Diffraction

Definition

Diffraction is the bending of waves around obstacles or the spreading of waves when they pass through small openings. It occurs with all types of waves, including light and sound.

5 Must Know Facts For Your Next Test

1. Diffraction is most noticeable when the size of the obstacle or opening is comparable to the wavelength of the wave.
2. The diffraction pattern produced by a single slit consists of a central maximum and multiple secondary maxima and minima.
3. Huygens's Principle explains diffraction by stating that every point on a wavefront acts as a source of secondary spherical wavelets.
4. The angle at which significant diffraction occurs can be calculated using $\sin(\theta) = \frac{m\lambda}{a}$, where $m$ is an integer, $\lambda$ is the wavelength, and $a$ is the width of the slit.
5. Diffraction limits the resolution in optical instruments such as microscopes and telescopes.

Review Questions

• What principle explains why diffraction occurs?
• How does the size of an obstacle relative to the wavelength affect diffraction?
• What kind of pattern does light produce when it passes through a single slit?

Related terms

Interference:

The phenomenon where two or more waves superpose to form a resultant wave with greater, lower, or same amplitude.

Wavelength:

The distance between successive crests or troughs in a wave.

Huygens's Principle:

\text{A principle stating that every point on a wavefront can be considered as a source of secondary spherical wavelets.}