UV-Vis Spectrophotometry

Which of the following best describes electromagnetic radiation?

• A stream of charged particles moving through a magnetic field

• The flow of electric current through a conductive medium

• Oscillating electric and magnetic fields traveling through space at the speed of light

• A form of energy stored in atomic nuclei and released during radioactive decay

Why is electromagnetic radiation commonly used to identify, assay, and perform impurity tests on organic compounds?

• Organic compounds easily ionize when exposed to electromagnetic radiation.

• Organic compounds contain functional groups, double bonds, and triple bonds that interact uniquely with different wavelengths of electromagnetic radiation.

• Electromagnetic radiation causes organic compounds to form stable precipitates, making them easier to analyze.

• Organic compounds are transparent to most forms of electromagnetic radiation, simplifying detection.

Which of the following correctly matches the wavelength ranges of different regions of electromagnetic radiation used in organic compound analysis?

• UV region: 200–400 nm, VIS region: 400–760 nm, IR region: 2.5–15 µm

• UV region: 220–300 nm, VIS region: 300–750 nm, IR region: 1–10 µm

• UV region: 200–600 nm, VIS region: 600–900 nm, IR region: 0.5–5 µm

• UV region: 150–350 nm, VIS region: 350–800 nm, IR region: 5–20 µm

Which of the following best describes Lambert-Beer’s Law in spectrophotometry?

• The absorbance of a solution is directly proportional to the concentration of the absorbing species and the path length of the sample.

• The transmittance of a solution increases as the concentration of the absorbing species increases.

• The intensity of transmitted light is independent of the sample concentration and path length.

• The absorbance of a solution remains constant regardless of changes in concentration or path length.

Which type of cuvette is most suitable for measurements in the UV and visible (VIS) regions of the electromagnetic spectrum?

• Quartz for both UV and VIS, while glass and plastic are only for UV

• Plastic for UV, quartz for VIS, and glass is not suitable for either

• Glass for UV, plastic for VIS, and quartz for both

• Quartz for UV, glass and plastic for VIS, but quartz can also be used for VIS