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Destructive Interference

Reference from the original Physics I textbook.

Destructive Interference

Destructive interference occurs when overlapping disturbances oppose one another. Two otherwise identical sinusoidal waves with phase difference π have resultant amplitude |A₁ − A₂|, which is zero for equal amplitudes.

Gallery9.1.2.2 — details in the accompanying text.

Related Glossary Terms

Constructive Interferenceⓘ, Two Wave Interference Equation, Wave Interference Equation, Waves with Equal Amplitude and Angular Frequency

Index

Chapter 9 - Mechanical Waves

Reviewed physics notes (1)

These corrections keep the original lesson’s purpose while fixing errors in the source edition.

  • The result is reduced amplitude, not a shorter wavelength. — Reference 1

About this edition and its source ↗

Glossary and deeper reading · 2 refreshers

These editorial refreshers supplement the reading. Definitions and examples are added guidance; original source wording and recorded answers remain in their original context.

  • Destructive interference

    Destructive interference occurs when overlapping wave contributions oppose one another. Complete cancellation requires equal-magnitude opposite disturbances at the relevant place and time. For example, equal sinusoidal waves half a cycle out of phase can produce zero net displacement during their overlap.

    Read more: Destructive interference in detail →

  • Constructive interference

    Constructive interference occurs when overlapping wave contributions reinforce one another. For equal-frequency sinusoidal waves, in-phase contributions produce increased amplitude at the location considered. For example, coherent light arriving with an integer-wavelength path difference can form a bright interference fringe.

    Read more: Constructive interference in detail →

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