Historia

Waves

Properties of waves are common to all type of waves. It doesn’t matter if they are mechanical or electromagnetic. Waves can:

← Be reflected
← Be reflected in atransparent object
← Diffracted
← Produce interference

[pic]

It is important to realize that a wave is quite a different object than a particle. A baseball thrown though a windowtransfers energy from one point to another, but this involves the movement of a material object between two points. A common example of a wave is a wave on the ocean - we know they carry energy, as theycause erosion on the shore, but material (i. e. , water) is not continuously being transferred onto the shore. Another example of a wave is a sound wave, which is vibrations of air molecules whichpropagate from one place to another. These also carry energy, but do not involve the mass movement of air from one place to another.
A simple type of wave is illustrated below. 
[pic] 

bove is adisplacement / distance graph showing a wave. It is labeled with some key terms

Amplitude is the height of the wave from 0 displacement (normal) to the peak, where the peak is the highest point.The Wavelength is the distance from the start to the second point the wave passes 0. i.e. a complete wave.

Period: if it was a displacement/time graph, the period would be equivalent to wavelength, soperiod is the time for the wavelength. The frequency is 1 / period and measured in Hz (1Hz = 1wave per second).

The main properties of waves are defined below.        
• Amplitude: the height ofthe wave, measured in meters.
• Wavelength: the distance between adjacent crests, measured in meters.
• Period: the time it takes for one complete wave to pass a given point, measured inseconds.
• Frequency: the number of complete waves that pass a point in one second, measured in inverse seconds, or Hertz (Hz).
• Speed: the horizontal speed of a point on a wave as it...