The waves which are reflected back to the earth by the ionosphere are:

In an amplitude modulated signal,the maximum amplitude is $15 V$ and the minimum amplitude is $5 V$. The amplitude of the modulating wave will be (in $V$)

In amplitude modulation,

In satellite communication,the $6\,\text{GHz}$ frequency is used for........... and the $4\,\text{GHz}$ frequency is used for...........

In general,a transmitting antenna is........

Which waves can be transmitted more efficiently by an antenna?