According to the Informational Note referencing the Stoll model, onset of a second-degree burn on unprotected skin is likely to occur at an exposure of 1.2 cal/cm2 for 1 second.

According to the Informational Note referencing the Stoll model, onset of a second-degree burn on unprotected skin is likely to occur at an exposure of 1.2 cal/cm2 for 1 second.

• A. 0.5 cal/cm2 for 0.5 second
• B. 1.2 cal/cm2 for 1 second
• C. 2.0 cal/cm2 for 2 seconds
• D. 3.0 cal/cm2 for 3 seconds

Answer: (B)

Understanding burn thresholds involves energy per area and how long that energy acts on the skin. The Stoll model translates incident heat into tissue damage risk, and the informational note for this model gives a specific onset value: a second‑degree burn on unprotected skin is likely when about 1.2 calories per square centimeter are delivered over one second. So, the exposure that matches this exact threshold is the one delivering 1.2 cal/cm2 for 1 second. Exposures with less energy are below the onset point and unlikely to cause a second‑degree burn at that duration, while those with more energy (more energy per area or longer exposure) would exceed the threshold and produce burn effects sooner or more severely. This is why that particular exposure is identified as the onset point.

Understanding burn thresholds involves energy per area and how long that energy acts on the skin. The Stoll model translates incident heat into tissue damage risk, and the informational note for this model gives a specific onset value: a second‑degree burn on unprotected skin is likely when about 1.2 calories per square centimeter are delivered over one second.

So, the exposure that matches this exact threshold is the one delivering 1.2 cal/cm2 for 1 second. Exposures with less energy are below the onset point and unlikely to cause a second‑degree burn at that duration, while those with more energy (more energy per area or longer exposure) would exceed the threshold and produce burn effects sooner or more severely. This is why that particular exposure is identified as the onset point.