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# Microwave Engineering Multiple-Choice Questions (MCQs)

Microwave engineering is a subject of electrical engineering which is all about the study and design of microwave circuits, components, and systems.

Microwave Engineering MCQs: This section contains multiple-choice questions and answers on the various topics of Microwave Engineering. Practice these MCQs to test and enhance your skills on Microwave Engineering.

## List of Microwave Engineering MCQs

1. Microwaves travel in a ____.

1. Distorted line
2. Curves
3. Straight lines

Explanation:

Microwaves travel in a straight line.

2. Which of the following are the disadvantages of microwaves?

1. The cost of equipment or installation is prohibitively expensive.
2. They are heavier and take up more room
3. Electromagnetic interference is possible
4. All of the above

Answer: D) All of the above

Explanation:

Following are the cons of microwaves:

• The cost of equipment or installation is prohibitively expensive
• They are heavier and take up more room
• Electromagnetic interference is possible

3. A ____ is a connection that sends energy from one location to another.

1. Transmission line
2. Cable lines
3. Fibre cable lines
4. Modem line

Explanation:

A transmission line is a connection that sends energy from one location to another.

4. How many types of transmission lines are there?

1. 5
2. 4
3. 3
4. 2

Explanation:

There are four types of transmission lines:

• Two-wire parallel transmission lines
• Coaxial lines
• Strip-type substrate transmission lines
• Waveguides

5. Which of the following is a crucial parameter of transmission lines?

1. Resistance
2. Inductance
3. Capacitance
4. Conductance
5. All of the above

Answer: E) All of the above

Explanation:

Resistance, inductance, capacitance, and conductance are significant transmission line attributes.

6. The combination of resistance and inductance is called ____.

1. Transmission lines Susceptibility
2. Transmission lines Resistivity
3. Transmission line impedance

Explanation:

Transmission line impedance is the combination of resistance and inductance.

7. The combination of Capacitance and conductance are called ____.

1. Transmission lines Susceptibility
2. Transmission lines Resistivity
3. Transmission line impedance

Explanation:

Transmission line admittance is the combination of Capacitance and conductance.

8. The resistance of a line is mostly affected by ____.

1. Temperature
2. Current frequency
3. Only A
4. Only B
5. Both A and B

Answer: E) Both A and B

Explanation:

The resistance of a line is mostly affected by temperature and current frequency.

9. As a conductor's temperature increases, its resistance changes ____.

1. Inversely
2. Exponentially
3. Non-linearly
4. Linearly

Explanation:

As a conductor's temperature increases, its resistance changes linearly.

10. The current density towards the surface of a conductor ____ with the frequency of the current.

1. Increases
2. Decreases
3. Remain same

Explanation:

The current density towards the surface of a conductor increases with the frequency of the current.

11. ____ refers to a conductor's ability to resist changes in current flow.

1. Resistance
2. Conductance
3. Inductance

Explanation:

Inductance refers to a conductor's ability to resist changes in current flow.

12. Which of the following is used to represent inductance?

1. I
2. K
3. P
4. L

Explanation:

Inductance is represented by Letter L.

13. Which of the following is the SI unit of inductance?

2. Henry
3. Weber
4. Volt meters

Explanation:

The SI unit of inductance is Henry.

14. Conductance is denoted by ____.

1. I
2. K
3. C
4. G

Explanation:

Conductance is denoted by G.

15. Which of the following statement is True?

1. Capacitance is related to the electric field, while inductance is related to the magnetic field
2. Capacitance is related to the magnetic field, while inductance is related to the electric field

Answer: A) Capacitance is related to the electric field, while inductance is related to the magnetic field.

Explanation:

Capacitance is related to the electric field, while inductance is related to the magnetic field.

16. Which of the following is used to denote the Characteristic Impedance in microwave engineering?

1. C0
2. A~
3. Z0
4. Z0

Explanation:

Z0 is used to denote the Characteristic Impedance in microwave engineering.

