PARISUTHAM INSTITUTE OF TECHNOLOGY AND SCIENCE
Department of ECE
AY 2015-16
III Year /V Sem.
QUIZ 1
EC6503 TRANSMISSION LINES AND WAVEGUIDES
1. Which of the following shows the real part of the propagation constant?
(A) Variation of voltage and current on basic unit.
(B) Variation of phase shift/position of voltage.
(C) Reduction in voltage, current values of signal amplitude.
(D) Reduction of only voltage amplitude.
ANS: C
2. What is the purpose of an Attenuator?
(A)To increase signal strength.
(C) To decrease reflections.
(B) To provide impedance matching.
(D) To decrease value of signal strength.
ANS: D
3. Which of the following is correct when the transmission line is terminated by a characteristic
Impedance?
(A) There is no reflection of the incident wave.
(B) The reflection is maximum due to termination.
(C) There are a large number of maximum and minimum on the line.
(D) The incident current is zero for any applied signal.
ANS: A
4. What type of distortion arises when the waves are not attenuated equally?
(A) Delay distortion (B) Phase distortion
(C) Frequency distortion (D) All the above
Ans: C
5. Which of the following factor does not depend on frequency?
(A) Primary constants
(B) Velocity
(C) Wavelength
(D)Secondary constants
ANS: A
6. Which of the following defines the condition for a line becomes distortion less?
(A) It is properly matched
(B) It is terminated into Zo (C) LG = CR
(D) LR = GC
ANS: C
7. Find the value of reflection co efficient if the line has Zo = 300Ω and ZL = 150Ω?
(A) 1
(B) 0.5
(C) 0.3
(D) ∞
ANS: C
8. What is the status of the characteristic impedance of a distortion less line?
(A) Real
(B) Inductive
(C) Capacitive
(D) Complex
ANS: A
9. How a transmission line works?
(A) Attenuator
(B) LPF
(C) HPF
(D) Neither of the above
ANS: B
10. At what frequency attenuation is more in open line transmission systems?
(A) lower frequencies
(B) medium frequencies
(C) higher frequencies
(D) remains constant
ANS:C
11.What is the velocity of propagation in a lossless transmission line?
(A) √𝑳/𝑪
(B) √𝑪/𝑳
(C) √𝑳𝑪 (D) 𝟏/√𝑳𝑪
ANS:D
12. Find which of the given ratio defines voltage reflection coefficient?
A. Incident wave to reflected wave
B. Reflected wave to incident wave
C. Incident wave to absorbed wave
D. Absorbed wave to incident wave
ANS:B
13. Which one of the following conditions will not guarantee a distortion less
Transmission Line?
(A) R=0, G=0
(B) LG=RC
(C) R >>ωL, G >>ωC
(D) R <<ωL, G <<ωC
ANS: C
14. Which of the following statement is correct, when the characteristic impedance of the line is
equal to the load impedance?
(A) all the energy will pass to the earth
(B) all the energy will be lost in transmission losses
(C) the system will resonate badly
(D) all the energy sent will be absorbed by the load.
ANS:D
15. Which of the following condition is suitable for a properly terminated line?
(A) ZR=ZO
(B) Z/R > ZO
(C) ZR < ZO
(D) ZR =Z0 = 0.
ANS:D
16. Which of the following factor produces the distortion in transmission line?
(A) Delay distortion (B) Phase distortion
(D) All the above
ANS:D
17. What type of line appear to be of finite length terminated with Z0 to the sending end
generator?
A. Infinite line B. Finite line C. Short circuit line
D. Open circuit line
ANS:A
18.Which of the following defines the distance wave travels along the line while the phase angle
is changing through 2π radians?
A.Velocity
B.Wavelength
C.Time
D.Frequency
ANS:B
19. What is the equation for a characteristic impedance Zo in terms of impedance and
admittance?
(A) √𝒀/𝒁
(B) √𝒁/𝒀
(C) √𝒁𝒀
(C) Frequency distortion
(D) √𝟐𝒁𝒀
ANS:B
20. What is the equation for a Propagation constant of a transmission line in terms of impedance
and admittance?
(A) √𝒀/𝒁
(B) √𝒁/𝒀
(C) √𝒁𝒀
(D) √𝟐𝒁𝒀
ANS:C
21. For which type of wave the voltage or current decreases in amplitude with increasing
distance from the load ?
(A) incident wave
(B) medium wave
(C) reflected wave
(D) none of above
ANS: C
22. What is the equation for a characteristic impedance Zo in terms of open & short circuited
line?
A) √𝒁𝑺𝑪/𝒁𝑶𝑪
B) √𝒁𝑶𝑪/𝒁𝑺𝑪
C) √𝒁𝑺𝑪. 𝒁𝑶𝑪
D) (Z SC..Z OC)
23. What is the general parameters of a distributed transmission line?
(a) R&L only
(b) L&C only
(c) C&G only
ANS:C
(d) R, L, C&G
24. For which type of wave the voltage or current decreases in amplitude with increasing
distance from the source ?
