In a Young double slit experiment performed with monochromatic light, if the distance between the slits is halved and the distance between the slit plane and the observation screen is doubled, what happens to the fringe width?

💡 Solution & Explanation

The fringe width in a Young double slit experiment is directly proportional to the wavelength of light and the distance to the screen, and inversely proportional to the separation between the slits. Halving the slit separation doubles the fringe width, and doubling the screen distance doubles it again, resulting in a net quadrupling of the original fringe width. Interference is a physical phenomenon demonstrating the wave nature of light.