What does a Sun Protection Factor (SPF) of 6 indicate?

A Sun Protection Factor (SPF) of 6 indicates that a person can theoretically be exposed to sunlight for six times longer without burning compared to not using any sunscreen. This means that if a person would typically begin to burn after 10 minutes of sun exposure, using a sunscreen with an SPF of 6 would extend that time to approximately 60 minutes, assuming proper application and adequate amounts of sunscreen were used.

This concept is crucial for understanding how SPF works in protecting the skin from harmful effects of UVB rays, which are primarily responsible for sunburn. Higher SPF numbers provide increased protection, indicating that those with fair skin or those who are particularly sensitive to sunlight should consider using products with higher SPF values for better protection.

In contrast, the other options do not accurately describe the SPF concept. An SPF measurement does not correlate to a specific number of hours of protection, nor does it refer to skin hydration. Additionally, it does not define a maximum exposure time without sunblock; rather, it illustrates how long one can endure sun exposure before risking a burn. Thus, the correct answer is the one that appropriately describes the meaning of SPF in relation to sun exposure duration.