ADVANCE COMMUNICATION SYSYTEM MCQ-5

1. A passive Satellite :

(A) Amplifies the signal
(B) Reflects the signal
(C) Absorbs the signal
(D) None of the above

2. It the critical frequency of 30 MHz is departing at an angle of 60°, then MuF is :

(A) 15 MHz
(B) 30 MHz
(C) 60 MHz
(D) 10 MHz

3. In a RADAR system which of the following is used for transmitter output tubes?

(A) Magnetron
(B) Klystron
(C) TWT
(D) Any of the above

4. Cellular telephone services are also known as :

(A) AMPS
(B) MPS
(C) UPS
(D) None of these

5. Free space intrinsic impedance is :

(A) 120πΩ
(B) 377Ω
(C) Both (a) and (b)
(D) None of these

6. Which of the following expression is correct ?

(A) V_g.V_p=C²
(B) V_g.V_p=1
(C) V_g.V_p=C
(D) V_g.V_p=√2C

7. The signal at the output of an AM modulator is given by e_AM(t)=5.3[1+0.64Sin6280t] Sin10₆tV. The amplitude of carrier signal is :

(A) 5.3 V
(B) 3.39 V
(C) 6 V
(D) 10 V

8. A carrier is simultaneously modulated by two Sine waves with modulation index 0.3 and 0.4 the total modulation index is :

(A) 0.1
(B) 0.5
(C) 0.3
(D) 0.4

9. The distance of synchronous satellite from earth surface is :

(A) 3600 Km
(B) 50,000 Km
(C) 36,000 Km
(D) 40,000 Km

10. A magnetron is a :

(A) High power oscillator
(B) Low power oscillator
(C) Low power amplifier
(D) High power amplifier

11. A cavity can be considered as :

(A) B.P.F
(B) L.P.F
(C) H.P.F
(D) B.S.F

12. In a RADAR System PRF stands for :

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

13. Energy can be propagated in waveguide by :

(A) Varying voltage
(B) Varying current
(C) Varying electric and magnetic field
(D) None of the above

14. Which of the following exibits negative resistance :

(A) Tunnel diode
(B) Gunn diode
(C) Varactor diode
(D) Both (a) and (b)

15. Gauss’s laws of eletro statics is represented by the following expression :

(A) ∇.D=ρ
(B) ∇.B=O
(C) ∇x B= …B/…t
(D) ∇x H=Jε+(…D/…t)

16. What is the frequency range of C-band?

(A) 8.5 to 12.5 GHz
(B) 3.4 to 6.425 GHz
(C) 12.95 to 14.95 GHz
(D) 27.5 to 31 GHz

17. What is the reason for carrying multiple transponders in a satellite?

(A) More number of operating channel
(B) Better reception
(C) More gain
(D) Redundancy

18. Which technique uses two different antennas to reduce traffic on the same frequency?

(A) Spatial isolation
(B) Frequency reuse
(C) Multiplexing
(D) Modulation

19. What provides the sufficient drive to the final power amplifier?

(A) Intermediate-power amplifier
(B) Operational amplifier
(C) Power driver circuit
(D) Up converter

20. The lowest frequency used in satellite communications is ______ GHz.

(A) 0.8
(B) 3
(C) 18
(D) 30