expression for reflection and transmission coefficients of an EM wave
when it is incident normally on a dielectric
b. A perpendicularly polarized wave is
incident at an angle of ө
i=15degrees.
It is propagating from medium1 to medium2 .medium 1 is defined by ε
r1=8.5,μr1=1,σ1=0
and medium 2 is free space if E
i=1mv/m,
determine E
r,
H
i,
H
r
8. a. Derive The Condition
for Distrotionless Transmission Line
b. Measurements on a Transmission Line
of length 120Km were made at frequency of 6000Hz.If Z
OC=520(-30deg)
and Z
SC=640(43deg)
find Z
o
and P.
OR
9.  a. Derive The Basic
Transmission Line Equation
b.The propagation constant of a lossy transmission line is 1+j2 m-1 and its
characteristic impedance is
20+j0Ω
at ω= 1rad/s. Find R,C,L,G for the Line.
10.a.Derive the relation between reflection coefficient and characteristic impedance
b. Write short notes on smith chart
OR
11.A transmission line of
length 0.40λ ? has a characteristic impedance of 100Ω and is Terminated in a
load impedance of 200 + j180ω. Find the
(a)  Voltage
reflection coefficient
(b)  Voltage
standing wave ratio
(c)  Input
impedance of the line.

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DEPARTMENT OF
ELECTRONICS AND COMMUNICATION ENGINEERING B.Tech II year – II Semester
Examinations, Model Paper-3 ELECTROMAGNETIC WAVES AND TRANSMISSION LINES
 Time: 3 hours Max. Marks: 75 PART- A (25 Marks) 1.a.Define Electric field and Electric flux Density (2M) b. Define Electric dipole? Differentiate between polar and non polar dielectrics (3M) c. State and Express the Stokes Theorem (2M) d. Write down the Maxwell‟s equations in free space condition (3M) e. Define Skin depth or Depth of penetration (2M) f. State and Express the Poynting theorem (3M) g. Write down the Distortionless Line (2M) h. Define Transmission line? Explain different types of Transmission lines (3M) i. Define the voltage Standing Wave Ratio (2M) j. Difference between the single stub matching and double stub matching (3M) PART-B (5*10=50 Marks) 2. a. Define Line charge Density? Derive the infinite line Electric field E=ρL/2 aρ b. Find E at(2,0,2) if a line charge of 10PC/m lies along the y-axis OR 3.  a.
Define Capacitance and obtain the parallel plate capacitance
b.  A parallel plate capacitance has 500mm side plates of square shape separated by
10mm distance A sulphur
slab of 6mm plates with ε
r=4
kept is on the lower plate find the capacitance of the set up If a voltage of
100V is applied across the
capacitor calculate the voltages at both
the regions of the capacitor between the plates.
4 .a. Derive an expression for magnetic
field strength,H,due to a finite filamentary conductor carrying a current I and
placed along Z-axis at a point „P‟ on Y-axis. Hence deduce the magnetic field
sgtrength for the length of the conductor extending -∞ to +∞.
b. State and
Prove Biot-Savart‟s Law.
OR
5.a.What is the inconsistency of Ampere‟s Law
b.A certain material has σ=0 and εr=1 if H=4sin(106t-0.01z) A/m.
Make use of
Maxwell‟s equations to find µr.
6. a. Show that E and H are
perpendicular to each other inphase and the ratio of their Magnitudes is a
constant for a uniform plane wave.
b.
A uniform plane wave at
a frequency of 1GHz is travelling in a large block of teflon
εr=2.1,µr=1
andσ=0. Determine ϒ,η,β,λ.
OR
7.  a.Define Polyting’s theorem and Polyting Vector.
b.  A Sinsoidally varying EM wave in a medium of εr=1
µ
r=1
is transmitting power at a density 1.2watts/m
2
.Find the maximum values of E and H fields.
8.Explain the
conditions which are used for minimum attenuation in transmission lines
OR
10.a. Derive the expression for the
input impedance of a transmission line of length L. b. List out the
applications of transmission lines
OR
11
.Describe the construction of smith chart and give its applications.

