Diffraction and interference are closely related phenomena that occur together. Diffraction is the phenomenon of bending of light around the edges of the obstacle, while interference is the combination of waves that results in a new wave pattern. In order to get interference, there must be at least two waves that are diffracting. So while diffraction can occur without interference, interference cannot occur without diffraction. Two slits of width $2 \text{ }\mu\text{m}$ each in an opaque material are separated by a distance of $6 \text{ }\mu\text{m}$. Monochromatic light of wavelength $450 \text{ nm}$ is incident normally on the slits. One finds a combined interference and diffraction pattern on the screen.