(a) Incident wave
(b) medium wave
(c) reflected wave
ANS: D
(d) none of above
25. Find the characteristic impedance of the line If Zoc = 120Ω and Zsc = 30 Ω?
(A) 30 Ω
(B) 60 Ω
(C) 120 Ω
(D) 150 Ω
ANS: A
ANS: B
26. For a line of characteristic impedance, Z O terminated in a load, ZR such that ZR > ZO , the
Voltage Standing Wave Ratio (VSWR) is given by
ANS:A
27. Consider a transmission line of characteristic impedance 50 ohms and the line is terminated
at one end by +j50 ohms, the VSWR produced in the transmission line will be
(A) +1
(B) zero
(C) infinity
(D) -1
ANS: C
28. What is the value of VSWR when the line is in open circuit condition?
A) 0
(B) 1
(C) ∞
(D) –1
ANS: C
29. What is the value of the reflection coefficient of a transmission line with a short-circuited
load?
(A) 0.
(B) ∞ .
(C) 1 <0° (D) 1 <180°
ANS: D
30. What is the value of characteristic impedance when Zoc = 120Ω and Zsc = 30Ω?
(A) 30 Ω
(B) 60Ω
(C) 120 Ω
(D) 150 Ω
ANS: B
31.At what condition the reflection coefficient of a line is equal to −1?
(A) Open circuited.
(B) Short circuited.
(C) Terminated in Zo (D) Of infinite length.
Ans: B
32. If a transmission line of length less than λ/4 is short circuited, it behaves as
(A) Pure capacitive reactance.
(B) Series resonant circuit.
(C) Parallel resonant circuit.
(D) Pure inductive reactance.
ANS: D
33.What is the value of the Input impedance of a short-circuited lossless line with length λ/4 ?
(A) Z o
(B) zero
(C) infinity
(D) Z0 2
ANS: C
34. What is the value of the Input impedance of a open-circuited lossless line with length λ /4 ?
(A) Z o
(B) zero
(C) infinity
(D) Z0 2
ANS: B
35. For a transmission line, open circuit and short circuit impedances are 20Ω and 5Ω. The
characteristic impedance of the line is
(A) 100 Ω
(B) 50 Ω
(C) 25 Ω
(D) 10 Ω.
ANS: D
36. If K is the reflection coefficient and S is the Voltage standing wave ratio, then
37. What is the value of Voltage standing wave ratio, when Zo = 300<0Ω and ZL = 150<0Ω?
(A) 1
(B) 0.5
(C) 2
(D) ∞
ANS: C
38. When the reflection take place in the line?
(A) ZR=0
(B) ZR= ∞
(C) ZR=0 and ZR= ∞
(D) ZR=Zo
ANS: C
39.At what condition the maximum power is absorbed by one network from other, joined to it at
two terminals ?
(a) impedance of one= complex conjugate of other (b) impedance of one =square root of other
(c) impedance of one =same as other
(d) none of above
40.What is the range of Voltage standing wave ratio ?
(a) 0 to 1
(b) 1 to infinity
ANS: A
(c) 0 to infinity
(d) -1 to +1
ANS:B
41. What is the value of the reflection coefficient when the line is properly terminated with Z0?
(A) 0
(B) 1
(C) 2
(D) ∞
ANS: A
42.What is called as nodes?
a) Point of zero voltage or current
b) Point of maximum voltage or current
c) Point of minimum voltage or current
(d) none of above
ANS: A
43.What is called as antinodes?
a) Point of zero voltage or current
b) Point of maximum voltage or current
c) Point of minimum voltage or current
(d) none of above
ANS:B
44. What is the value of two successive voltage maxima?
a)λ/2
b)λ/4
c)λ/8
d)λ
ANS:A
45. What is the value of two successive voltage minima?
a)λ/2
b)λ/4
c)λ/8
d)λ
ANS:A
46. For a line of characteristic impedance, Z O terminated in a load, ZR such that ZR < ZO , the
Voltage Standing Wave Ratio (VSWR) is given by
47. What is the value of VSWR when the line is in short circuit condition?
A) 0
(B) 1
(C) ∞
ANS:D
(D) –1
ANS: A
48. What is the value of the reflection coefficient of a transmission line with a open-circuited
load?
(A) 0.
(B) ∞ .
(C) 1 <0°
(D) 0.1 . <180°
ANS: C
49.At what condition the reflection coefficient of a line is equal to 1?
(A) Open circuited.
(B) Short circuited.
(C) Terminated in Zo (D) Of infinite length.
Ans: A
50. What is the range of reflection coefficient ?
(a) 0 to 1
(b) 1 to infinity
(c) 0 to infinity
(d) -1 to +1
ANS:A
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References :
http://iete-elan.ac.in/SolQP/soln/DE07_sol.pdf
Dhananjayan“Transmission lines &Waveguides”Lakshmi Publications,Fifth Edition,2008
Faculty Signature:
Faculty Name: S.AROKIA MAGDALINE
HOD Signature