The discrepancy in perceiving sound versus sight from behind an opaque barrier stems from the distinct wavelengths characterizing light and sound waves.
Light waves possess exceptionally short wavelengths, measuring in nanometers (around \(10^{-9}\) m). These minute wavelengths are incapable of circumventing substantial obstructions like walls, which vastly exceed the light's wavelength. Consequently, light waves produce distinct shadows, preventing visual contact with individuals beyond the wall.
Conversely, sound waves exhibit considerably longer wavelengths, typically ranging from centimeters to meters. These extended wavelengths are able to diffract around the perimeters of obstacles, such as walls, thereby enabling auditory detection of a person who remains visually concealed.
This principle, the bending and spreading of waves around obstructions, is known as diffraction.
Monochromatic light of green color is used in Young’s double slit experiment and an interference pattern is observed on a screen. If the green light is replaced by red monochromatic light of the same intensity, how will the fringe width of the interference pattern be affected? Justify your answer.