Final answer:
To evaluate the absorption of infrared radiation by substances, measuring the temperature increase upon exposure to infrared radiation is the best method using the principles of calorimetry.
Step-by-step explanation:
To compare the abilities of two substances to absorb infrared radiation, the most appropriate method would be A) Measure the temperature increase caused by each substance when exposed to the same amount of infrared radiation. This method uses the principles of calorimetry, which involves measuring the amount of thermal energy transferred to or from a substance during a physical or chemical change.
By measuring the temperature increase of each substance when subjected to infrared radiation, we can ascertain how much heat is absorbed. This absorption directly correlates to the infrared radiation absorption capability of the substance. The other options mentioned, such as observing color change, assessing visible light reflection, or examining electrical conductivity are less direct and likely to be less reliable methods of measuring a substance's ability to absorb infrared radiation.