Sunday, 28 September 2014

COMMUNICATIONS GRADE 12 MCQ QUESTIONS


1. Indicate which one of the following system is digital

2. Basically, the product modulator is

3. The maximum distance upto which TV transmission from a TV tower of height h can be received is proportional to . [AIIMS 2003]


4. Advantage of optical fibre . [DCE 2005]

5. Laser beams are used to measure long distances because . [DCE 2002, 03]
6. Range of frequencies allotted for commercial FM radio broadcast is . [MNR 1997]


7. The phenomenon by which light travels in an optical fibres is . [DCE 2001]


8. Consider telecommunication through optical fibres. Which of the following statements is not true . [AIEEE 2003]

9. In which of the following remote sensing technique is not used . [Kerala PMT 2005]

10. What is the modulation index of an over modulated wave


11. An antenna is a device


12. Which of the following is the disadvantage of FM over AM

13. For sky wave propagation of a 10 MHz signal, what should be the minimum electron density in ionosphere .[AIIMS 2005]

14. The process of superimposing signal frequency (i.e. audio wave) on the carrier wave is known as . [AIIMS 1987]

15. In an amplitude modulated wave for audio frequency of 500 cycle/second, the appropriate carrier frequency will be . [AMU 1996]
16. In short wave communication waves of which of the following frequencies will be reflected back by the ionospheric layer, having electron density 1011 per m3 . [AIIMS 2003]

17. For television broadcasting, the frequency employed is normally . [AMU 2002]

18. Through which mode of propagation, the radio waves can be sent from one place to another . [JIPMER 2003]


19. A laser beam is used for carrying out surgery because it . [AIIMS 2003]

20. The waves used in telecommunication are
21. Audio signal cannot be transmitted because . [Kerala PMT 2005]

22. A step index fibre has a relative refractive index of 0.88%. What is the critical angle at the corecladding interface . [Manipal 2003]

23. Television signals on earth cannot be received at distances greater than 100 km from the transmission station. The reason behind this is that . [DCE 1995]


24. In frequency modulation . [Kerala PMT 2005]

25. In an FM system a 7 kHz signal modulates 108 MHz carrier so that frequency deviation is 50 kHz. The carrier swing is