ADVANCE COMMUNICATION SYSYTEM MCQ-1

1. For long distance communication via satellite the frequency ranges from

(A) 5 to 10 GHz
(B) 15 to 20 GHz
(C) 1 to 2 GHz
(D) 10 to 15 GHz

2. The instrument used for measurement of height for an aircraft is

(A) Radar altimeter
(B) Radar speedometer
(C) Radar elevator
(D) None of the above

3. The range of mobile telephone is about :

(A) 50 Km
(B) 30 Km
(C) 40 Km
(D) 10 Km

4. RADAR consist of :

(A) Antenna
(B) Transmitter
(C) Receiver
(D) All of the above

5. Radio waves have _____ frequency than microwave.

(A) Smaller
(B) Larger
(C) Very large
(D) None of the above

6. Ducting is caused due to _____ in version.

(A) Phase
(B) Temperature
(C) Phase/temperature
(D) None of these

7. What is the number of satellite required for global communication ?

(A) 1
(B) 2
(C) 3
(D) 4

8. Higher the frequency :

(A) Lower is the skip distance
(B) Skip distance does not change
(C) Higher is the skip distance
(D) None of the above

9. Synchronous satellite orbits the earth once in :

(A) 8 hr
(B) 12 hr
(C) 24 hr
(D) 1 hr

10. An electronic calculator uses :

(A) Pencil cells
(B) Solar cells
(C) Both (a) and (b)
(D) None of the above

11. Geostationary satellites follow :

(A) Elliptical path
(B) Circular path
(C) Inclined elliptical path
(D) None of the above

12. A duplexer is a :

(A) Single side band filter
(B) Transmitter-receiver
(C) Balanced mixer
(D) RF amplifier

13. In an AM wave, A_min=40V, A_max=60V, then modulation index is :

(A) 0.3
(B) 0.2
(C) 0.4
(D) 0.5

14. PRF stands for :

(A) Power return factor
(B) Pulse return factor
(C) Pulse repetation frequency
(D) Pulse response frequency

15. If E_m=peak value of information signal, E_c=peak value of carrier signal, then modulation index(m) is given by :

(A) m = E_c/E_m
(B) m = E_c.E_m
(C) m = E_c+E_m
(D) m = E_m/E_c

16. Sky waves are _____

(A) Horizontally polarized
(B) Vertically polarized
(C) Reflected from ionosphere
(D) Both (b) and (c)

17. Space waves are :

(A) Horizontally polarized
(B) Vertically polarized
(C) Reflected from ionosphere
(D) Refracted from ionosphere

18. FM broadcast lies in _____

(A) VHF band
(B) UHF band
(C) SHF band
(D) HF band

19. The maximum usable frequency and critical frequency are related as :

(A) muf = fc cos θ
(B) muf = fc sec θ
(C) muf = fc sin θ
(D) muf = fc cosec θ

20. The height of troposphere from the ground is nearly :

(A) 50 km
(B) 30 km
(C) 15 km
(D) 100 km