MCQOPTIONS
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MCQOPTIONS
This section includes 247 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The radar in which both transmission and reception is done using the sameantenna are called: |
| A. | monostatic |
| B. | bistatic |
| C. | dipole radar |
| D. | monopole radar |
| Answer» B. bistatic | |
| 2. |
__________ system obtains information about a target by transmitting a signaland receiving the echo from the target. |
| A. | radar |
| B. | sonar |
| C. | radiometer |
| D. | none of the above |
| Answer» B. sonar | |
| 3. |
If a transmission line of a characteristics impedance 50 is terminated with a load impedance of 100 , then the reflection co efficient is: |
| A. | 0.3334 |
| B. | 0.6667 |
| C. | 1.6 |
| D. | 1.333 |
| Answer» B. 0.6667 | |
| 4. |
If a transmission line of characteristic impedance 50 is to be matched to a load of 100 , then the characteristic impedance of the /4 transmission line to be used is: |
| A. | 75 |
| B. | 50 |
| C. | 100 |
| D. | 70.71 |
| Answer» E. | |
| 5. |
If a transmission line of characteristic impedance 50 is terminated with a load impedance of 150 , then VSWR is: |
| A. | 0.75 |
| B. | 0.5 |
| C. | 2 |
| D. | none of the mentioned |
| Answer» B. 0.5 | |
| 6. |
Indicate the false statement. The SWR on a transmission line is infinity; the line isterminated in |
| A. | a short circuit |
| B. | an open circuit |
| C. | a complex impedance |
| D. | pure reactance |
| Answer» D. pure reactance | |
| 7. |
Considering a coaxial transmission line, maximum voltage on the line divided bythe minimum voltage equals the |
| A. | characteristic impedance |
| B. | iswr |
| C. | vswr |
| D. | inductive reactance |
| Answer» D. inductive reactance | |
| 8. |
ency forthe dominant mode is |
| A. | 2.5 ghz |
| B. | 10 ghz |
| C. | 5 ghz |
| D. | 12.5 ghz |
| Answer» B. 10 ghz | |
| 9. |
The phase velocity of an electrometric wave propagating in a hollow metallicrectangular waveguide in the TE10 mode is |
| A. | equal to its group velocity |
| B. | less than velocity of light in free space |
| C. | equal to velocity of light in free space |
| D. | greater than velocity of light in free space |
| Answer» D. greater than velocity of light in free space | |
| 10. |
. Consider an air filled rectangular waveguide with a cross section of5 cm 3 cm.For this waveguide, the cut off frequency (in MHz) of TE21mode is |
| A. | 7.81 ghz |
| B. | 9.01 ghz |
| C. | 11.2 ghz |
| D. | 6.89 ghz |
| Answer» B. 9.01 ghz | |
| 11. |
ency of 30GHz is (free space impedance 0 =377 ) |
| A. | 308 |
| B. | 400 |
| C. | 355 |
| D. | 461 |
| Answer» C. 355 | |
| 12. |
A directional coupler with three or more holes is sometimes used in preference tothe two-hole couple |
| A. | because it is more efficient |
| B. | to increase coupling of signal |
| C. | to reduce spurious mode generation |
| D. | to increase the bandwidth of the system |
| Answer» D. to increase the bandwidth of the system | |
| 13. |
A microwave tube amplifier uses an axial magnetic field and a radial electric field.This is the |
| A. | reflex klystron |
| B. | coaxial magnetron |
| C. | travelling wave magnetron |
| D. | cfa |
| Answer» C. travelling wave magnetron | |
| 14. |
The load is properly matched with the transmission line if the standing wave ratiois equal to |
| A. | 50 |
| B. | 10 |
| C. | 5 |
| D. | 1 |
| Answer» E. | |
| 15. |
The TWT is sometimes preferred to the magnetron as a radar transmitter outputtube because it is |
| A. | capable of a longer duty cycle |
| B. | a more efficient bandwidth |
| C. | more broadband |
| D. | less noisy |
| Answer» B. a more efficient bandwidth | |
| 16. |
A magnetron whose oscillating frequency is electronically adjustable over a widerange is called a |
| A. | coaxial magnetron |
| B. | dither-tuned magnetron |
| C. | frequency agile magnetron |
| D. | vtm |
| Answer» E. | |
| 17. |
In a transmission line, if the SWR or maximum current to a minimum currentratio of 2:1, the ratio of the maximum voltage to the minimum voltage is |
