How does the size of the slit affect the diffraction pattern?

The size of the slit has a significant impact on the diffraction pattern produced when light passes through it. Here’s how:

1. Slit Width vs. Wavelength: Diffraction effects become noticeable when the slit width is comparable to the wavelength of the light passing through.
2. Narrower Slit → Wider Central Maximum:
   • When the slit becomes narrower, the central bright fringe (central maximum) in the diffraction pattern becomes wider.
   • This is because the light spreads out more as it passes through a smaller opening.
3. Wider Slit → Narrower Diffraction Pattern:
   • Increasing the slit width causes the central maximum to become narrower and the diffraction fringes to be closer together.
   • This means less spreading of light after the slit.
4. Intensity Changes:
   • A narrower slit also reduces the overall light intensity because less light passes through.
   • The fringes are more spread out but dimmer.
5. Mathematically (without equations):
   • The angular width of the central maximum is inversely proportional to the slit width.

Summary:

• Smaller slit → More pronounced diffraction → Wider and more spread out pattern.
• Larger slit → Less diffraction → Narrower, more concentrated pattern.