17. Which of the following statement is TRUE?

1. Reflection coefficient is the metric that describes the amount of reflected energy caused by Characteristic Impedance in a transmission line
2. Reflection coefficient is the metric that describes the amount of reflected energy caused by an impedance mismatch in a transmission line

Answer: B) Reflection coefficient is the metric that describes the amount of reflected energy caused by an impedance mismatch in a transmission line.

Explanation:

The reflection coefficient is the metric that describes the amount of reflected energy caused by an impedance mismatch in a transmission line.

18. Reflection coefficient is represented by ____.

1. Alpha
2. Beta
3. Rho
4. Delta

Explanation:

The reflection coefficient is represented by rho.

19. Which of the following is the correct formula for the reflection coefficient?

1. ρ=reflected voltage/incident voltage
2. ρ=incident voltage**reflected voltage
3. ρ=reflected voltage incident voltage
4. None

Explanation:

Reflection coefficient ρ=reflected voltage/incident voltage.

20. What is the full form of VSWR in the context of microwave engineering?

1. Vibration simplification wave ratio
2. Vibration standing wave ratio
3. Voltage simplification wave ratio
4. Voltage standing wave ratio

Answer: D) Voltage standing wave ratio

Explanation:

VSWR stands for voltage standing wave ratio.

21. Which of the following is True about VSWR?

1. VSWR is defined as the ratio between maximum Characteristic Impedance and minimum Characteristic Impedance in a standing wave
2. VSWR is defined as the ratio between maximum impedance mismatch and minimum voltage in a standing wave
3. VSWR is defined as the ratio between the maximum voltage and minimum voltage in a standing wave
4. VSWR is defined as the ratio between the maximum voltage and minimum impedance mismatch in a standing wave

Answer: C) VSWR is defined as the ratio between the maximum voltage and minimum voltage in a standing wave.

Explanation:

VSWR is defined as the ratio between the maximum voltage and minimum voltage in a standing wave.

22. VSWR is denoted by ____.

1. V
2. Q
3. S
4. VR

Explanation:

VSWR is denoted by S.

23. The greater the impedance mismatch, the ____ standing wave amplitude.

1. Lesser
2. Greater
3. No effect

Explanation:

The greater the impedance mismatch, the Greater standing wave amplitude.

24. What do you mean by the efficiency of transmission lines?

1. The ratio of power reflected from one end of a transmission line to the power absorbed at the other end is known as transmission line efficiency
2. The ratio of power transported from one end of a transmission line to power provided at the other end is known as transmission line efficiency

Answer: B) The ratio of power transported from one end of a transmission line to power provided at the other end is known as transmission line efficiency.

Explanation:

The ratio of power transported from one end of a transmission line to power provided at the other end is known as transmission line efficiency.

25. The amount of the voltage difference between the transmitting and receiving ends of a transmission line is characterized as ____.

1. Register regulation
2. Voltage regulation
3. Attenuation Loss
4. Efficiency of transmission lines

Explanation:

The amount of the voltage difference between the transmitting and receiving ends of a transmission line is characterized as voltage regulation.

26. The loss caused by signal absorption in the transmission line is known as ____ loss.

1. Attenuation loss
2. Reflection loss
3. Transmission loss
4. Return loss

Explanation:

The loss caused by signal absorption in the transmission line is known as attenuation loss.

27. An impedance mismatch of the transmission line causes signal reflection, resulting in ____ loss.

1. Insertion loss
2. Reflection loss
3. Transmission loss
4. Return loss

Explanation:

An impedance mismatch of the transmission line causes signal reflection, resulting in reflection loss.

28. The loss that occurs during the transmission process through the transmission line is referred to as ____ loss.

1. Insertion loss
2. Reflection loss
3. Transmission loss
4. Return loss

Explanation:

The loss that occurs during the transmission process through the transmission line is referred to as transmission loss.

