Final answer:
The spacing between dark bands in the interference pattern of light passing through a wedge-shaped air gap between two glass slides can be calculated using the wavelength of the light and the length of the slides. The material of the glass slides does not affect the pattern as long as the light travels through the air wedge.
Step-by-step explanation:
The question involves using the concept of interference patterns in light to determine the spacing between dark bands when two glass slides are placed together to form a wedge of air. The pattern forms due to the variation in the path length of the light between the top and bottom slides, leading to constructive or destructive interference. Using the wavelength of light provided (589 nm) and the length of the slides (7.50 cm), the pattern of dark fringes can be calculated. The material of the slides, whether they are made from crown or flint glass, would potentially affect the refractive indices, but as long as the light travels through air, the interference pattern is determined by the air wedge and not the slides' material.