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Interference

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-486

2025-12-25

624

We have already seen the results of interference in sound waves. Two waves may meet in such a way as to strengthen each other or to neutralize each other. Similar phenomena occur in light.

Demonstration. - Against a piece of plate glass press the curved side of a plano-convex lens of great focal length. On looking at the upper surface of the lens at an angle, a series of concentric circles will be seen, each one of which will be made up of the colors of the spectrum. If a sheet of red glass is placed between the lens and the light, so that light of that color alone falls upon the lens, the rings will be alternate dark and red bands. Two strips of plate glass separated at one end by a sheet of paper and pinched together at the other will also show interference bands.

The rings shown by the lens are called Newton's rings. The colors seen on looking at a thin film of oil on water, a soap bubble, or a crack in a piece of ice, are other examples of interference.