Question

A sunscreen product with an of SPF of 15 indicates:

a. the number of hours of protection from sun exposure
b. sun exposure can be 15 times longer than without protection
c. the time between reapplications of sunscreen
d. the number of times sunscreen should be applied

Answer 1

A sunscreen product with an of SPF of 15 indicates sun exposure can be 15 times longer than without protection.Thus option b is the correct answer.

Step-by-step explanation:

Sun Protection Factor (SPF) in sunscreen indicates the multiplier for the time an individual can stay in the sun without getting sunburned compared to not using sunscreen. An SPF of 15 means that, theoretically, a person can stay in the sun 15 times longer than if they were not wearing any sunscreen.

To understand this, consider the following calculation:

`\[ \text{Total Protected Time} = \text{SPF} * \text{Unprotected Time} \]`

If a person would normally start to burn after 10 minutes in the sun without protection, with an SPF 15 sunscreen:

`\[ \text{Total Protected Time} = 15 * 10 \text{ minutes} = 150 \text{ minutes} \]`

So, with SPF 15, the person should be protected from sunburn for approximately 150 minutes.

It's crucial to note that this is a rough estimate, as various factors such as sweating, swimming, and activities that rub the sunscreen off the skin can affect its effectiveness. Reapplication is recommended, especially after swimming or sweating, to maintain the intended level of protection. In summary, an SPF of 15 signifies that sun exposure can be 15 times longer than without protection, emphasizing the importance of reapplication to ensure continued safeguarding against harmful UV rays.A sunscreen product with an of SPF of 15 indicates sun exposure can be 15 times longer than without protection.Thus option b is the correct answer.

Answer 2

An SPF of 15 in a sunscreen product means that sun exposure can be 15 times longer than without protection, and it measures protection from UVB rays specifically (option b). It is advisable to use a broad-spectrum sunscreen and to reapply it every two hours or after swimming or sweating.

Step-by-step explanation:

A sunscreen product with an SPF of 15 does not indicate the number of hours of protection, but rather that sun exposure can be 15 times longer than without protection. SPF, or Sun Protection Factor, is a measure of how well a sunscreen will protect skin from UVB rays, the kind of radiation that causes sunburn and contributes to skin cancer. While an SPF of 15 can filter out approximately 93% of UVB rays, higher SPF values such as 30 or 50 filter out slightly more; however, after reaching an SPF of 30, the increase in UVB protection is minimal.

It is recommended by health organizations to use a broad-spectrum sunscreen, which protects against both UVA and UVB radiation. Sunscreens should be reapplied every two hours, or more often if swimming or sweating. No sunscreen products are waterproof, but some are water-resistant, and even then, frequent reapplication is necessary for effective protection.

Hence, the answer is option b.