🧪 Electrical engineering MCQ Quiz Hub

1. The value of ‘α’ for a lossless line is:
0
1
Infinity
Data insufficient

2. If propagation constant is 12:60°, then the value of phase constant and attenuation constant is:
α=6, β=10.39
α=61, β=78
α=12, β=20.6
none of the mentioned

3. If a transmission line with inductive reactance of 41.97 Ω and capacitive reactance of 1132.5Ω is operated at 1 GHz , then its phase constant is:
0.0305
0.3
30.3
0.6

4. If the admittance and the impedance of a transmission line are 100 Ω and 50 Ω of a respectively, then value of phase constant β is:
0
20
132
50

5. For a lossless line, which of the following is true?
γ=jβ
γ=α
γ=α+jβ
γ=α*jβ

6. Expression for phase constant β is:
√LC
ω √LC
1/ (ω √LC)
None of the mentioned

7. A microwave generator at 1.2 GHz supplies power to a microwave transmission line having the parameters R=0.8Ω/m, G=O.8millisiemen/m, L=0.01µH/m and C=0.4PF/m. Propagation constant of the transmission line is:
0.0654 +j0.48
0.064+j4.8
6.4+j4.8
none of the mentioned

8. In a certain microwave transmission line, the characteristic impedance was found to be 210 10°Ω and propagation constant 0.2 78°.What is the impedance Z of the line, if the frequency of operation is 1 GHz?
0.035+j41.97
0.35+j4.97
35.6+j4.28
9.254+j4.6

9. For a transmission line, L=1.8mh/m C=0.01pF/m, then the phase constant of the line when operated at a frequency of 1 GHz is:
4.2426
2.2
0.3
1

10. In a two wire transmission line, if the distance between the lines is 20 mm and the radii is 5 mm then the inductance of the line is:
0.1 µH
0.526 µH
0.9 µH
1 µH

11. In a two wire transmission line , if the distance between the lines is 60mm and the radii is 10 mm , then the capacitive reactance of the line when operated at 12.5 GHz is
20 pF
21.13 pF
23 pF
12 pF

12. The wave impedance of air for a wave propagating in it is:
377 Ω
345 Ω
Insufficient data
None of the mentioned

13. Wave impedance of a wave travelling in a medium of a relative permittivity 2 and permeability 4 is
188.5 Ω
200 Ω
300 Ω
None of the mentioned

14. For a parallel plate transmission line, if w= 12 mm and the distance between the plates is 2 mm, then the inductance of the transmission line is:
0.2 µH
0.1 µH
0.3 µH
0.4 µH

15. If the distance between the 2 wires in a 2 wire transmission line is 10 mm and the radii 2 mm, then the inductance of the transmission line is:
0.62 µH
1 µH
2 µH
None of the mentioned

16. For a parallel plate transmission line, if the complex part of permittivity is 2.5, if the width is 100 mm and the distance between the plates is 10 mm, then the conductance of the transmission line is:
25 Ʊ
30 Ʊ
45 Ʊ
None of the mentioned

17. For a parallel plate transmission line, if the series resistance is 10 mΩ/m, and the width is 100 mm, then the resistance of the transmission line is:
0.2 Ω
1 Ω
2 Ω
5 Ω

18. If the outer and the inner diameter of a coaxial transmission line are 20 mm and 10 mm respectively, then the inductance /m of the transmission line is:
0.13 µH
0.2 µH
0.3 µH
0.1 µH

19. If the outer circumference and the inner circumference of a transmission line are 40π and 25π units respectively, then the capacitive reactance of the coaxial transmission line is:
0.376 nF
0.45 nF
0.9 nF
none of the mentioned

20. For a 2 wire transmission line, if the complex part of permittivity is 2.5, then the given distance between the 2 wires is 10mm and operated at a frequency of 1.2 MHz and the radius of the line being 5mm, then the conductance of the transmission line is:
0.2 µH
0.1 µH
0.5 µH
1 µH

21. Characteristics impedance of a coaxial line with external and inner diameter 5mm is:
40 Ω
41.58 Ω
47.78 Ω
54.87 Ω

22. The characteristic impedance of the transmission line if the outer diameter and inner diameter of the transmission line is 20 mm and 10 mm respectively, given the intrinsic impedance of the medium is 377 Ω, then the characteristic impedance of the transmission line is:
41.58 Ω
50 Ω
377 Ω
None of the mentioned

23. Flow of power in transmission line takes place through:
Electric field and magnetic field
Voltage and current
Voltage
Electric field

