Communications: Ground wave Propagation (I wasn't having any tag for this question(Example: Communication-Systems, Modern-physics.))
I was studying ground wave propagation, my book writes the lines about it without explaining it. I really do not know any explanation for these queries coming in my mind. I've Googled it, and you will get nothing so good for these queries on Ground wave propagation.

(1) When the radio signal travels along the earth's surface, how it induces current in it? (I read somewhere that the electric field part of the wave will make electrons go out of association with the nucleus, all this happening in earth, hence currents, Umm... Yeah! OK!, that's good.)
(2)Then, about it i know nothing, how the wave will tilt towards the earth after the induction of current in the earth?
(3) The attenuation of the surface increases very rapidly with increase in frequency of the signal. How?

Note: Answer only for the level of Class $12$ students required.
I seriously do not know anything about the last two questions. Any help would be praised for the one who will solve all these three questions.
 A: 1) Radio-wave do not make electrons dissociate from their nucleus--that would be ionizing, and RF is not ionizing radiation. Rather, the Earth is conductive, so their are free electrons present, and they can produce currents in response to an electric field. Note that the link you provided explains that ground wave propagation is more effective in regions of higher conductivity: sea water, wet/moist agriculture land and marshes, while dry desert is not as effective. The dielectric properties of the ground matter too. (note: the dielectric constant pertains to bound electron in the material--where they become polarized in response to an external electric field).
2) Looking just at the dielectric part: that is an index of refraction, hence, the waves propagate more slowly in/near the ground--this is how a lens works. Note that ground-wave propagation is relevant for LF-MF signals, or wavelengths from 10 km down to 100m--so that is the size-scale for diffraction.
3) Losses due to the so-called dissipation factor are proportional to frequency, that's just from putting a plane wave into Maxwell's equations. The dielectric, conductive, and dissipative (i.e. resistance) of materials are also frequency dependent--but I don't have a grade-12 explanation of that.
A: The waves you call "ground waves" are electromagnetic waves that only propagate along an interface between two dielectrics, where one has a negative permittivity. They are called Zenneck waves. Such waves occur at the surface of the earth because the earth is conductive and displays a negative permittivity due to its conductance in the low frequency (below MHz) range. These waves follow the curvature of the earth which enables long wave radio tranmission around the globe.
