interference: Quick Facts

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Figure 12: A simple beat wave of amplitude ξ moving with velocity U (see text).

Figure 2: Interference of two plane waves AB and CD with directions inclined at an angle α. The crests of CD are represented as C1D1, C2D2, etc., and the troughs are shown as broken lines (see text).

Three graphs illustrate types of light wave interference. The top shows constructive interference with two waves combining to form a larger wave. The middle shows partial destructive interference, where the waves partially cancel, resulting in a smaller combined wave. The bottom shows complete destructive interference, where two waves of equal amplitude and opposite phase cancel each other out, resulting in a flat line.

Figure 9: The Michelson interferometer.

Figure 11: Multiple-beam interference. Lens L concentrates all beams at focus Q with the same phase differences they had prior to entering the lens.

$Diagram of a single-slit diffraction experiment showing light waves spreading through a narrow opening, creating alternating bright and dark bands on a screen. Insets show constructive and destructive interference, and a curve plots the brightest central band with weaker side peaks.$

Diagram of Young's double-slit experiment: light from one source passes through two slits, producing overlapping waves that create alternating bright constructive-interference and dark destructive-interference bands on a screen, matched by an intensity curve.

Understanding wave interference through sound experiments

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Topics

traveling wave cross talk destructive interference constructive interference wave train oscillating wave modulation of waves beat interference fringe Young’s experiment absorption radiation wave motion vibration phase frequency scattering wavenumber period Doppler effect

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Key People

Fresnel, detail of an engraving by Ambroise Tardieu after a contemporary portrait, 1825

Augustin-Jean Fresnel

French physicist

Thomas Young, engraving

Thomas Young

British physician and physicist

Italian-born physicist Dr. Enrico Fermi draws a diagram at a blackboard with mathematical equations. circa 1950.

Physics and Natural Law