260. The radius of the Earth is
A. 2000 km
B. 4000 km
C. 6372 km
D. 8640 km

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261.  The orbital period of a satellite is proportional to
A.r
B. r2
C. r3/2
D. r

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262. For a satellite with time period of 2 hours, the height above the surface must be
A. 500 km
B. 10001cm
C. 2000 km
D.3000 km

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263. Moon completes one orbit in
A. 24 hours
B. 3 days
C. 24 days
D. 28 days

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264.  Long distance communication system via satellite uses frequency in the range
A. 1 to 2.5 MHz
B. 3 to 6 GHz
C. 50 to 100 GHz
D. 200 to 400 GHz

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265. A system has poles at 0.01 Hz, 1 Hz and 80 Hz; zeros at 5 Hz and 200 Hz. The approximate phase of the system response at 20 Hz is
A. -90?
B. 0?
C. 90?
D. -180?

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266. A mW video signal having a bandwidth of 100 MHz is transmitted to a received through a cable that has 40 dB loss, lithe effective one-sided noise spectral density at the receiver is 10-20 Watt/Hz, then the signal-to-noise ratio at the receiver is
A. 50 dB
B. 30 dB
C. 40 dB
D. 60 dB

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