Question

An oil tanker has collided with a smaller vessel, resulting in an oil spill in a large, calm-water bay of the ocean. You are investigating the environmental effects of the accident and need to know the area of the spill. The tanker captain informs you that 10000 liters of oil have escaped and that the oil has an index of refraction of n = 1.1. The index of refraction of the ocean water is 1.33. From the deck of your ship you note that in the sunlight the oil slick appears to be blue. A spectroscope confirms that the dominant wavelength from the surface of the spill is 445 nm. Assuming a uniform thickness, what is the largest total area of the oil slick?

Answer 1

Here blue is the only dominant color due to the phenomenon of thin film interference. From the formula we can write the wavelength's for maxima as,

Here we will consider m = 1, as the deteceted wavelength is a dominant one and that is the one which is the first maxima. Here n is the refractive index of oil.

Substituting values we can calculate the thickness as,

Now we know the thickness and the volume of the oil spilled. Hence we can calculate the area of spill as, (Liter is converted to cubic meter)