The perception of color is influenced by the interaction between light and objects. When we see an object as a particular color, it means that the object is reflecting or transmitting light of that specific wavelength.
In the case of red objects, they appear red because they selectively reflect or transmit light in the red wavelength range. Although red light has a longer wavelength compared to other visible colors (such as blue or violet), it doesn't mean that only light with long wavelengths can reach the object.
When you see a red object that is as close as 3 feet away, it means that light from various sources is reaching the object and interacting with it. These light sources can include natural or artificial light, which emit a broad spectrum of wavelengths. Even though there might be light of shorter wavelengths (such as blue or green) present in the vicinity of the object, the object's surface selectively reflects or transmits light in the red wavelength range.
The perception of color is a complex process that involves the interaction between light, objects, and our visual system. Our eyes have receptors called cones that are sensitive to different wavelengths of light. When light of a specific wavelength, such as red, stimulates the corresponding cone cells in our eyes, we perceive the object as red.
Therefore, even though red light has a longer wavelength, objects can appear red even when they are as close as 3 feet away due to the selective reflection or transmission of light in the red wavelength range by those objects.