141. 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

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142. Nutation of a geosynchronous satellite means its
A. drift from stationary position
B. wobbling
C. three-axis stabilization
D. three-dimensional stabilization

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143. When a communication satellite passes into Earth's shadow, its temperature drops to about oK
A.273
B.243
C.170
D.123

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144. A typical signal strength received from a geosynchronous communication satellite is of the order of a few
A. milliwatts
B. kilowatts
C. picowatts
D. watts

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145. A certain sound has 10,000 times more energy than another sound. The number of times it would sound stronger to a listen& is
A.40
B.10,000
C.100
D.10

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146. 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

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147. Which of the following statement regarding link loss fur_ a satellite link is wrong?
A. for fixed antenna size, it is inversely proportional to f2
B.for fixed frequency, it is inversely proportional to the product of the antenna aperture are as
C. for a given satellite operating at a given frequency, it is inversely proportional to area of the earth station antenna
D. loss in down link is negligible as compared to that in uplink

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