MCQOPTIONS
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MCQOPTIONS
This section includes 149 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
The ending part of the popular teleserial Mahabharat will be beamed to the viewers |
| A. | WESTAT |
| B. | INSAT-IC |
| C. | ARABSAT |
| D. | INSAT-ID |
| Answer» D. INSAT-ID | |
| 102. |
Power received from Sun per m2 surface area of a geosynchronous satellite in nearly __________ watt. |
| A. | 100 |
| B. | 500 |
| C. | 2000 |
| D. | 1000 |
| Answer» E. | |
| 103. |
Which one of the following statements regarding compandor is FALSE? |
| A. | It compresses the higher-amplitude parts of a signal before modulation and expands them back to normal again after demodulation. |
| B. | It gives preferential treatment to the weaker parts of the signal |
| C. | For weaker signals it gives a poor ratio of signal strength to quantizing error |
| D. | Weaker signals, traverse more quantum steps than they would do otherwise and so quantizing error is reduced. |
| Answer» D. Weaker signals, traverse more quantum steps than they would do otherwise and so quantizing error is reduced. | |
| 104. |
Satellite launch sites are invariably located on Eastern seaboards to ensure that |
| A. | launch takes place eastward |
| B. | expenditure of propulsion fuel is reduced during plane changing |
| C. | the satellite achieves circular orbit quickly |
| D. | spent rocket motor and other launcher debris falls into the sea |
| Answer» E. | |
| 105. |
A modem is |
| A. | a form of commutator |
| B. | a device for digitizing speech |
| C. | a circuit used for suppressing microwave mterference |
| D. | an electronic circuit which carries out modulation and demodulation of a carrier frequency |
| Answer» E. | |
| 106. |
In the context of error detection in satellite transmission, ARQ stands for |
| A. | Automatic Repeat Request |
| B. | Automatic Relay Request |
| C. | Accelerated Recovery Request |
| D. | Automatic Radiation Quenching |
| Answer» B. Automatic Relay Request | |
| 107. |
In satellite communication, frequency modulation is used because satellite channel has |
| A. | small bandwidth and negligible noise |
| B. | large bandwidth and severe noise |
| C. | maximum bandwidth and minimum noise |
| D. | high modulation index |
| Answer» C. maximum bandwidth and minimum noise | |
| 108. |
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. |
| A. | 92000 |
| B. | 920 |
| C. | 23000 |
| D. | 230 |
| Answer» B. 920 | |
| 109. |
The useful operational life of INSAT-IB (launched in 1983) is expected to end by |
| A. | 1992-93 |
| B. | 1991-92 |
| C. | 1989-90 |
| D. | 1993-94 |
| Answer» D. 1993-94 | |
| 110. |
The INTELSAT-IV satellite launched in 1974 had two earth coverage antenna and two narrower-angle antennas subtending 4.5°. The signal from narrow-angle antenna was stronger than that from earth- coverage antenna by a factor of |
| A. | 17.34/4.5 |
| B. | 17.34 x 4.5 |
| C. | (17.34/4.5)2 |
| D. | (17.34/4.5)4 |
| Answer» D. (17.34/4.5)4 | |
| 111. |
As compared to 17.34° antenna, the total increase in the signal relayed by 4.5° antenna of INTELSAT-IV is |
| A. | 14.85 |
| B. | 220 |
| C. | 78 |
| D. | 3.85 |
| Answer» C. 78 | |
| 112. |
A geostationary satellite is one which |
| A. | hangs motionless in space about 36000 km about Earth |
| B. | travels around the Earth in 24 hours |
| C. | remains stationary above the Earth |
| D. | appears stationary to everybody on Earth |
| Answer» E. | |
| 113. |
Radio broadcasting is a familiar example of |
| A. | space multiplexing |
| B. | time multiplexing |
| C. | frequency multiplexing |
| D. | none of the above |
| Answer» D. none of the above | |
| 114. |
When a communication satellite passes into Earth's shadow, its temperature drops to about __________ ° K. |
| A. | 273 |
| B. | 243 |
| C. | 170 |
| D. | 123 |
| Answer» E. | |
| 115. |
The degradation of satellite solar cells with time is mainly due to |
| A. | their bombardment by electrons |
| B. | collection of meteoric dust |
| C. | increase in resistivity of silicon |
| D. | gradual leakage of charge carriers from the semiconductor material |
| Answer» B. collection of meteoric dust | |
| 116. |
A certain sound has 10000 times more energy than another sound. The number of times it would sound stronger to a listener is |
