$A$ transmitting antenna covers a range of $12.8 \ km$. Find the height of the antenna in $m$. (Radius of the Earth $= 6400 \ km$)

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	$IV$. $65-75 \ km$

In $AM$ transmission,the bandwidth of transmission is $10 \, kHz$ and the carrier frequency is $100 \, kHz$. Then,the sideband frequencies are given by:

The maximum amplitude of an amplitude modulated wave is $16 \,V$, while the minimum amplitude is $4 \,V$. The modulation index is

An audio signal $v_{m} = 20 \sin(2 \pi \times 1500 t)$ amplitude modulates a carrier $v_{c} = 80 \sin(2 \pi \times 100,000 t)$. The value of percent modulation is..........

$A$ transmitter transmits a power of $10\, kW$ when modulation is $50\%$. The power of the carrier wave is.......$kW$.