1.

In a klystron amplifier the input cavity is called

A. buncher B. catcher C. Pierce gun D. collector
2. In a circular waveguide the dominant mode is
A. TE01 B. TE11 C. TE20 D. TE21
3. Microwave resonators are used in
A. microwave oscillators B. microwave narrow band amplifier
C. microwave frequency metres D. all of the above
4. In a TWT the amplitude of resultant wave travelling down the helix
A. increases exponentially B. increases linearly
C. decreases exponentially D. is almost constant
5. Which of the following is not a travelling wave?
A. e = Em sin (βx - ωt) B. e = Em cos (βx - ωt)
C. e = Em sin (ωt - βx) D. e = Em sin (βx)
6. Both Impatt and Trapatt devices use avalanche effect (True / False)
7. In a directional coupler
A. isolation (dB) equals coupling plus directivity
B. coupling (dB) equals isolation plus directivity
C. directivity (dB) equals isolation plus coupling
D. isolation (dB) equals (coupling) (directivity)
8. As the frequency is increased, the charging MVAR in a cable
A. decreases B. increases
C. remain the same D. decreases or remains the scheme
9. In a three-cavity klystron amplifier, the oscillations are excited in
A. input cavity B. output cavity
C. intermediate cavity D. both (a) and (b)
10. Which of the following lines is non-radiating?
A. Open two wire B. Coaxial
C. Both D. None of the above
11. Skin effect is more pronounced at high frequencies. (True / False)
12. Which of the following devices uses a helix?
A. Klystron amplifier B. Klystron oscillator
C. TWT D. Both (a) and (b)
13. Which of the following parameters is negligible in transmission lines?
A. R B. L C. C D. G
14. The diagram to show distance time history of electrons in klystron amplifier is called
A. apple gate diagram B. asynchronous diagram
C. bunching diagram D. velocity modulation diagram
15. Impedance level of Impatt diodes is generally lower than that of Gunn diodes (True / False)
16. A quarter wave line open circuited at far end behaves as
A. inductance B. L and C in parallel
C. capacitance D. L and C in series
17. In a microstrip transmission the signal can be easily redirected by changing the centre strip.
(True / False)
18. The frequency of oscillation in a backward wave oscillator can be changed by
A. varying the voltage which controls beam velocity B. varying the beam current
C. both by varying the beam current and by light varying the voltage which controls beam velocity
D. changing the rate of thermionic emission
19. The fabrication of microstrip line is done by
A. photo etching B. printed circuit technique
C. oxidation D. cladding
20. the action of backward wave oscillator is similar to that of
A. klystron amplifier B. reflex klystron oscillator
C. TWT D. magnetron
21. Which TM mode in rectangular waveguide has lowest cutoff frequency?
A. TM11 B. TM01 C. TM10 D. TM21
22. Which of the following devices uses a slow wave structure?
A. Klystron two cavity amplifier B. Klystron multicavity amplifier
C. Reflex klystron oscillator D. TWT
23. A waveguide section in a microwave circuit acts as
A. LP filter B. Bandpass filter C. HP filter D. Band stop filter
24. Klystron operates on the principle of
A Velocity Modulation B Pulse Modulation
C Amplitude Modulation D none
25. fabrication of microstrip line is_____.
A cladding B printed circuit technique C oxidation D None of these
26. is the most common antenna to the predetermined radiation pattern.
A array antenna B helical antenna C sectrol horn D None of the above
27. is the main advantage of a microwave.
A Highly directive B High penetration power
C Moves at the speed of light D None of these
28. One of the following is used for amplification of microwave energy.
A magnetron B travelling wave tube C gunn diode D None of these
29. is depend on the velocity factor of a transmission line.
A relative permittivity of dielectric B impedance
C temperature D None of these
30. A Gunn diode is a negative resistance device, which is used as source of microwaves. What is the
number of p-n junctions?
A0 B3 C2 D1
31. The main disadvantage of using coaxial cable for microwave signals is its
A High attenuation B High sensitivity C Low distortion D Low selectivity
32. Which of the following is a circularly polarized antenna?
A Helical B Pyramidal C Horn D Dipole
33. Which one of the following is a transferred electron device?
A Gunn DIODE B TRAPATT diode C IMPATT diode D BARITT diode
34. 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
35. The major advantage of TWT over Klystron
(A) higher gain (B) higher frequency (C) higher output (D) higher bandwidth
36. Microwave antenna aperture efficiency depends on
(A) Feed Pattern (B) Antenna Aperture (C) Surface losses (D) Low side lobe level
37. 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
38. Which of the following can be used for amplification of microwave energy?
(A) Travelling wave tube (B) Magnetron
(C) Reflex Klystron (D) Gunn diode
39. 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
40. tunnel diode does nor exhibit
(A) positive resistance (B) negative resistance
(C) both (D) none of the above