The maximum number of $TV$ signals that can be transmitted along a coaxial cable is

$A$ message signal of peak voltage $12 \ V$ is used to amplitude modulate a carrier signal of frequency $1.2 \ MHz$. The amplitude of the side bands is (in $V$)

If a message signal of frequency $f_{m}$ is amplitude modulated with a carrier signal of frequency $f_{c}$ and radiated through an antenna,the wavelength of the corresponding signal in air is ....... .

If modulation index $\mu = \frac{1}{2}$ and $V_{m} = 2$,then $V_{c} = \, ?$

Match Column $A$ (layers in the ionosphere for skywave propagation) with Column $B$ (their height range).

Column $A$	Column $B$
$A$. $D$-layer	$I$. $250-400 \ km$
$B$. $E$-layer	$II$. $170-190 \ km$
$C$. $F_1$-layer	$III$. $95-120 \ km$
$D$. $F_2$-layer	$IV$. $65-75 \ km$

$A$ carrier wave of peak voltage $12 \,V$ is used to transmit a signal. If the modulation index is $75 \%$, the peak voltage of the modulating signal is (in $\,V$)