Question

A carrier of peak voltage 15 V is used to transmit a message signal. If the modulation index is 70%, then what will be the peak voltage of the modulating signal?

(a) 25 V

(b) 11 V

(c) 10.5 V

(d) 30 V

I had been asked this question in a national level competition.

This intriguing question comes from Communication Systems topic in chapter Communication Systems of Physics – Class 12

Answer 1

The correct option is (c) 10.5 V

To explain: μ = \(\frac {A_m}{A_c}\).

Am = μ × Ac.

Am = \( ( \frac {70}{100})\) × 15 V

Am = 10.5 V.