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For proper demodulation of an AM wave having carrier frequency f, which condition should the time constant RC satisfy?

1. RC = 1/f
2. RC < 1/f
3. RC 1/f
4. RC >> 1/f

Correct answer: RC >> 1/f

Solution

The time constant RC must be much greater than the inverse of the carrier frequency (1/f) to ensure that the demodulator can effectively follow the variations in the amplitude of the AM signal, allowing for accurate recovery of the original audio or information signal.

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