Which of the following can be better understood by studying the emitted and reflected infrared radiation from an object?

• A. The object's electrical conductivity
• B. The atomic number of elements present in the object
• C. The object's visible color
• D. The temperature and molecular composition of the object

Answer: (D)

Verified step by step guidance

1. Understand that infrared (IR) radiation is primarily associated with the vibrational and rotational transitions of molecules, which are sensitive to molecular composition and temperature.
2. Recognize that studying emitted IR radiation allows us to determine the temperature of an object because objects emit IR radiation based on their thermal energy (blackbody radiation principles).
3. Know that reflected IR radiation can provide information about the molecular composition since different molecules absorb and reflect IR light at characteristic wavelengths (IR spectroscopy).
4. Note that electrical conductivity is better studied through electrical measurements, not IR radiation, and atomic number is determined by techniques like X-ray spectroscopy, not IR.
5. Understand that visible color relates to absorption and reflection in the visible spectrum, which is different from the infrared region, so IR studies do not directly reveal visible color.