BRAINCAKETwo Slit Interference
In Young's double slit experiment, light passes through two narrow slits close together. Each slit diffracts the light, so the two beams overlap and interfere, producing a pattern of equally spaced bright and dark fringes on a screen. This was historic evidence that light is a wave.
The two slits must act as coherent sources. A laser gives coherent light directly. With an ordinary lamp, light first passes through a single slit so that both double slits are lit from the same wavefront.
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Key terms in this lesson
- coherent
- Describes sources or waves that have the same frequency and a constant phase difference between them.
More in Waves
- Speed and Frequency of Waves on a Stretched String
- Investigating the Factors Affecting Fundamental Frequency
- Fundamental Frequency
- Diffraction
- Factors Affecting Diffraction
- Single Slit Diffraction
- The Diffraction Grating
- Investigating Diffraction with a Laser
All 22 lessons in Waves · All Edexcel AS-level Physics topics