০০। A 20 m antenna gives a certain uplink gain at frequencies of 4/6 GHz. For getting same gain in the 20/30 GHz band, antenna size required is metre.
ক) 100
খ) 4
গ) 1
ঘ) 10
০১। A certain sound has 10000 times more energy than another sound. The number of times it would sound stronger to a listener is
ক) 40
খ) 10000
গ) 100
ঘ) 10
০২। A colour television signal having bandwidth of 4.6 MHz is digitised using 10 bits sample. The digital bit rate used for its transmission with PCM would be __________ kilobits/second.
ক) 92000
খ) 920
গ) 23000
ঘ) 230
০৩। A communication satellite is a repeater between
ক) a transmitting station and a receiving station
খ) a transmitting station and many receiving station
গ) many transmitting station and many receiving station
ঘ) none
০৪। A few minutes disturbance in space communications occurs twice a year during Sunblinding when __________ are in line.
ক) Sun and satellite
খ) Sun and Earth station
গ) Satellite and Earth station
ঘ) Sun, satellite and Earth station
০৫। A geostationary satellite is one which
ক) hangs motionless in space about 36000 km about Earth
খ) travels around the Earth in 24 hours
গ) remains stationary above the Earth
ঘ) appears stationary to everybody on Earth
০৬। A geosynchronous satellite
ক) has the same period a that of the Earth
খ) has a circular orbit
গ) rotates in the equatorial plane
ঘ) has all of the above
০৭। A modem is
ক) a form of commutator
খ) a device for digitizing speech
গ) a circuit used for suppressing microwave mterference
ঘ) an electronic circuit which carries out modulation and demodulation of a carrier frequency
০৮। A satellite link uses different frequencies for receiving and transmitting in order to
ক) avoid interference from terrestrial microwave links
খ) avoid interference between its powerful transmitted signal and weak in coming signal
গ) minimise free-space losses
ঘ) maximise antenna gain
০৯। A telephone user while talking to a person via a satellite has to wait for reply for about __________ millisecond.
ক) 100
খ) 270
গ) 470
ঘ) 540
১০। A transponder is a satellite equipment which
ক) receives a signal from Earth station and amplifies
খ) changes the frequency of the received signal
গ) retransmits the received signal
ঘ) does all of the above-mentioned functions
১১। A typical error rate on satellite circuits is one bit error in
ক) 107
খ) 103
গ) 102
ঘ) 1010
১২। A typical signal strength received from a geosynchronous communication satellite is of the order of a few
ক) milliwatts
খ) kilowatts
গ) picowatts
ঘ) watts
১৩। After the death of INSAT-IB, the mainstay of the entire Indian satellite network for some time to come would be
ক) INSTELSAT-V
খ) INSAT-ID
গ) INSAT-2
ঘ) ARABSAT
১৪। APPLE was into orbit on 19 th June 1981 by European Space Agency (ESA) from
ক) Cape Canaveral in Florida
খ) Kourou in French Guyana
গ) Canarvon in Western Australia
ঘ) Bangalore in South India
১৫। As compared to 17.34° antenna, the total increase in the signal relayed by 4.5° antenna of INTELSAT-IV is
ক) 14.85
খ) 220
গ) 78
ঘ) 3.85
১৬। Assuming a minimum angle of elevation of 5°, a geosynchronous satellite remains in line-of-sight for __________ percentage of Earth's surface.
ক) 30.3
খ) 42.4
গ) 50
ঘ) 25
১৭। Assuming earth to be a sphere of radius 6400 km and height of a geosynchronous satellite above Earth as 36000 km, the velocity of a geosynchronous satellite is __________ km/hr.
ক) 28000
খ) 15000
গ) 36000
ঘ) 11100
১৮। At present, the radio-frequency band mainly used by most satellites is
ক) EHF
খ) UHF
গ) VHF
ঘ) SHF
১৯। Depending on the technique used, digitized television requires a bit rate between __________ millions.