Which of the following frequencies does not belong to the $FM$ broadcast band (in $,MHz$)?

What are the primary causes of signal attenuation in an optical fiber?

The maximum amplitude of an $AM$ wave is $90 V$ and the minimum amplitude is $10 V$. What is the original amplitude of the carrier wave in the given $AM$ wave in $V$?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. $AM$ Broadcast	$I$. $88-108\,MHz$
$B$. $FM$ Broadcast	$II$. $540-1600\,kHz$
$C$. Television	$III$. $3.7-4.2\,GHz$
$D$. Satellite Communication	$IV$. $54-890\,MHz$

Choose the correct answer from the options given below:

If $f_m$ is the modulation frequency for $FM$,then the modulation index is proportional to.....

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	$IV$. $65-75 \ km$