The ozone layer blocks from the sun?

Appeared in: ESIC Nursing Officer 2016 (shift-1)

Explanation

The ozone layer is a protective shield in the Earth's stratosphere.
Its primary function is to absorb the majority of the sun's harmful ultraviolet (UV) radiation.
Specifically, it blocks all of the highly dangerous UV-C rays and most of the UV-B rays, which are known to cause skin cancer and other health issues.
It allows beneficial visible light and less harmful UV-A rays to pass through to the Earth's surface.

Option A: Sunlight is a broad spectrum of radiation, including visible light, infrared, and UV. The ozone layer does not block all sunlight, only a specific portion (UV).
Option B: Infrared radiation is primarily absorbed by greenhouse gases like carbon dioxide and water vapor, not by the ozone layer. Infrared is mainly responsible for heat.
Option C: This option is incorrect because the ozone layer does not significantly block infrared radiation. Its blocking action is specific to UV radiation.

Visual 1: Diagram: An illustration of the Earth's atmosphere showing the stratosphere and the ozone layer within it. Arrows should depict UV-C and most UV-B being blocked, while UV-A and visible light pass through.
Visual 2: Infographic: A chart comparing UV-A, UV-B, and UV-C rays, showing their wavelengths and penetration depth into the skin, linking them to health effects like sunburn, aging, and cancer.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Function of the ozone layer as background academic context rather than a clinical decision trigger.
Nurses play a key role in public health education, including advising patients on sun safety to prevent skin cancer and other UV-related damage.
Patient education should include recommending the use of broad-spectrum sunscreen (protects against UVA and UVB), wearing protective clothing, and avoiding peak sun exposure (10 AM to 4 PM).
It is important to identify patients at higher risk for sun damage, such as those with fair skin, a history of skin cancer, or those taking photosensitizing medications (e.g., tetracyclines, diuretics).

How to Approach the Question

Identify the key terms in the question: 'ozone layer' and 'blocks'.
Recall the primary function of the ozone layer from environmental science or general knowledge.
The main purpose of the ozone layer is to act as a shield against harmful solar radiation.
Evaluate the options. 'Sunlight' is too broad. 'Infrared' is incorrect; that's related to the greenhouse effect.
Differentiate between 'UV radiations' and 'Both UV and infrared'. Since ozone doesn't block infrared, the most accurate answer is 'UV radiations'.
Confirm that ozone specifically blocks the most harmful types of UV radiation (UV-B and UV-C).

Concept Tested & Keywords

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Practise the full ESIC Nursing Officer 2016 (shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.