The foam in its entirety looks white because when light enters the soap solution, it must pass through a number of tiny soap bubbles, i.e., a number of surfaces. These countless surfaces scatter the light in different directions, which makes the foam/lather look white.

Why are soap bubbles so colorful? The colors of a soap bubble come from white light, which contains all the colors of the rainbow. When white light reflects from a soap film, some of the colors get brighter, and others disappear. You can think of light as being made up of waves—like the waves in the ocean.

When an incoming ray of light strikes the outer surface of a bubble, part of the light ray is reflected immediately, while the other part is transmitted into the soap film. After reaching the inner surface of the film, this transmitted light ray is reflected back toward the outer surface.

Answer. Explanation: When a beam of sunlight falls on the soap bubble it get dispersed in to its constituent colours and this phenomenon is known as Dispersion of light. Here , the soap bubbles acts as small prism from which sunlight gets dispersed in to its seven constituents colours known as VIBGYOR.

The wave reflected from the bottom surface has traveled further (an extra distance equal to twice the thickness of the film) so emerges out of step with the top wave. When the two waves meet, they add together, and some colors are removed by destructive interference.

Thin-film interference is a natural phenomenon in which light waves reflected by the upper and lower boundaries of a thin film interfere with one another, either enhancing or reducing the reflected light. The true thickness of the film depends on both its refractive index and on the angle of incidence of the light.

For an ultrathin film, the thickness of the film is negligible compared to the wave length of light. So as ‘t’ → 0, the path difference ∆x = 2µtCosθ can practically taken to be zero as compared to wave length for all values of θ. So ∆x = 0 corresponds to a zero order minima for reflected fringes for all ‘θ.

Which of the following does not show any interference pattern? Explanation: An excessively thin film shows no interference pattern because in that case, as the thickness of the film is negligible, the path difference, Δ, between the two reflected rays turns out to be λ/2 which is the condition of minima.

Coherent Source Example Laser light is an example of coherent source of light. The light emitted by the laser light has the same frequency and phase. Sound waves are another example of coherent sources.