question_answer

Given the electric field of a complete amplitude modulated wave as\[\overset{_{\to }}{\mathop{E}}\,=\hat{i}{{E}_{C}}\left( 1+\frac{{{E}_{m}}}{{{E}_{C}}}\cos {{\omega }_{m}}t \right)\cos {{\omega }_{C}}t.\] Where the subscript c stands for the carrier wave and m for the modulating signal. The frequencies present in the modulated wave are     JEE Main  Online Paper (Held On 19  May  2012)

A) \[{{\omega }_{C}}\]and\[\sqrt{\omega _{c}^{2}+\omega _{m}^{2}}\]

B)                        \[{{\omega }_{c}},{{\omega }_{c}}+{{\omega }_{m}}\] and\[{{\omega }_{c}}-{{\omega }_{m}}\]

C)                        \[{{\omega }_{c}}\]and\[{{\omega }_{m}}\]                       

D)                        \[{{\omega }_{c}}\]and\[\sqrt{{{\omega }_{c}}{{\omega }_{m}}}\]