When waves pass through a gap that is equal to their wavelength, a phenomenon known as diffraction occurs. Diffraction is the bending or spreading of waves as they encounter an obstacle or pass through an opening. The specific behavior of diffraction depends on the size of the gap relative to the wavelength of the waves.
When a wave passes through a gap that is equal to its wavelength, several things can happen:
Wavefront spreading: The wavefront of the wave spreads out in all directions as it passes through the gap. This spreading occurs because each point on the wavefront acts as a source of secondary spherical waves, and these secondary waves interfere with each other, resulting in a spreading effect.
Huygens-Fresnel principle: The Huygens-Fresnel principle states that every point on a wavefront can be treated as a source of secondary waves. When a wave passes through a gap equal to its wavelength, each point on the wavefront acts as a new source of spherical waves. These secondary waves interfere with each other, resulting in a diffraction pattern.
Diffraction pattern: The diffraction pattern consists of alternating bright and dark regions, known as interference fringes. The bright regions correspond to constructive interference, where the waves reinforce each other, while the dark regions correspond to destructive interference, where the waves cancel each other out. The exact pattern depends on the specific geometry of the gap and the wave's characteristics.
Overall, when waves pass through a gap equal to their wavelength, they exhibit significant diffraction effects, resulting in the spreading of the wavefront and the formation of a distinct interference pattern. This phenomenon is observed in various wave systems, including light, sound, and water waves.