Spring 2006UCSD: Physics 8; Examples of Electromagnetic Waves/Radiation Radio Waves (AM and FM radio waves andTV signals) Cell phone communication links Microwaves Infrared radiation Light X-rays Gamma rays What distinguishes these from one another?

That this set of waves passed by a point in one second. There are 5 waves in this picture. The frequency of this wave is therefore 5 cycles per second (Hz). This set of waves passed by the same point in one second. There are 13 waves in this picture. The frequency of this wave is therefore 13 cycles per second (Hz). Low Frequency High Frequency

A. Radar  Radar (radio detection and ranging) devices send out short pulses of microwaves, count the time until they return, and then calculate the distance to an object.  Radar is used to monitor airplanes, ships, and to track weather systems. Police use radar guns to calculate the speed of drivers.

Infrared Lie-detection Before the lie After the lie

The military uses IR to see objects it considers relevant IR light penetrates fog and smoke better than visible light.