IB question set 5

IB Examination 2013 Name of the Examination: Assistant Central Intelligence Officer Grade -II (Technical & Wireless Telegraphy) Examination -2013 Total Marks : 100 Date of Examination : 24/03/2013(March 24, 2013) Question No 41 to 50 (part 5)
Instructions : 1. Each question is followed by four alternatives (i), (ii), (iii) and (iv). Only one alternative is the correct answer, which should be marked by darkening the circle completely with BLUE BALLPOINT PEN only OMR response sheet provided separately. 2. Rough work, if any may be done on the question paper and at all on the OMR response sheet.
41. In a broadcast superhetrodyne receiver, i) local oscillator operates below the signal frequency ii) RF amplifier normally works at 455 KHz above the carrier frequency iii)local oscillator frequency is normally double the IF iv) mixer input must be tuned to the signal frequency
42. A superhetrodyne receiver with an IF of 450KHz is tuned to a signal at 1200 KHz. The image frequency is i) 750 KHz ii) 900 KHz iii) 1650 KHz iv) 2100 KHz
43. A typical squelch circuit i) cuts off an audio amplifier when the carrier is absent ii) eliminates the RF interference when the signal is weak iii) cuts off an IF amplifier when the AGC is maximum iv) cuts off an IF amplifier when the AGC is minimum
44. As electromagnetic waves travel in free space, only one of the following can happen to them i) absorption ii) attenution iii) refraction iv) reflection
45. Fleming's Left Hand Rule can be used to determine i) the magnitude of force experienced by a current carrying conductor placed in a magnetic field ii)the direction of magnetic field intensity (H) at any point due to a current carrying conductor iii) the direction of force experienced by a current carrying conductor placed in a magnetic field iv) None of these
46. The wavelength (λ) is meters of an electromagnetic wave is related to its frequency (f) in Hz by i) λ=(3x108)/f ii) λ=(3x1010)/f iii) λ=(300)/f iv) none of these
47. An FM signal contains intelligence in i) its frequency variation ii) its frequency and time variation iii) its amplitude variation iv) none of these
48. What type of functional block could possibly be implemented by a frequency to voltage converter i) frequency modulator ii) FM detector iii) AM demodulator iv) none of these
49. Optical communication uses the frequency range of i) 109 to 1010 Hz ii) 105 to 106 Hz iii) 1014 to 1015 Hz iv) 1016 to 1017 Hz
50. Optical fiber rely for their operation on the phenomenon of i) reflection ii) total internal reflection iii) refraction iv) dispersion

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