| A. | 1:4 |
| B. | 4:1 |
| C. | 1:2 |
| D. | 2:1 |
| Answer» E. | |
| 18. |
A rectangular air filled waveguide has a cross section of 4 10 Theminimum frequency which can propagation in the waveguide is |
| A. | 1.5 ghz |
| B. | 2.5 ghz |
| C. | 2.0 ghz |
| D. | 3.0 ghz |
| Answer» B. 2.5 ghz | |
| 19. |
A loss less line of characteristic impedance Z0 is terminated in pure reactance of -jZ0 value. VSWR is |
| A. | 10 |
| B. | 2 |
| C. | 1 |
| D. | infinity |
| Answer» E. | |
| 20. |
Indicate which one of the following modes do not exist in a rectangularresonantcavity |
| A. | te110 |
| B. | tm110 |
| C. | te011 |
| D. | mt111 |
| Answer» B. tm110 | |
| 21. |
For TE1 mode, if the waveguide is filled with air and the broader dimension of the waveguide is 2 cm, then the cutoff frequency is: |
| A. | 5 mhz |
| B. | 7.5 mhz |
| C. | 7.5 ghz |
| D. | 5 ghz |
| Answer» D. 5 ghz | |
| 22. |
The load is properly matched with the transmission line if the standing wave ratiois equal to |
| A. | 50 |
| B. | 10 |
| C. | 5 |
| D. | 1 |
| Answer» E. | |
| 23. |
The TWT is sometimes preferred to the magnetron as a radar transmitter outputtube because it is |
| A. | capable of a longer duty cycle |
| B. | a more efficient bandwidth |
| C. | more broadband |
| D. | less noisy |
| Answer» B. a more efficient bandwidth | |
| 24. |
In TM mode, if the direction of wave propagation is in ‘z’ direction, then: |
| A. | hz=0 |
| B. | ez=0 |
| C. | ey=0 |
| D. | hy=0 |
| Answer» B. ez=0 | |
| 25. |
The substrate of an MMIC must be a _____________ to accommodate thefabrication of all the type of devices. |
| A. | semiconductor |
| B. | insulator |
| C. | partial conductors |
| D. | metals operable at high frequencies |
| Answer» B. insulator | |
| 26. |
For dominant mode propagation in TE mode, if the rectangular waveguide has a broaderdimension of 31.14 mm , then the cutoff wave number: |
| A. | 100 |
| B. | 500 |
| C. | 50 |
| D. | 1000 |
| Answer» B. 500 | |
| 27. |
Considering a coaxial transmission line, maximum voltage on the line divided bythe minimum voltage equals the |
| A. | characteristic impedance |
| B. | iswr |
| C. | vswr |
| D. | inductive reactance |
| Answer» D. inductive reactance | |
| 28. |
When a reverse bias voltage exceeding the breakdown voltage is applied to anIMPATT diode, it results in: |
| A. | break down of depletion region |
| B. | avalanche multiplication |
| C. | high reverse saturation current |
| D. | none of the mentioned |
| Answer» C. high reverse saturation current | |
| 29. |
A “circulator” is a device that: |
| A. | rotates signal polarity in a waveguide |
| B. | allows a signal to pass in one direction only |
| C. | separates signals among various ports |
| D. | prevents microwaves from being “trapped” in a waveguide |
| Answer» D. prevents microwaves from being “trapped” in a waveguide | |
| 30. |
cm and b = 1.5 cm with μ = 1 and ε = 2.25 is |
| A. | 377 ohm |
| B. | 327 ohm |
| C. | 227 ohm |
| D. | 127 ohm |
| Answer» D. 127 ohm | |
| 31. |
________ is a single cavity klystron tube that operates as on oscillator by using areflector electrode after the cavity. |
| A. | backward wave oscillator |
| B. | reflex klystron |
| C. | travelling wave tube |
| D. | magnetrons |
| Answer» C. travelling wave tube | |
| 32. |
TEₒₒ mode for a rectangular waveguide: |
| A. | exists |
| B. | exists but defined only under special cases |
| C. | does not exist |
| D. | cannot be determined |
| Answer» D. cannot be determined | |
| 33. |
In a transmission line, if the SWR or maximum current to a minimum currentratio of 2:1, the ratio of the maximum voltage to the minimum voltage is |
| A. | 1:4 |
| B. | 4:1 |
| C. | 1:2 |
| D. | 2:1 |
| Answer» E. | |
| 34. |
A microwave tube amplifier uses an axial magnetic field and a radial electric field.This is the |
| A. | reflex klystron |
| B. | coaxial magnetron |
| C. | travelling wave magnetron |
| D. | cfa |
| Answer» C. travelling wave magnetron | |
| 35. |
A magnetron whose oscillating frequency is electronically adjustable over a widerange is called a |
