Everything Science Grade 12

11.4 CHAPTER 11. 2D AND3D WAVEFRONTS

use the Huygens Principle to determine the wavefront at a later time.

SOLUTION

Step 1 : Draw circles at variouspoints along the given wavefront

Step 2 : Join the circle crests toget the wavefront at a later time

11.4 Interference

ESCFC

Interference occurs when two identical waves pass through the same region of space at

the same time resultingin a superposition of waves. There are two typesof interference

which is of interest: constructive interference and destructive interference.

Constructive interference occurs when both waves have a displacement in the same

direction, while destructive interference occurswhen one wave has a displacement in

the opposite direction tothe other, thereby resulting in a cancellation. When two waves

interfere destructively, the resultant absolute displacement of the medium is less than

in either of the individual displacements. When total destructive interferenceoccurs,

there is no displacementof the medium. For constructive interference thedisplacement