microwave engineering objective questions and answers part2

Q1. In Microwave we consider the elements as
(A) Lumped circuit elements
(B) Distributed circuit elements
(C) Both are correct
(D) None of these

Q2. The major advantage of TWT over Klystron
(A) higher gain
(B) higher frequency
(C) higher output
(D) higher bandwidth

Q3. Travelling wave parametric amplifiers are used to
(A) provide a greater gain
(B) reduce the number of varactor diodes required
(C) avoid the need for cooling
(D) provide a greater bandwidth

Q4. For best low-level noise performance in the X-band an amplifier should use
(A) A bipolar transistor
(B) A Gunn diode
(C) A step recovery diode
(D) An IMPATT diode

Q5. For Gunn diodes, gallium arsenide is preferred to silicon because the former
(A) Has a suitable empty energy band, which silicon does not have
(B) Has a higher ion mobility
(C) Has a lower noise at the highest frequencies
(D) Is capable of handling higher power densities

Q6. Microwave antenna aperture efficiency depends on
(A) Feed Pattern
(B) Antenna Aperture
(C) Surface losses
(D) Low side lobe level

Q7. The negative resistance in a tunnel diode
(A) is maximum at the peak point of the characteristic
(B) is available between the peak and valley points
(C) is maximum at valley point
(D) may be improved by the use of reverse bias

Q8. A varactor diode may not be useful at microwave frequencies
(A) For electronic tuning
(B) for frequency multiplication
(C) as an oscillator
(D) As a parametric amplifier

Q9. The biggest advantage of the TRAPATT diode over the IMPATT diode is its
(A) Low noise
(B) Higher efficiency
(C) Ability to operate at higher frequencies
(D) Lesser sensitivity to harmonics

Q10. In mode operation of magnetron, the spokes due to phase focusing effect rotate at an angular velocity corresponding to
(A) One pole/cycle
(B) Two poles/cycle
(C) Four poles/cycle
(D) Six poles/cycle

Q11. In microwave power measurements using bolometer, the principle of working is the variation of
(A) Inductance with absorption of power
(B) Resistance with absorption of power
(C) Capacitance with absorption of power
(D) Cavity dimensions with heat generated by the power

Q12. Which of the following can be used for amplification of microwave energy?
(A) Travelling wave tube
(B) Magnetron
(C) Reflex Klystron
(D) Gunn diode

Q13. A magic-Tee is
(A) A modification of E-plane tee
(B) A modification of H-plane tee
(C) A combination of E-Plane and H-Plane
(D) Two E-plane tees connected in parallel

Q14. Klystron operates on the principle of
(A) Amplitude Modulation
(B) Frequency Modulation
(C) Pulse Modulation
(D) Velocity Modulation

Q15. The modes in a reflex Klystron
(A) give the same frequency but different transit times
(B) result from excessive transit time across the resonator gap
(C) are caused by spurious frequency modulation
(D) are just for theoretical considerations

Q16. tunnel diode does nor exhibit
(A) positive resistance
(B) negative resistance
(C) both
(D) none of the above

Q17. Full form of SONAR
(A) sound navigate resonance
(B) sound near rectification
(C) Sound Navigation and ranging
(D) sound navigate resistance

Q18. The microwave range is
(A) 30MHz - 300MHz
(B) 300MHz - 3GHz
(C) 3GHz-30GHz
(D) 30GHz-300GHz

Q19. IRIS is used to overcome
(A) power loss
(B) mismatch error
(C) twist effect
(D) bending effect

Q20. At microwave frequencies, the size of antenna becomes
(A) very large
(B) large
(C) small
(D) very small