Radio Waves & Electromagnetic Fields SIM Homework Answer Key
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 Physics 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. Electromagnetic 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 electron 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 change 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 electrons. This force propagates out as a wave as the signal travels at the speed of light. b) How does your antenna work to detect this electromagnetic signal produced when radio stations broadcast? Include the physics principles that support your description of how this signal is detected. Electromagnetic radiation is a form of energy that exerts a steadily oscillating force on charges (electrons)... first the force will be exerted strongly in one direction then this will reverse and the electron will feel a strong force in the opposite direction, and the cycle will continue. In the radio antenna,