29. What is return loss?

1. Return loss is a measure of how much power is absorbed by the transmission line
2. Return loss is a measure of how much power is reflected by the transmission line

Answer: B) Return loss is a measure of how much power is reflected by the transmission line.

Explanation:

Return loss is a measure of how much power is reflected by the transmission line.

30. ____ loss is the loss that happens as a result of energy transfer across a transmission line vs energy transfer without a transmission line.

1. Insertion loss
2. Reflection loss
3. Transmission loss
4. Return loss

Explanation:

Insertion loss is the loss that happens as a result of energy transfer across a transmission line vs energy transfer without a transmission line.

31. How many stub-matching approaches are used at higher microwave frequencies?

1. 5
2. 4
3. 3
4. 2

Explanation:

Two stub matching approaches are used at higher microwave frequencies:

• Single stub matching
• Double stub matching

32. Which stub matching method is only utilized for a specified frequency?

1. Single stub matching
2. Double stub matching

Explanation:

Single stub matching method is only utilized for a specified frequency.

33. As a single frequency matching device, ____ stub matching is commonly utilized in laboratory practice.

1. Single stub matching
2. Double stub matching

Explanation:

As a single-frequency matching device, double stub matching is commonly utilized in laboratory practice.

34. The electric and magnetic fields in which mode of propagation are truly perpendicular to the direction of wave propagation?

1. TEM (Transverse Electromagnetic Wave)
2. TE Transverse Electric Wave)
3. TM (Transverse Magnetic Wave)
4. HE (Hybrid Wave)

Answer: A) TEM (Transverse Electromagnetic Wave)

Explanation:

The electric and magnetic fields in the TEM mode of propagation are truly perpendicular to the direction of wave propagation.

35. In which mode of propagation, neither electric nor magnetic field are truly perpendicular to the direction of wave propagation?

1. TEM (Transverse Electromagnetic Wave)
2. TE Transverse Electric Wave)
3. TM (Transverse Magnetic Wave)
4. HE (Hybrid Wave)

Explanation:

In the HE (Hybrid wave) mode, neither electric nor magnetic fields are truly perpendicular to the direction of wave propagation.

36. Transmission lines used at microwave frequencies can be roughly categorized into how many categories?

1. 5
2. 4
3. 3
4. 2

Explanation:

Transmission lines used at microwave frequencies can be roughly categorized into three categories:

• Multi-conductor lines
• Single conductor lines
• Open boundary structures

37. Transmission lines with more than one conductor falls under which category of transmission lines used at microwave frequencies?

1. Multi-conductor lines
2. Single conductor lines
3. Open boundary structures

Explanation:

Transmission lines with more than one conductor falls under the multi-conductor lines category of transmission lines used at microwave frequencies.

38. Which of the following does not come under the multiconductor lines?

1. Co-axial lines
2. Strip lines
3. Microstrip lines
4. Di-electric rods

Explanation:

Di-electric rods do not come under multiconductor lines.

39. Does coaxial cable support all frequencies?

1. Yes
2. No

Explanation:

The coaxial cable has no cut-off frequency. It supports all frequencies.

40. A ____ is a hollow metallic tube with a consistent cross-section for transmitting electromagnetic waves by consecutive reflections off the tube's interior walls.

1. Waveguide
2. Magnetic lines
3. Group velocity
4. Traverse magnetic mode

Explanation:

A Waveguide is a hollow metallic tube with a consistent cross-section for transmitting electromagnetic waves by consecutive reflections off the tube's interior walls.

41. How many types of waveguides are there?

1. 6
2. 5
3. 4
4. 9

Explanation:

There are five types of waveguides:

• Rectangular waveguide
• Circular waveguide
• Elliptical waveguide
• Single-ridged waveguide
• Double-ridged waveguide

42. Does waveguides support TEM waves?

1. Yes
2. No

Explanation:

No, waveguides do not support TEM waves.

