In optical communication system operating at 1200nm, only 2% of the source frequency is available for TV t ransmission having a bandwidth of 5 MHz. the number of TV channels that can be transmitted is

Options

A. 2 million
B. 10 million
C. 0.1 million
D. 1 million

Answer

D

Explanation

Opitcal source frequency `v= (c)/(lambda) `
`implies v=( 3 xx 10^8 ms^(-1))/( 1200 xx 10^(-9) m ) = 2.5 xx 10^(14) Hz `
Bandwidth of channel ( 2% of the source of frequency )
`=5 xx 10^(12) Hz `
Number of channels `= (" Total bandwidth")/( "Bandwidth needed per channel")`
`=( 5 xx 10^(12) Hz)/( 5 xx 10^(16) Hz) = 10^(6) = 1 ` million.