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DEPARTMENT OF
ELECTRONICS AND COMMUNICATION ENGINEERING B.Tech II year – II Semester
Examinations, Model Paper-4 ELECTROMAGNETIC WAVES AND TRANSMISSION LINES
 Time: 3 hours Max. Marks: 75 PART- A (25 Marks) 1.a. State and Express the Divergence theorem (2M) b. A charge of 10PC is at rest in free space.Find the potential at a point, A 10cm away from the charge. (3M) c. A magnetic field, H=3ax+2ay,A/m exists at a point in free space, what is the magnetic flux density at the point (2M) d. Explain the different types of medium (3M) e. Define the Good Conductor (2M) f.Differences between intrinisic impedance and surface impedance (3M) g. Define the characterstic impedance in terms of the open circuit and short circuit impedance (2M) h. Define and Explain the infinite Line (3M) i. Define the smith chart (2M) j. Write downthe relation between reflection coefficient and voltage standing wave ratio (3M) PART-B (5*10=50 Marks)
2.a .State coulomb‟s and derive the
expression for coulomb‟s law to calculate the magnitude of The force between
two charges
b.Prove the poisson‟s equation for Electrostatic field
OR
3.a.Distinguish between the conduction
and convention currents. Establish the current Continuity equation and hence
calculate the relaxation time for brass material, having Conductivity of 1.1×10
7mho/m
at 10MHz.
b.Find the capacitance of a 50cm.long
coaxial cable, having conductors of 4cm and 2cm diameters, separated by a
medium of a relative permittivity 2.56.
4.a.Define Inductance?  Derive the toroid inductance
b.A toroid has air core and has a
cross-sectional area of 10mm
2.It
has 1000turns and its mean radius is 10mm.Find its Inductance
OR
5.a.Obtain the integral form of Maxwell‟s equation from Amperes circuit law in the
generalized form
b.  In a medium of µr=2,
find E,B and displacement current density if H=25sin(2×10
8t+6x) mA/m
6.  a.For good dielectrics derive the expressions for α,β,ϒ,η
b. A plane wavetravelling in a medium of εr=1,µr=1
has an electric field intensity of v/m.Determine the energy density in the
magnetic field and also the total energy density.
OR
7.a Derive Expression for
reflection and transmission coefficients of an EM wave when it is incident

normally
on a dielectric.
b.A perpendicularly polarized wave is incident at an angle of өi=15degrees.
It is is free propagating from medium1 to medium2 .medium 1 is defined by
ε
r1=8.5,μr1=1,σ1=0 and medium2 space if Ei=1mv/m, determine Er, Hi,
H
r.
8.a.Derive the attenuation constant and
phase constant in terms of primary constants b.Explain different types of
loading for transmission lines.
OR
9.a.Derive the characteristic impedanceof a transmission line in terms of its line constants
b.At 8MHz thecharacteristic impedance of a transmission line as 40-j2ohms and the
propagation
constant 0.01+j0.18 per meter.Find the primary constant.
10.Explain the principal of single stub matching
OR
11.  a.Derive the relation between reflection coefficient and characteristic impedance
b. write short notes on smith chart.

jntumaterials.com
DEPARTMENT OF
ELECTRONICS AND COMMUNICATION ENGINEERING B.Tech II year – II Semester
Examinations, Model Paper-5 ELECTROMAGNETIC WAVES AND TRANSMISSION LINES
Time:
3 hours
Max.
Marks: 75
 PART- A (25 Marks) 1.a.The force F=2ax+ay+az N, is acting on a charge of 10C, find the electric field Intensity,its magnitude and direction. (2M) b.The current density J=1/r2(cosӨar+sinӨ   ),A/m2, find the current passing through a sphere radius of 1m (3M) c.Given magnetic flux density,B=ρ   ,find the total flux crossing the surface 1<ρ<2m and 0
PART-B (5*10=50
Marks)
2.a.State and Explain Coulomb‟s law.
b.Three point charges Q1=0.5nC,Q2=0.4nC, Q3=-0.6Nc are located in free space
at(0,0),(3,0)and(0,4)respectively.Determine the potential,electricfield
intensity and flux density at (3,4).
OR
3.  a.
Determine the amount of work necessary to assemble three point charges Q1,
Q2,Q3 in an empty space. Extend your result to n-point charges.
b.  Show that = ρ .
4.
a. State and Prove the Ampere‟s Force Law.
b.A toroidal ring has 200turns. The outer diameter of the ring is 15cm with the
inner diameter of 12cm.Find the flux density if the current is 8A.
5.
a. State and explain boundary conditions between two dielectric media.
b.  A circular loop conductor having radius of 0.2m is placed in XY plane. The loop
consists of a resistance of 10ohms. If the Magnetic field is B=Sin10
4t
Tesla, find the current flowing in the loop.
6. a.Discuss the significance of pointing theorem and derive the equation for pointing Vector.
b.A vertically polarized uniform plane wave is incident at an angle of 450
from air on a dielectric slab of ϵ
r=4,µr=1 and σ=0.the incident field strength is 100mV/m at 10MHz.Calculate the power transmitted to the dielectric slab Find the angle of incidence for which angle of reflection is zero.
OR
7.a.Derive the equation for uniform plane wave in free space condition.
b.The electric field in free space is given by E=50cos(108t+βx)ayV/m.Find
the direction of wave propagation.Calculate β and time it takes to travel a
distance of λ/2
8. Derive the equation for input
impedance of the Eighth-Wave(λ/8) line? Explain Its significance
OR
9.
Write Short notes on
i)  Smith
Chart
ii)Single stub matching
10.a.Derive an expression for thepropagation constant and characteristic impedance of Transmission line withR,L,C,G.
b. A telephone line has
R=30Ω/km, L=100Mh/km, G=0,C=20µF/km. At f=1KHz,obtain i) Z
0
ii) propagation constant iii ) phase velocity
OR
11.a. Derive an expression for the input impedance of a lossless line of length „l‟
in
Terms of  Z0,  β,Zand l when terminated by a Zload.
b. A lossless transmission line length
„l‟ with Z
0=50
is terminated by a load of Z
L=50+j50.Determine
the reflection coefficient “R
r
and the standing wave
Ratio.
.

Tags: Electromagnetic Theory and Transmission Lines Important Questions JNTUH R13