Question

When exposed to sunlight, thin films of oil on water often exhibit brilliant colors due to the phenomenon of:
A) The dispersion
B) The interference
C) The diffraction
D) The angular acceleration

Answer 1

Hint: Recall definitions of dispersion, interference and diffraction. Speed of light has nothing to do with angular acceleration. Dispersion and interference are related terms.

Complete step by step solution:
The phenomenon of splitting of visible light into its component colors is known as dispersion. Dispersion of light is caused when there is a change of speed of light ray of each wavelength by a different amount. White light comprises seven different wavelengths with colors whereas black (or dark) signifies the absence of light rays. This phenomenon is observed when white light is made to pass through a prism.

In this case no prism is involved hence Option (A) is incorrect.

Diffraction of light is defined as the bending of light around corners of objects such that it spreads out and illuminates an area where a shadow is expected. Diffraction and interference both occur simultaneously. An example of diffraction of light is the silver lining which we witness in the sky. This is not responsible for the brilliant colors we see as mentioned in the question.

Hence Option (C) is also incorrect.

Interference of light is a phenomenon that happens at every place and at every moment. Although we don’t see interference patterns easily. Interference is the phenomenon in which two different light waves superimpose to form the resultant wave. The most common example of interference of light is the soap bubble which reflects wide colors when illuminated by a light source.

Hence Option (B) is the correct option.

Note: Don’t confuse between dispersion and interference. This phenomenon occurs when light coming out of the bubble interferes with the light coming inside the bubble.