Final answer:
The answer requires information about the mass and density of the GaAs thin film to calculate the area it would cover. Similar physics principles are used in other applications of thin films, like optimizing coatings on lenses and calculating electric fields and charge densities.
Step-by-step explanation:
The problem provided is related to the application of thin film interference, commonly encountered in physics and engineering coursework. To find the area a 40-nm thin film of GaAs would cover given its mass from part a, we would need the mass, the density of GaAs, and the thickness of the film. Typically, thin film interference problems like these involve calculations based on the formula Area = Mass / (Density * Thickness). Unfortunately, without the density and the mass of GaAs, we cannot solve this specific problem. However, similar types of calculations are used to determine the properties of thin films in optical applications, such as anti-reflective coatings or conductive layers.
As an example of related content, calculation of minimum film thickness for minimized reflection, determining the wavelength of visible light with limited reflection on coated lenses, and finding electric field and charge densities are all problems that require an understanding of physics, specifically electromagnetism and optics.