In Young's double-slit experiment, the central point or the central bright band is brighter than the other fringes in the interference pattern. This central bright band is often referred to as the central maximum or central peak.
The reason for the central bright band is due to the constructive interference of light waves from the two slits. When coherent light, such as light from a laser, passes through the double slits, it splits into two coherent wavefronts, each passing through one of the slits. These wavefronts then propagate outward and overlap with each other.
At the center of the screen where the interference pattern is formed, the two wavefronts arrive in phase with each other. This means that the peaks and troughs of the waves align, resulting in constructive interference. As a result, the amplitudes of the waves add up, leading to an increased intensity of light in the central region.
In contrast, the regions away from the center experience varying degrees of destructive interference. This occurs because the path lengths from the two slits to different points on the screen differ, causing phase differences between the waves. This phase difference results in partial or complete cancellation of the waves, leading to dark fringes or minima in the interference pattern.
It's important to note that the central bright band in the double-slit experiment is not due to a single slit or a single beam of light. Instead, it arises from the interference of two coherent wavefronts that pass through the double slits.