The frequency of a $FM$ transmitter without signal input is called

Which of the following four alternatives is not correct? We need modulation:

The transmission of $UHF$ range frequencies is done by.........

$A$ message signal is super-imposed with a carrier signal. The resulting modulating signal $C_m(t)$ is given by $C_m(t)=A_1 \sin \left(\omega_1 t\right)+A_2 \sin \left(\omega_2 t\right)-A_2 \sin \left(\omega_3 t\right)$,where $\omega_2 < \omega_1 < \omega_3$. The modulation index and the angular frequency of the message signal respectively,are

The total maximum transmitted power in amplitude modulation if the carrier output power is $1 \ kW$ is

Television signals broadcast from the moon can be received on the earth,while the $TV$ broadcast from Delhi cannot be received at places about $100 \, km$ distant from Delhi. This is because: