Imagine that you have a very thin uniform oil film on the surface of water. The thickness of oil is much smaller than the wavelength of blue light. White light is shining on the film. What color would the film be if you looked at it from above? Explain.

Green light

Explanation:

The thickness of oil is smaller than wavelength of blue light. The wavelength 450 nm to 495 nm. Let the thickness of oil is 400 nm.

By the constructive interference formula,

2nt = mλ

2 X 1.28 X 400 X 10^(-9) = 2λ

λ = 512 nm

This is the wavelength of green light.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide