Modulation index of a amplitude modulated wave is 75%. If its maximum amplitude is 14 V. The amplitude of carrier wave is:

8 V

The correct answer is Option (1) → 8 V

The modulation index (m) is,

$m=\frac{A_m}{A_c}=\frac{A_{max}-A_{min}}{A_{max}+A_{min}}$

$⇒m=\frac{A_m}{A_c}$

$⇒A_m=A_c.m$

and,

$A_{max}=A_c+A_m$

$=A_c+m.A_c=A_c(1+m)$

$∴A_c=\frac{A_{max}}{1+m}=\frac{14}{1+0.75}=8V$