An isotherm is best described as what?

An isotherm is best described as what?

• A. A tool to colorize an area of the same radiation intensity
• B. A device measuring distance
• C. A measure of energy absorbed
• D. A color legend with different temperatures

Answer: (A)

An isotherm is a line that marks all points on the thermogram with the same temperature, creating boundaries that separate areas of equal radiation intensity. This helps colorize or shade regions by temperature, so you can quickly see where temperatures are uniform and where they change. The other descriptions don’t fit: it isn’t a distance-measuring device, it isn’t a direct measure of energy absorbed, and it isn’t just a color legend—it's the boundary that defines equal-temperature areas, used to map the temperature distribution on the image.

An isotherm is a line that marks all points on the thermogram with the same temperature, creating boundaries that separate areas of equal radiation intensity. This helps colorize or shade regions by temperature, so you can quickly see where temperatures are uniform and where they change. The other descriptions don’t fit: it isn’t a distance-measuring device, it isn’t a direct measure of energy absorbed, and it isn’t just a color legend—it's the boundary that defines equal-temperature areas, used to map the temperature distribution on the image.