24. When a transmission line is exited by a source, total power supplied is delivered to the load.
True
False

25. Input impedance of a transmission line can be represented in terms of this simple trigonometry function.
sine function
cosine function
cotangent function
tangent function

26. Input impedance of a open circuited transmission line is represented using this trigonometric function:
sine function
cosine function
cotangent function
tangent function

27. For a λ/2 transmission line, if the characteristic impedance of the line is 50 Ω and the terminated with a load of 100 Ω, then its input impedance is:
100Ω
50Ω
88.86Ω
none of the mentioned

28. If a λ/3 transmission line is open circuited and has characteristic impedance of 50 Ω then the input impedance is:
j28.86Ω
50Ω
j50Ω
28.86Ω

29. For a transmission line, if the reflection coefficient is 0.4, then the transmission coefficient is:
0.4
1.4
0.8
2.8

30. If the transmission coefficient of a transmission line is 1.6, then the reflection co efficient is:
0.8
0.6
0.4
0.3

31. For a transmission line, if the transmission coefficient is 1.4, then the insertion loss in dB is:
-2.922dB
29dB
1.46dB
-29dB

32. The relation between nepers and decibels is:
1 Np= 8.686 dB
1 dB=8.868 dB
Np≥dB
dB≥Np

33. Smith chart is based on the polar plot of:
Reactance
Voltage
Current
Voltage reflection co-efficient

34. Any passively realizable reflection coefficient can be plotted as a unique point on the smith chart. This statement implies that:
Reflection co-efficient less than or equal to 1 can be plotted
Reflection co-efficient greater than or equal to 1 can be plotted
Transmission co-efficient has to be less than or equal to one for the point to be located
T=Г+1

35. If the characteristic impedance of a ƛ/2 transmission line is 50 Ω and reflection coefficient 0.3, then its input impedance
26.92 Ω
30 Ω
40 Ω
34.87 Ω

36. If the normalized input impedance of a transmission line is 0.5 Ω, then he reflection coefficient of a ƛ/2 transmission line is
0.3334
0.5
0.6667
1

37. If the input impedance of a ƛ/2 transmission line is 100 Ω with a voltage reflection coefficient of 0.344, then the characteristic impedance of the transmission line is:
200 Ω
100 Ω
50 Ω
None of the mentioned

38. Normalized impedance of 0.3+j0.4 lies in the:
Upper half of the impedance smith chart
Lower half of the impedance smith chart
Horizontal line of the chart
None of the mentioned

39. Normalized impedance of 1-j is:
In the upper half of the impedance smith chart
In the Lower half of the impedance smith chart
On the outer most circle of the smith chart.
On the horizontal line of the smith chart

40. If a transmission line of a characteristic impedance 100 Ω is terminated with a load impedance of 300+j200 Ω, then the normalized load impedance is:
1+j
1-j
3+2j
2-3j

41. If the normalized load impedance of a transmission line is 0.3-j0.4 with a characteristic impedance of 50 Ω, then the load impedance is:
15-j20
15+j20
1-j
0.3-0.4j

42. To get an admittance chart from an impedance chart:
Smith chart has to be rotated by 90⁰
Smith chart has to be rotated by 180⁰
Admittance chart cannot be obtained from the impedance chart anyway.
None of the mentioned

43. If a transmission line of characteristic impedance 50 Ω is to be matched to a load of 100Ω, then the characteristic impedance of the ƛ/4 transmission line to be used is:
70.71 Ω
50 Ω
100 Ω
75 Ω

44. If a λ/4 transmission line is 100Ω is used to match a transmission line to a load of 100Ω, then the characteristic impedance of the transmission line is:
100 Ω
50 Ω
70.71 Ω
200 Ω

45. If there is no standing wave on a transmission line, then the value of SWR is:
1
0
Infinity
Insufficient data

46. When a λ/4 transmission line is used for impedance matching, then which of the following is valid?
Standing waves are present on the λ/4 transmission line
No standing waves on the λ/4 transmission line
Standing waves are not present both on the feed line and the matching λ/4 line
Standing waves are present on both the feed line and the matching λ/4 line

47. For a transmission line , if the input impedance of the transmission line is 100Ω with a characteristic impedance of 150Ω, then the magnitude of the reflection co efficient:
0.5
1
0.2
0

48. If the reflection co-efficient of a transmission line is 0.334 with a characteristic impedance of 50Ω then the input impedance of the transmission line is:
100 Ω
50 Ω
150 Ω
None of the mentioned

49. The value of reflection co efficient when a transmission line is matched to the load is:
1
0
0.707
cannot be determined

50. The value of transmission co efficient when a transmission line is matched to a load is:
1
0
0.5
0.707