Radio waves of constant amplitude are produced by a/an . . . . . . .

Which characteristic of a carrier light wave is modulated for the modulation of a light wave?

The process of superimposing low-frequency signals onto high-frequency carrier waves is called ..........

For amplitude modulated wave broadcast, which of the following conditions is suitable?

$A$ square wave of the modulating signal is shown in the figure. The carrier wave is given by $C(t) = 5 \sin(8\pi t) \text{ V}$. The modulation index is:

Define the following terms:
$(a)$ Ground waves
$(b)$ Trade winds