If a single slit is placed between the double slit and the receiving screen in the double-slit light experiment, the resulting interference pattern will be modified. This setup is commonly known as the "Young's double-slit experiment with a single slit."
The single slit acts as an additional source of diffraction, creating its own diffraction pattern. When light passes through the double slit, it produces an interference pattern characterized by bright and dark fringes on the receiving screen. However, when the light from the double slit passes through the single slit, it undergoes diffraction, resulting in a broader central peak and multiple smaller peaks on either side.
The overall pattern observed on the receiving screen will be a combination of the interference pattern from the double slit and the diffraction pattern from the single slit. The interference fringes from the double slit will still be present but modified by the presence of the single slit's diffraction pattern. This combination leads to a more complex pattern with additional interference fringes and broader central maximum.
The exact pattern depends on the dimensions and characteristics of the slits used, such as their widths, separation, and the wavelength of light being used. The resulting pattern is a superposition of the interference and diffraction effects, creating a fascinating and intricate distribution of light intensities on the screen.