| A. | coaxial magnetron |
| B. | dither-tuned magnetron |
| C. | frequency agile magnetron |
| D. | vtm |
| Answer» E. | |
| 36. |
The reflection coefficient of a transmission line having characteristic and load impedancesas 50 and 30 ohm respectively is |
| A. | 1/4 |
| B. | 1/8 |
| C. | 1/2 |
| D. | 3/4 |
| Answer» B. 1/8 | |
| 37. |
The maximum theoretical output circuit efficiency of a double resonator klystronamplifier is |
| A. | 25% |
| B. | 50% |
| C. | 58% |
| D. | 85% |
| Answer» D. 85% | |
| 38. |
The major advantage of single stub tuning over other impedance matchingtechniques is: |
| A. | lumped elements are avoided |
| B. | it can be fabricated as a part of transmission line media |
| C. | it involves two adjustable parameters |
| D. | all of the mentioned |
| Answer» E. | |
| 39. |
For TE1ₒ mode, if the waveguide is filled with air and the broader dimension of thewaveguide is 2 cm, then the cutoff frequency is: |
| A. | 5 mhz |
| B. | 7.5 mhz |
| C. | 7.5 ghz |
| D. | 5 ghz |
| Answer» D. 5 ghz | |
| 40. |
. Consider an air filled rectangular waveguide with a cross – section of5 cm × 3 cm.For this waveguide, the cut off frequency (in MHz) of TE21mode is |
| A. | 7.81 ghz |
| B. | 9.01 ghz |
| C. | 11.2 ghz |
| D. | 6.89 ghz |
| Answer» B. 9.01 ghz | |
| 41. |
The width of depletion region of a varactor diode ________with increase in reversebias voltage. |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | none of the mentioned |
| Answer» B. decreases | |
| 42. |
If a transmission line of characteristic impedance 50 Ω is to be matched to a load of100Ω, then the characteristic impedance of the ƛ/4 transmission line to be used is: |
| A. | 75 Ω |
| B. | 50 Ω |
| C. | 100 Ω |
| D. | 70.71 Ω |
| Answer» E. | |
| 43. |
A rectangular air – filled waveguide has a cross section of 4 × 10 Theminimum frequency which can propagation in the waveguide is |
| A. | 1.5 ghz |
| B. | 2.5 ghz |
| C. | 2.0 ghz |
| D. | 3.0 ghz |
| Answer» B. 2.5 ghz | |
| 44. |
When a λ/4 transmission line is used for impedance matching, then which of the following is valid? |
| A. | standing waves are present on the λ/4 transmission line |
| B. | no standing waves on the λ/4 transmission line |
| C. | standing waves are not present both on the feed line and the matching λ/4 line |
| D. | standing waves are present on both the feed line and the matching λ/4 line |
| Answer» B. no standing waves on the λ/4 transmission line | |
| 45. |
__________ system obtains information about a target by transmitting a signaland receiving the echo from the target. |
| A. | radar |
| B. | sonar |
| C. | radiometer |
| D. | none of the above |
| Answer» B. sonar | |
| 46. |
ency forthe dominant mode is |
| A. | 2.5 ghz |
| B. | 10 ghz |
| C. | 5 ghz |
| D. | 12.5 ghz |
| Answer» B. 10 ghz | |
| 47. |
A directional coupler with three or more holes is sometimes used in preference tothe two-hole couple |
| A. | because it is more efficient |
| B. | to increase coupling of signal |
| C. | to reduce spurious mode generation |
| D. | to increase the bandwidth of the system |
| Answer» D. to increase the bandwidth of the system | |
| 48. |
The phase velocity of an electrometric wave propagating in a hollow metallicrectangular waveguide in the TE10 mode is |
| A. | equal to its group velocity |
| B. | less than velocity of light in free space |
| C. | equal to velocity of light in free space |
| D. | greater than velocity of light in free space |
| Answer» D. greater than velocity of light in free space | |
| 49. |
The effective dielectric constant ∈r for a microstrip line: |
| A. | varies with frequency |
| B. | independent of frequency |
| C. | it is a constant for a certain material |
| D. | depends on the material used to make microstrip |
| Answer» C. it is a constant for a certain material | |
| 50. |
Input impedance of a shorted lossless line of length π/4 is |
| A. | zero |
| B. | infinity |
| C. | zo |
| D. | none of the above |
| Answer» D. none of the above | |