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Wavelength is the length of a single cycle of a wave, as measured by the distance between one peak of a wave and the next. It is often designated as λ.

Wavelength is designated as λ here.

In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.[1]

The concept can also be applied to periodic waves of non-sinusoidal shape.[1][2] The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.[3]

Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.[4]

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  1. 1.0 1.1 Hecht, Eugene (1987). Optics (2nd ed.). Addison Wesley. pp. 15–16. ISBN 0-201-11609-X. 
  2. Brian Hilton Flowers (2000). "§21.2 Periodic functions". An introduction to numerical methods in C++ (2nd ed.). Cambridge University Press. p. 473. ISBN 0198506937. http://books.google.com/books?id=weYj75E_t6MC&pg=RA1-PA473. 
  3. Keqian Zhang and Dejie Li (2007). Electromagnetic Theory for Microwaves and Optoelectronics. Springer,. p. 533. ISBN 9783540742951. http://books.google.com/books?id=3Da7MvRZTlAC&pg=PA533&dq=wavelength+modulated-wave+envelope. 
  4. Theo Koupelis and Karl F. Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. ISBN 0763743879. http://books.google.com/books?id=WwKjznJ9Kq0C&pg=PA102&dq=wavelength+lambda+light+sound+frequency+wave+speed.