Final answer:
A person should wait 20 minutes after applying sunscreen before going into the sun to allow it to bond with the skin, providing protection against UVA and UVB rays with a recommended minimum SPF of 30.
Step-by-step explanation:
The correct option : c
After applying sunscreen, it is recommended to wait about 20 minutes before going out into the sun. This waiting period allows the sunscreen to properly bond with the skin, providing the intended level of protection against harmful ultraviolet (UV) radiation. When selecting a sunscreen, it's important to choose a product with a sun protection factor (SPF) of at least 30 to ensure broad spectrum coverage against both UVA and UVB rays.
The SPF indicates the level of protection from UVB radiation specifically, and while a higher SPF may offer marginally more protection, an SPF of 30 filters out 97% of UVB rays, which is generally considered sufficient for most people. Moreover, sunscreens and sunblocks are not waterproof but can be water-resistant, and they should be reapplied every two hours, especially after sweating or swimming, to maintain effectiveness.