In Young's double slit experiment, if the monochromatic source is replaced by white light, the centr

Question

In Young's double slit experiment, if the monochromatic source is replaced by white light, the central fringe is observed to be white. The color of the bright fringe closest to the central white fringe on either side will be predominantly

Professor PC Thomas Classes · Answer

(b) : The position of the $n$-th bright fringe from the central maximum is given by $y = n\frac{\lambda D}{d}$. Since the distance $y$ is directly proportional to the wavelength $\lambda$, the light color with the shortest wavelength will form its first maximum closest to the central white fringe. Among the visible colors, violet/blue has the shortest wavelength, so it appears closest to the center.