| A. | 40 |
| B. | 10000 |
| C. | 100 |
| D. | 10 |
| Answer» B. 10000 | |
| 117. |
The owner of a communication satellite is usually required to keep the spacecraft on station at its assigned place in the geosynchronous orbit with an accuracy of __________ degree. |
| A. | 0.1 |
| B. | 1 |
| C. | 2 |
| D. | 0.5 |
| Answer» B. 1 | |
| 118. |
A geosynchronous satellite |
| A. | has the same period a that of the Earth |
| B. | has a circular orbit |
| C. | rotates in the equatorial plane |
| D. | has all of the above |
| Answer» E. | |
| 119. |
For satellite communication, standard Earth stations have antenna diameters in the range of __________ metre. |
| A. | 27.5 to 30 |
| B. | 10 to 15 |
| C. | 30 to 50 |
| D. | 5 to 10 |
| Answer» B. 10 to 15 | |
| 120. |
In communication satellites, the up-link normally operates at a higher frequency than the down-link because it |
| A. | gives a narrow beam shining into space |
| B. | results in lesser signal attenuation |
| C. | gives better beam-shaping |
| D. | is easier to polarize a high frequency beam |
| Answer» B. results in lesser signal attenuation | |
| 121. |
The different access methods which permit many satellite users to operate in parallel through a single transponder without interfering with each other as |
| A. | Frequency Division Multiple Access (FDMA) |
| B. | Time Division Multiple Access (TDMA) |
| C. | Code Division Multiple Access (CDMA) |
| D. | All of the above |
| Answer» E. | |
| 122. |
Which one of the following statements regarding DSI is wrong? |
| A. | It is a digital form of TASI |
| B. | Though it is more efficient than TASI, it is much slower |
| C. | A speaker has to wait (it at all) for only a few milliseconds for reallocation of channel |
| D. | It has increased the capacity of satellite channels by a factor of 2.2 or more with out degrading speech quality |
| Answer» C. A speaker has to wait (it at all) for only a few milliseconds for reallocation of channel | |
| 123. |
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. |
| A. | 28000 |
| B. | 15000 |
| C. | 36000 |
| D. | 11100 |
| Answer» E. | |
| 124. |
Depending on the technique used, digitized television requires a bit rate between __________ millions. |
| A. | 40 and 92.5 |
| B. | 25 and 60 |
| C. | 30 and 82.5 |
| D. | 2 |
| Answer» B. 25 and 60 | |
| 125. |
After the death of INSAT-IB, the mainstay of the entire Indian satellite network for some time to come would be |
| A. | INSTELSAT-V |
| B. | INSAT-ID |
| C. | INSAT-2 |
| D. | ARABSAT |
| Answer» E. | |
| 126. |
Which of the following factor does NOT contribute to the drift of a geostationary satellite from its stationary position in space? |
| A. | Pressure of solar radiations |
| B. | Gravitational changes due to Sun and Moon |
| C. | Oblateness of the Earth |
| D. | Weight of the satellite |
| Answer» E. | |
| 127. |
Which one of the following statement is correct? |
| A. | Satellite spacing is not affected by the bandwidth of the transmitting earth station |
| B. | Beamwidth is independent of antenna size and frequency band used |
| C. | The width of a beam in space is inversely proportional to the width of the transmitting antenna |
| D. | Use of high-frequency bands permits less number of satellites to share the orbit |
| Answer» D. Use of high-frequency bands permits less number of satellites to share the orbit | |
| 128. |
The geostationary communication satellite APPLE is parked in the equatorial orbit at |
| A. | 102° E longitude over Sumatra |
| B. | 90° E longitude over Bangladesh |
| C. | 74° E longitude over India |
| D. | 67° E longitude over Pakistan |
| Answer» B. 90¬∞ E longitude over Bangladesh | |
| 129. |
In the case of a 70-MHz IF carrier for a transponder bandwidth of 36 MHz, energy must lie between MHz. |
| A. | 34 and 106 |
| B. | 52 and 88 |
| C. | 106 and 142 |
| D. | 34 and 142 |
| Answer» C. 106 and 142 | |
| 130. |
A communication satellite is a repeater between |
| A. | a transmitting station and a receiving station |
| B. | a transmitting station and many receiving station |
| C. | many transmitting station and many receiving station |
| D. | none |
| Answer» D. none | |
| 131. |
Mark out the WRONG statement.As compared to FDMA, the demand assignment system TDMA |
| A. | Needs very high-speed burst modems |
