radio waves, cell phone signals and WiFi
Don't need to refer to photons. Just coupled electrical and magnetical fields as described in the Maxwell equations. Air and vacuum has relative permittivity around 1, sufficient to carry AC currents.
Presumably you think satellite communications cannot work and Sunlight only exists in everyone's imagination, they all pass radiation through vacuum too.
Brian.
air is an insulator - but not a very good insulator
this shows up, in part, via snell's law
the index of refraction is n = c/v(medium)
which in vacuum is c/c, or 1 (exactly)
the index of refraction of air is (about) 1.0004, hence, for most purposes
we can treat air as the same as vacuum
electromagnetic waves do not consist of electrons
EM waves are waves of time varying and space varying electric and magnetic fields
per Faraday and Maxwell, changing electric fields induce magnetic fields,
and changing magnetic fields induce electric fields, hence EM waves are self propagating
(that is, they re-induce themselves continuously)
EM waves include, but are not limited to, gamma through radio, as in the chart.
visible light is that short portion that we see as colors.
there is no reason to believe the chart stops at either end.
the chart shows the limit of our ability to observe and produce EM waves.
also, electrons (and hence current) do not need a medium to travel through
there are a variety of particle accelerators (cyclotrons, synchronous, etc) that
accelerate all manner of particles in a vacuum.
these also occur naturally, such as the solar wind and cosmic rays (muons, etc)
I thought photons referred to only light particles/waves.
Shouldn't electromagnetic waves be stopped in an insulator? Because they don't have any conductivity to move.
Aren't electromagnetic waves made up of electrons? Electrons need conductive material to move, air is mentioned in textbooks as an insulator, so I'm confused how they can move in air.
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