Given the electric field of a complete amplitude modulated wave as $$ \vec{E}=\hat{i} E_c\left(1+\frac{E_m}{E_c} \cos \omega_m t\right) \cos \omega_c t $$ Where the subscript c stands for the carrier wave and $\mathrm{m}$ for the modulating signal. The frequencies present in the modulated wave are

• A

  $\omega_c$ and $\sqrt{\omega_c^2+\omega_m^2}$
• Correct answer
  B

  $\omega_c, \omega_c+\omega_m$ and $\omega_c-\omega_m$
• C

  $\omega_c$ and $\omega_m$
• D

  $\omega_c$ and $\sqrt{\omega_c \omega_m}$

Hence, the correct answer is option: 'B'.