43. Which of the following is True about waveguides?

1. All frequencies are allowed to pass through
2. Only frequencies larger than the cut-off frequency can pass through
3. Both
4. None

Answer: B) Only frequencies larger than the cut-off frequency can pass through.

Explanation:

In waveguides, only frequencies larger than the cut-off frequency can pass through.

44. What is the cut-off frequency?

1. The highest frequency at which a waveguide mode may propagate without being attenuated
2. The lowest frequency at which a waveguide mode may propagate without being attenuated

Answer: B) The lowest frequency at which a waveguide mode may propagate without being attenuated.

Explanation:

Cut-off frequency is defined as the lowest frequency at which a waveguide mode may propagate without being attenuated.

45. Which of the following has a characteristic impedance?

1. Transmission lines
2. Waveguides

Explanation:

Transmission lines have a characteristic impedance whereas waveguides have a wave impedance.

46. Bandwidth in waveguides is ____.

1. Limited
2. Unlimited

Explanation:

Bandwidth in waveguides is Limited.

47. What is phase velocity?

1. The speed with which the phase of a transmission line propagates across a fixed medium is referred to as phase velocity
2. The speed with which the phase of a transmission line propagates across a fixed bandwidth is referred to as phase velocity
3. The speed with which the phase of a wave propagates across a medium is referred to as phase velocity

Answer: C) The speed with which the phase of a wave propagates across a medium is referred to as phase velocity.

Explanation:

The speed with which the phase of a wave propagates across a medium is referred to as phase velocity.

48. The pace at which the wave propagates through the waveguide is referred to as ____ velocity.

1. Transmission velocity
2. Wave velocity
3. Group velocity
4. Total velocity

Explanation:

The pace at which the wave propagates through the waveguide is referred to as group velocity.

49. Varactor diode is a ____ device.

1. Semiconductor
2. Conductor
3. Insulator

Explanation:

Varactor diode is a semiconductor device.

50. Which diodes are most commonly used in microwave detection and mixing?

1. Zener diode
2. Light-emitting diode
3. Schottky Barrier diode
4. Photodiode

Explanation:

Schottky barrier diodes are most commonly used in microwave detection and mixing.

51. Which of the following devices fall into the category of Avalanche transit time devices?

1. MPATT diodes
2. RAPATT diodes
3. BARITT diodes
4. All of the above

Answer: D) All of the above

Explanation:

MPATT, TRAPATT, and BARITT are examples of Avalanche transit time devices.

52. What is the full form of IMPATT?

1. IMPact ionization Avalanche Transit Time diode
2. IMPortant Ion Avalanche Transit Time diode
3. IMPression ionization Avalanche Transit Time diode

Answer: A) IMPact ionization Avalanche Transit Time diode.

Explanation:

The full form IMPATT is IMPact ionization Avalanche Transit Time diode.

53. When a voltage gradient is supplied to the IMPATT diode, it produces a ____ current.

1. High
2. Low

Explanation:

When a voltage gradient is supplied to the IMPATT diode, it produces a high current.

54. What is the full form of the TRAPATT diode?

1. TRAnsmit Plasma Avalanche Triggered Transit diode
2. TRAnsmission Plasma Avalanche Triggered Transit diode
3. TRApped Plasma Avalanche Triggered Transit diode

Answer: C) TRApped Plasma Avalanche Triggered Transit diode.

Explanation:

The full form of the TRAPATT diode is the TRApped Plasma Avalanche Triggered Transit diode.

55. What is the full form of the BARITT Diode?

1. BARd Injection Transit Time diode
2. BARrier Injection Transit Time diode
3. BARely Injection Transit Time diode

Answer: B) BARrier Injection Transit Time diode.

Explanation:

The full form of the BARITT Diode is the BARrier Injection Transit Time diode.

