Diffraction causes waves to spread out and interfere, resulting in variations in amplitude across the resulting pattern.
The Effect of Diffraction on Wave Amplitude
Diffraction is the phenomenon where waves bend around obstacles or spread out through openings. After passing through an opening or around an object, these waves interfere with each other. This interference is key to understanding how diffraction affects amplitude.
When waves interfere, their amplitudes combine. There are two main types of interference:
- Constructive Interference: This occurs when the crests of one wave align with the crests of another, and troughs align with troughs. The reference states that bright fringes, also known as maxima in a diffraction pattern, are areas where waves interfere constructively. This alignment results in a higher amplitude, which corresponds to a higher intensity (brightness) of the light.
- Destructive Interference: This occurs when the crests of one wave align with the troughs of another. This results in the waves partially or completely canceling each other out, leading to a lower or even zero amplitude. In a diffraction pattern, these areas of destructive interference form the dark fringes, also known as minima, where the intensity is low or zero.
Therefore, diffraction doesn't uniformly change the amplitude of the wave; instead, it redistributes the wave's energy, creating a pattern where amplitude varies significantly from points of maximum constructive interference (high amplitude) to points of maximum destructive interference (low or zero amplitude).
Summary of Effects
| Phenomenon | Location in Pattern | Interference Type | Amplitude Effect | Intensity Effect |
|---|---|---|---|---|
| Diffraction Pattern | Bright Fringes (Maxima) | Constructive | Higher Amplitude | Higher Intensity |
| Diffraction Pattern | Dark Fringes (Minima) | Destructive | Lower/Zero Amplitude | Lower/Zero Intensity |
In essence, diffraction leads to the formation of distinct regions of varying amplitude and intensity, rather than a uniform distribution of amplitude after passing the obstacle or opening.
