In an amplitude modulation with modulation index $0.5$, the ratio of the amplitude of the carrier wave to that of the sideband in the modulated wave is

$1000\, \mathrm{kHz}$ carrier wave is amplitude modulated by the signal frequency $200$–$4000 \,\mathrm{Hz}$. The channel width of this case is,

A carrier frequency of $1 \mathrm{MHz}$ and peak value of $10 \mathrm{V}$ is amplitude modulated with a signal frequency of $10 \mathrm{kHz}$ with peak value of $0. 5 \mathrm{V}$. Then the modulation index and the side-band frequencies respectively are

This question has Statement$-1$ and statement$-2$. Of the four choices given after the statements, choose the one that best describes the two statements.

Statement$-1$: Skywave signals are used for long-distance radio communication. These signals are in general, less stable than ground wave signals.

Statement$-2$: The state of the ionosphere varies from hour to hour, day to day and season to season.