For transmitting a signal of frequency $1 \text{ kHz}$,the wavelength of the wave should be:

The $T.V.$ transmission tower in Delhi has a height of $245 \ m$. The distance up to which the broadcast can be received (taking the radius of the earth to be $6.4 \times 10^6 \ m$) is .......... $km$.

The layer of the atmosphere which efficiently reflects high frequency waves particularly at night is

The maximum distance up to which $TV$ transmission from a $TV$ tower of height $h$ can be received is proportional to

We do not transmit low frequency signals to long distances because:
$(a)$ The size of the antenna should be comparable to signal wavelength,which is impractical for a signal of longer wavelength.
$(b)$ Effective power radiated by a long wavelength baseband signal would be high.
$(c)$ We want to avoid mixing up signals transmitted by different transmitters simultaneously.
$(d)$ Low frequency signals can be sent to long distances by superimposing them with a high frequency wave.
Therefore,the most suitable options are:

An $AM$ wave has $1800 \,W$ of total power content. For $100 \%$ modulation, the carrier should have power content equal to: (in $\,W$)