**An audio signal υ _{m} = 20sin2π(1500t) amplitude modulates a carrier υ_{c} =80 sin 2π (100,000t). The value of percent modulation is ________.**

**Correct answer is 25 **

\(v_m = 20 sin [100\pi t+{\pi\over4}] \)

\(:v_c = 80 sin [10^4\pi t+{\pi\over6}] \)

we know that, modulation index =\(A_m\over A_c\)

from given equations, A_{m} = 20 and A_{c} = 80

percentage modulation index =\({A_m\over A_c}\times 100\)

= \(20\over80\) × 100 = 25%

**The value of percentage modulation index is =25**