JEE Main202229 Jun 2022Morning ShiftPhysicsCommunication SystemActual
Only 2 % of the optical source frequency is the available channel bandwidth for an optical communicating system operating at 1000 nm . If an audio signal requires a bandwidth of 8 kHz , how many channels can be accommodated for transmission
Options
- A375 × 10 7
- B75 × 10 7
- C375 × 10 8
- D75 × 10 9
Correct answer
B. 75 × 10 7
Step-by-step solution
Frequency f = c λ = 3 × 10 8 1000 × 10 - 9 = 3 × 10 14   Hz Band width used for transmission = 2 100 × 3 × 10 14   Hz = 6 × 10 12   Hz Number of channels N = Total bandwidth of channel   Bandwidth needed per channel   = 6 × 10 12 8 × 10 3 = 600 8 × 10 7 = 75 × 10 7