Question

After a minor oil spill, a thin film of oil (n=1.40) of thickness 450 nm floats on the water surface in a bay.

(a) What predominant color is seen by a bird flying overhead?
(b) What predominant color is seen by a seal swimming underwater?

Answer 1

To determine the predominant color seen by a bird flying overhead and a seal swimming underwater after a minor oil spill, we need to consider the concept of thin film interference. By using the formula for constructive interference and the given parameters, we can calculate the predominant colors for each scenario.

Step-by-step explanation:

In order to determine the predominant color seen by the bird flying overhead and the seal swimming underwater, we need to consider the concept of thin film interference. When light passes from one medium to another, such as from air to oil, it undergoes a change in speed and direction. This change causes the light waves to interfere with each other, resulting in constructive and destructive interference.

(a) For the bird flying overhead, we can use the formula (2 * film thickness) = m * wavelength, where 'm' is an integer representing the order of the constructive interference. The color corresponding to the wavelength of light that satisfies this condition will be seen. Since the oil film thickness is given as 450 nm and the oil has an index of refraction of 1.40, we can calculate the wavelength of the predominant color.

(b) For the seal swimming underwater, the situation is similar to (a) except that the light is passing from water to oil. We can use the same formula to determine the predominant color seen by the seal.