Radio Waves & Electromagnetic Fields SIM Homework
1) For this question, use the Radio Waves & Electromagnetic Fields
simulation to guide your understanding of how Radio broadcasting and Radio
receivers work.
This simulation is available at the P hysics 1010 Homepage.
a)
How is the radiating electric field (or electromagnetic signal) produced when
radio
stations broadcast? Include a description of what is producing the signal as
well as the
reasoning behind how this could produce a signal.
Electro
magnetic radiation is produced by accelerating charges. In the
radio transmitter, electrons oscillate up and down and are thus
accelerating. An electron will exert a force on another electron when
they are some distance away, like charges repel. When the e
lectron in
the transmitter oscillates up and down, the direction of the force it
exerts changes since the source of the force (the oscillating electron) is
moving. It takes some time for the change in this direction of the force
to be felt since this chang
e is communicated or propagated out at the
speed of light. In addition, the horizontal component of this force is
canceled by the positive charges in the transmitting antenna. So, the
resulting force is an oscillating force that pushes vertically on electr
ons.
This force propagates out as a wave as the signal travels at the speed of
light.