56. How many types of hybrid integrated circuits are there?

1. 5
2. 4
3. 3
4. 2

Explanation:

There are two types of hybrid integrated circuits:

• Hybrid IC
• Miniature Hybrid IC

57. What do you mean by Tee junction?

1. A TEE junction is a waveguide in a microwave circuit that includes two combined ports
2. A TEE junction is a waveguide in a microwave circuit that includes two integrated ports
3. A TEE junction is a waveguide in a microwave circuit that includes three separate ports

Answer: C) A TEE junction is a waveguide in a microwave circuit that includes three separate ports.

Explanation:

A TEE junction is a waveguide in a microwave circuit that includes three separate ports.

58. The plane containing the electric field vector is known as the ____.

1. E-plane
2. H-plane
3. E-H plane

Explanation:

The plane containing the electric field vector is known as the E-plane.

59. The plane containing the magnetic field vector is known as the ____.

1. E-plane
2. H-plane
3. E-H plane

Explanation:

The plane containing the magnetic field vector is known as the H-plane.

60. Which of the following is True about the Directional Coupler?

1. A Directional Coupler is a One-port waveguide junction
2. A Directional Coupler is a Two-port waveguide junction
3. A Directional Coupler is a Three-port waveguide junction
4. A Directional Coupler is a four-port waveguide junction

Answer: D) A Directional Coupler is a four-port waveguide junction.

Explanation:

A Directional Coupler is a four-port waveguide junction.

61. What is magnetron?

1. A magnetron is a device that produces powerful electric waves
2. A magnetron is a device that produces powerful magnetic waves
3. A magnetron is a device that produces powerful electromagnetic waves

Answer: C) A magnetron is a device that produces powerful electromagnetic waves.

Explanation:

A magnetron is a device that produces powerful electromagnetic waves.

62. How many types of magnetrons are there?

1. 5
2. 3
3. 4
4. 7

Explanation:

Magnetrons are classified into three categories.

• Negative Resistance type
• Cyclotron Frequency Magnetrons
• Type of Cavity or Travelling Wave

63. Which of the following magnetron type is used at low frequencies?

1. Negative Resistance type
2. Cyclotron Frequency Magnetrons
3. Type of Cavity or Travelling Wave

Explanation:

Negative Resistance type magnetron is used at low frequencies <500MHz.

64. Which of the following is an example of a microwave signal generator?

1. Gunn diode oscillator
2. Reflex Klystron tube
3. Both

Explanation:

A Gunn diode oscillator or a Reflex Klystron tube could be an example of a microwave signal generator.

65. The level of attenuation is determined by which attenuator?

1. Precision attenuator
2. Variable Attenuator

Explanation:

The level of attenuation is determined by the Variable Attenuator.

66. Which device is used to measure low microwave power?

1. Bolometer
2. Calorimeter
3. Attenuation meter

Explanation:

A bolometer is a device used to measure low microwave power.

67. ____ are commonly used to measure high microwave power.

1. Bolometer
2. Calorimetric watt meters
3. Attenuation meter

Explanation:

Calorimetric watt meters are commonly used to measure high microwave power.

68. Attenuation normally expressed in ____.

1. Candela
2. Ohm
3. Hertz
4. Decibels
5. Variable Attenuator

Explanation:

Attenuation is normally expressed in decibels.

69. What is a tunable detector

1. A tunable detector is a detector mount that detects low-frequency square wave-modulated electromagnetic waves
2. A tunable detector is a detector mount that detects low-frequency square wave modulated mechanical waves
3. A tunable detector is a detector mount that detects low-frequency square wave modulated microwave waves
4. A tunable detector is a detector mount that detects low-frequency square wave modulated gravitational waves

Answer: C) A tunable detector is a detector mount that detects low-frequency square wave modulated microwave waves.

Explanation:

A tunable detector is a detector mount that detects low-frequency square wave modulated microwave waves.

70. How many types of tunable stubs are there?

1. 5
2. 4
3. 6
4. 3

Explanation:

There are three different types of tunable stubs.:

1. Tunable waveguide detector
2. Tunable co-axial detector
3. Tunable probe detector