1. More on Waves

2. Standing Waves
A standing wave is produced by the interference of 2 periodic waves traveling in opposite directions and in the same medium
The waves must have the same frequency, wavelength and amplitude

3. Standing Waves

4. Standing Waves
Nodes – points in medium where the displacement is always zero (constant perfect destructive interference)
Distance between adjacent nodes -
Antinodes – points in medium of maximum displacement
Distance between adjacent antinodes -

5. Huygen’s Principle Christian Huygen’s
Every point on an advancing wave front can be considered as a secondary source at which circular wavelets, like those sent out from a point source, originate.
The new wave front can be found by drawing the line tangent to all of these wavelets at a slightly later instant

6. Huygen’s Priniciple

7. Huygen’s Principle
Applet showing Principle and it’s application to reflection and refraction
Huygen’s Principle
HP and diffraction: