**9. Monochromators**

The monochromator is used to disperse the radiation. The essential elements of a monochromator are:

• Entrance Slit (to get narrow source)

**Figure 7.** *Mercury arc.*


Monochromators are better and more efficient than filters in converting polychromatic light or heterochromatic light into monochromatic light. The structure is depicted in **Figure 8**.
