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NTA Abhyas 2020
Exam
NTA Abhyas
Year
2020
Subject
Physics
Chapter
Communication System

NTA Abhyas 2020 · Physics · Communication System

In optical communication systems operating at 1200nm , only 2 % of...

In optical communication systems operating at 1200nm1200nm, only 22 % of the source frequency is available for TV transmission having a bandwidth of 5MHz5MHz. The number of TV channels that can be transmitted is 10n{10}^{n}. The value of nn is

Correct answer

6

Step-by-step solution

The frequency of optical communication is given by,

v=cλorv = \dfrac{c}{\lambda} orv = \dfrac{3 \times {10}^{8}}{1200 \times {10}^{- 9}}<br/><br/><br /><br />v = 25 \times {10}^{13}Hz<br/><br/>Butonly<br /><br />But only2 %ofthesourcefrequencyisavailableforTVtransmission.<br/><br/>of the source frequency is available for TV transmission.<br /><br />{v}^{′} = 2 .5 \times {10}^{14} \times 2%<br/><br/><br /><br />{v}^{′} = 2 .5 \times {10}^{14} \times \dfrac{2}{100}<br/><br/><br /><br />{v}^{′} = 5 \times {10}^{12}Hz<br/><br/><br /><br />∴ Numberofchannels = \dfrac{{v}^{′}}{bandwidth}<br/><br/>Noofchannels=5×10125×106=106<br /><br />Noofchannels = \dfrac{{5 \times 10}^{12}}{{5 \times 10}^{6}} = {10}^{6}
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