The advantages of optical fiber communication over a two-wire transmission line or coaxial cable are . . . . . . .

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

$A$ bandwidth of $6 \, \text{MHz}$ is available for $A.M.$ transmission. If the maximum audio signal frequency used for modulating the carrier wave is not to exceed $6 \, \text{kHz}$,the number of stations that can be broadcasted within this band simultaneously without interfering with each other will be ..... .

If the maximum and minimum amplitudes of a modulated wave are $25 \ V$ and $5 \ V$ respectively,then the modulation index is

The radius of the Earth is $6400 \text{ km}$. If the height of the antenna is $500 \text{ m}$, then its range is: (in $\text{ km}$)

For a coaxial cable,the typical repeater spacing is approximately............$km$.