AP EAMCET Engineering 2018 Apr 22 Shift 1 Paper

The expression for modulation index is,
M=Vpeak,signalVpeak,carrier
Substitute the value in above expression.
0.6=

12

V ‌peak.carrior

Vpeak,carrior=20V
The modulation index in 2nd case is given as,
0.75=

12

(Vpeak,carrior)1

(Vpeak.carrior)1=16V
The change in peak voltage is given as,
ΔV=20V−16V=4V
The percentage change is given as,
=

4

20

×100%=20%