Physics Help??

1. For a single slit, how must the size d of the slit compare to the wavelength of light for a diffraction pattern to occur?

2. If the slit spacing d decreases does the angular spread of the diffraction pattern on the screen increase or decrease? e.g., in Figure 2 does theta2 increase or decrease as d decreases? Explain

3. If the single slit width a decreases does the angular spread of the diffraction pattern on the screen increase or decrease? If the slit width a decreases does theta2 increase or decrease? Explain.