The angular width of the central maximum in single-slit diffraction refers to the angle over which the central bright fringe extends on either side of the central axis.
In simple terms, when light passes through a narrow slit and forms a diffraction pattern on a screen, the central maximum is the brightest and widest part. This central bright fringe is bordered by the first dark fringes (minima) on either side.
Key Concepts:
- The angular width is defined as the angle between the first minima on either side of the central maximum.
- It depends on the wavelength of light and the width of the slit.
- If the slit is narrower, the angular width is broader.
- If the slit is wider, the angular width is narrower.
- A larger wavelength (like red light) results in a wider central maximum compared to a smaller wavelength (like blue light).
So, the angular width shows how “spread out” the central maximum appears due to diffraction and is a crucial factor in the resolution and performance of optical instruments like microscopes and telescopes.