Optical communication MCQ | Pdf

Hello Students, how are you all hope you all will be good, in this Page we have shared with you more than 30 Important MCQ on optical communication which is helpful for verious entrance examinations. This Optical communication mcq will help you enhance your performance in Entrance exams.

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Here are the Optical Communication MCQ 

1. Optical fibres use the phenomenon of_______

(a) Refraction

(b) Dispersion

(c) Total internal reflection 

(d) Scattering

Answer: C

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2. Audio signals cannot be transmitted directly over long distances because

(a) the Signal cannot be amplified for long distance communication

(b) the audio signals have more noise

(c) the size of the transmitting antenna will be very large and impractical

(d) the length of the transmitting antenna is very small.

Answer: C

3. If n, and n, are the refractive indices of the core and the cladding respectively of an optical fibre, then

(a) n1 = n2

(b) n1 > n2

(c) n1 < n2

(d) n1= 2n2

Answer: B

4. In modulation we______

(a) separate the audiofrequency signal from the carrier wave

(b) superimpose the audiofrequency signal over a carrier wave

(c) separate the carrier wave from the modulated wave

(d) increase the power of the audio frequency signal

Answer: B

5. Modern communication systems consists of_____

(a) electrical systemns

(b) elettronic systems

(c) all of the above

(d) optical systems

Answer: C

6. A communication system mainly consist of_____

(a) a transmitter and a receivern

(b) a transmitter and a communication channel

(c) a transmitter, a communication channel and a r├ęceiver

(d) a receiver and a communication channel

Answer: C

7. The messages fed to the transmitter are generally________

(a) Radio signals

b) Audio signals

(c) Both a & b

(d) optical signals 

Answer: B

8. The process of superimposing information signals on a carrier wave is called_____

(a) modulation

(b) demodulation

(c) detection

(d) multiplexing

Answer: A

9. The optical fibres are made from______

(a) semiconductors

(b) good conductors

(c) insulators

(d) ferromagnetic materials

Answer: C

10. How many TV signals can be transmitted by using an Optical fibre communication system, if the T.V. Signal require a band width of 2.5 MHz and the laser beam provides a channel band width of 5 x 10 Hz?

(a) one million

(b) two million

(c) 0.5 million

(d) 1.5 million

Answer  : B

11. In optical fibre communication system, light signals are converted into electrical signals by using______

(a) xener diodes

(b) forward biased p-n junction diodes

(c) photo diodes

(d) transistors

Answer: C

12. In the fabrication of optical fibres, powder of is used______

(a) Sio2

(b) MnO2

(c) CO2

(d) NaCl

Answer:  A

13. Carrier waves are generally_____

(a) low frequency waves

(b) high frequency waves

(c) medium frequency waves

(d) ultrasonic waves

Answer: B

14. Out of the following guided media, maximum bandwidth is obtained in the case of____

(a) telephone lines

(b) optical fibres

(c) aluminium cables

(d) twisted pair

Answer: B

15. Indicate the 'wrong' statement from the following: Modulation is used to____

(a) allow the use of practicable antenna

(b) ensure that the information is trasmitted over long distances

(c) increase the band widths

(d) decrease the band width

Answer: D

16. An optical fibre is made up of______

(a) glass

(b) copper

(c) plastic

(d) either (a) or (c) or (a) and (c)

Answer: D

17. Optical fibres are______

(a) good conductors

(b) insulators

(c) elastic materials

(d) Rigid materials

Answer: B

18. The process of changing some characteristics eional of is called a carrier wave in accordance with the incoming signal is called_____

(a) Amplification

(b) Rectification

(c) Modulation

(d) Demodulation

Answer: C

19. In optical fibre communication system, instead or electrical signals_____ Signals are used._____

(a) analog

(b) mechanical 

(c) light

(d) unmodulated

Answer : C

20. The diameter of a typical optical fibre is about 100 to 250______

(a) mm

(b) angstrom unit

(c) micrometer

(d) nanometer

Answer: C

21. Total intemal reflection takes place, when light travels from_____

(a) air to glass

(b) air to water

(c) water to glass

(d) glass to water

Answer: D

22. In an optical fibre, the refractive index of the core material is _____

(a) equal to R.I of the cladding material

(b) less than that of the cladding material

(c) more than that of the cladding material

(d) negligible as compared to that of the cladding material

Answer : C

23. If sound waves of frequency 20 KHz are to be transmitted.directly, then the length of the antenna required is

(a) 15 km

(b) 3.75 km

(c) 20 km

(d) 7.5 km

Answer: D

24. Optical fibre systems are particularly suitable for the.data such as that generated by transmission of computers______

(a) digital

(b) analog

(c) amplified

(d) modulated

Answer: A

25. Optical fibre communication is generally preferred over cable communication system because of_____

(a) low transmission loss 

(b) high degree of security

(c) their small size

(d) all the above

Answer : D

26. Optical fibres fabricated by using plastic core and lastic cladding_____

(a) have very low transmission losses

(b) have very hign transmission losses

(c) Have large bandwidth.

(d) All of the above.

Answer : B

27. Antennas are made from______

(a) insulators

(b) metallic conductors

(c) semiconductors

(d) super conductors

Answer: B

28. Which is the wrong statement from the following?

(a) Optical fibres may have a homogeneous core with suitable cladding

(b) Optical fibres can be of graded refractive index

(c) The only disadvantage of optical fibres is that they are subjected to electromagnetic interference from


(d) Optical fibres have an extremely small transmission loss

Answer: C

29. In optical fibre refractive index of core is

(a) less than R.I. of cladding

(b) more than R.I. of cladding ubere

(c) equal to R.I. of cladding

(d) halfed to R.I. of cladding

Answer : B