Why does red light pass through easily in red cellophane? What happens to the green light as it passes through the red cellophane?
The correct answer and explanation is:
Correct Answer:
Red light passes through red cellophane easily because the material transmits red wavelengths while absorbing other colors. Green light is absorbed by the red cellophane and does not pass through effectively.
300-Word Explanation:
Cellophane is a type of transparent or semi-transparent material that can be dyed with pigments to allow certain wavelengths of light to pass through while blocking others. When light hits a colored material like red cellophane, its behavior depends on the wavelength (or color) of the light and the pigment properties of the material.
Visible light is made up of different colors, each with a different wavelength. Red light has a long wavelength (~620–750 nm), while green light has a shorter wavelength (~495–570 nm). Red cellophane appears red because it transmits red wavelengths and absorbs most of the others.
When white light—which contains all the colors of the spectrum—shines on red cellophane, the red wavelengths pass through, while the green, blue, and other non-red wavelengths are absorbed by the dye molecules in the cellophane. This selective transmission is due to the material’s filtering properties. The dye in red cellophane contains pigments that resonate with the energy of non-red wavelengths, converting that light energy into heat or reflecting it away. As a result, green light does not pass through and instead is filtered out.
So, if you shine green light on red cellophane, very little or no light will come through because the green light is mostly absorbed. That’s why red cellophane can make everything seen through it appear tinted red—it is only allowing red light to reach your eyes.
In practical terms, this principle is used in stage lighting, photography, and experiments involving light filters to isolate specific wavelengths of light. Understanding how light interacts with colored materials helps us manipulate and use light more effectively in technology and science.