Calculate the molar absorptivity of the complex:

The atomic weight of iron is 56, therefore the molar concentration of the solution containing 1.00 microgram of iron (II) present in 10 mL of solution will be

(1× 10^-6g/56) × (1000mL/10mL) = 1.786×10^-6 mol per dm³.

ε = A / b.c ⇒ 0.02/1.786 mol dm^-3 × 1 cm

= 1.12 × 10⁴ dm^-3   mol ^-1   cm ^-1

 A monochromator is a device which could selectively gives radiation of a desired wavelength out of the range of wavelengths emitted by the source. In grating monochromator, a fine beam of the light from the radiation source is made to fall on a concave mirror by an entrance slit. After reflection, it falls on the grating which causes it to disperse. The dispersed radiation is after that emerges out of an exit slit. The range of wavelengths isolated through the monochromator is determined through the extent of dispersion through the grating and the width of the exit slit. Rotation of the grating in a predetermined way used to acquire the desired wavelength from the exit slit.