| B. | Faces no problems caused by intermodulation of carriers so that transponder can be used at its full power |
| C. | Needs high-speed manipulation of bit streams |
| D. | Is less flexible so that channels of widely different capacities cannot used and intermixed |
| Answer» E. | |
| 132. |
A typical error rate on satellite circuits is one bit error in |
| A. | 107 |
| B. | 103 |
| C. | 102 |
| D. | 1010 |
| Answer» B. 103 | |
| 133. |
To cover all inhabited regions of the Earth, the number of geosynchronous communication satellites required |
| A. | 5 |
| B. | 3 |
| C. | 10 |
| D. | 2 |
| Answer» C. 10 | |
| 134. |
India's first domestic geostationary satellite 1NSAT-IA was launched on 10th April 1982 from |
| A. | USSR |
| B. | USA |
| C. | UK |
| D. | UP |
| Answer» C. UK | |
| 135. |
The most effective anti jamming technique is |
| A. | frequency hopping |
| B. | spread-spectrum modulation |
| C. | key leverage |
| D. | once-only key |
| Answer» C. key leverage | |
| 136. |
Orbital disturbances of a geosynchronous satellite are caused by the |
| A. | moon |
| B. | sun |
| C. | earth |
| D. | all of the above |
| Answer» E. | |
| 137. |
The quality of a space-link is measured in terms of the __________ ratio. |
| A. | C/N |
| B. | S/N |
| C. | G/T |
| D. | EIRP |
| Answer» B. S/N | |
| 138. |
For global communication, the number of satellites needed is |
| A. | 1 |
| B. | 3 |
| C. | 10 |
| D. | 5 |
| Answer» C. 10 | |
| 139. |
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. |
| A. | 100 |
| B. | 4 |
| C. | 1 |
| D. | 10 |
| Answer» C. 1 | |
| 140. |
Of the four INSAT-I satellites planned by India so for, only __________ has proved to be successful. |
| A. | INSAT-IA |
| B. | INSAT-IB |
| C. | INSAT-IC |
| D. | INSAT-ID |
| Answer» C. INSAT-IC | |
| 141. |
Noise temperature of Sun is more than __________ °K. |
| A. | 1000 |
| B. | 5000 |
| C. | 100000 |
| D. | 500 |
| Answer» D. 500 | |
| 142. |
The Sun blots out the transmission of a geosynchronous satellite twice a year when satellite passes directly in front of it. This outage lasts for about |
| A. | 10 minutes on 5 consecutive days |
| B. | 5 minutes on 10 consecutive days |
| C. | 30 minutes for 5 consecutive days |
| D. | one hour for 5 consecutive days |
| Answer» B. 5 minutes on 10 consecutive days | |
| 143. |
To make antenna more directional, either its size must be increased or |
| A. | the number of its feed horns must be increased |
| B. | the frequency of its transmission must be increased |
| C. | its effective isotropic radiated power (EIRP) must be increased |
| D. | its footprint must be increased |
| Answer» C. its effective isotropic radiated power (EIRP) must be increased | |
| 144. |
The noise temperature of sky is about __________ °K. |
| A. | 100 |
| B. | 273 |
| C. | 0 |
| D. | 30 |
| Answer» E. | |
| 145. |
While keeping the down-link frequency constant, the diameter of a satellite antenna is reduced by half. To offer the same EIRP over the increased coverage area, the RF output power has to be increases by a factor of |
| A. | 2 |
| B. | 4 |
| C. | 8 |
| D. | 16 |
| Answer» C. 8 | |
| 146. |
Rotation of a geosynchronous satellite means its |
| A. | drift from stationary position |
| B. | wobbling |
| C. | three-axis stabilization |
| D. | three-dimensional stabilization |
| Answer» C. three-axis stabilization | |
| 147. |
The discussing sharing of a communication satellite by many geographically dispersed Earth station, DAMA means |
| A. | Demand-Assigned Multiple Access |
| B. | Decibel Attenuated Microwave Access |
| C. | Digital Analog Master Antenna |
| D. | Dynamically-Assigned Multiple Access |
| Answer» B. Decibel Attenuated Microwave Access | |
| 148. |
In a stop-and-wait ARQ system, the transmitting terminal |
| A. | waits for positive or negative acknowled-gement from the receiving terminal after sending a block |
| B. | sends another block if positive acknowledge is received through ACK character |
| C. | resends the previous block if negative acknowledgement is received through a NAK character |
| D. | does not wait for acknowledgement after sending a block |
| Answer» E. | |
| 149. |
The first geostationary satellite launched in 1965 was called |
| A. | ANIK |
| B. | EARLY BIRD (Intelsat-I) |
| C. | WESTAR |
| D. | MOLNIYA |
| Answer» C. WESTAR | |