Therapeutics: sunscreens: practice question

A Dermatology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dermatology · Therapeutics: sunscreens

Sample item

The sun protection factor (SPF) printed on a sunscreen primarily indicates protection against which radiation?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. UVB, as the ratio of minimal erythema dose with and without sunscreen

SPF is the ratio of the UV dose that causes minimal erythema on protected skin to that on unprotected skin, so it reflects mainly UVB protection. Broad-spectrum labelling and UVA ratings indicate UVA cover.

Option by option

  • A. UVA only

    UVA protection is rated separately, for example by PA grading.

  • B. UVB, as the ratio of minimal erythema dose with and without sunscreen (correct)

    Correct. SPF reflects sunburn (UVB) protection.

  • C. Visible light

    SPF does not measure visible light protection.

  • D. Infrared

    SPF does not measure infrared protection.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Dermatology questions

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is B, UVB, as the ratio of minimal erythema dose with and without sunscreen. SPF is the ratio of the UV dose that causes minimal erythema on protected skin to that on unprotected skin, so it reflects mainly UVB protection.

Why is "UVA only" not the answer?

UVA protection is rated separately, for example by PA grading.

Why is "Visible light" not the answer?

SPF does not measure visible light protection.

Why is "Infrared" not the answer?

SPF does not measure infrared protection.

What concept does this question test?

It tests Therapeutics: sunscreens in Dermatology. Broad-spectrum labelling and UVA ratings indicate UVA cover.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Therapeutics: sunscreens?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.