A sun-screen suntan lotion that has an SPF rating of 16. What does this mean in terms of sun exposure?

Question

Quizplus · Accepted Answer

An SPF rating of 16 increases the skin's natural sunburn protection by a multiple of 16. This means that it would take 16 times longer for someone using this sunscreen to get sunburned compared to someone not using any sunscreen. However, it does not mean that a person can have 16 hours of sun exposure without burning, as the length of time one can spend in the sun without burning depends on multiple factors such as skin type, time of day, and geographic location. It also does not increase the skin's natural sunburn protection by a multiple of 2 or 4, as the SPF rating is not a linear scale.

A Sun-Screen Suntan Lotion That Has an SPF Rating of 16