In Young's double slit experiment, when there is only one slit instead of two, the interference pattern observed in the final pattern would disappear.
In the double slit experiment, a beam of light passes through two narrow slits and forms an interference pattern on a screen located behind the slits. This pattern consists of alternating bright and dark fringes, known as interference fringes, resulting from the constructive and destructive interference of light waves.
When there is only one slit, the interference pattern cannot be formed because there is no second slit to create the necessary interference. Instead, you would observe a diffraction pattern, which is characterized by a central bright spot, known as the central maximum, surrounded by a series of alternating bright and dark regions called diffraction fringes. The diffraction pattern arises from the bending of light waves as they pass through the single slit and spread out.
So, in summary, if there was only one slit in Young's double slit experiment, you would observe a diffraction pattern rather than an interference pattern.