## **Core Concept**
The Woods lamp, also known as a black light, is a tool used in dermatology to diagnose fungal and bacterial infections, among other conditions. It emits ultraviolet (UV) light, specifically in the UVA range. The frequency of light emitted by the Woods lamp is crucial for its diagnostic applications.

## **Why the Correct Answer is Right**
The correct answer, , corresponds to a wavelength of 360 nm. This is within the UVA range of the ultraviolet spectrum, which is approximately 320-400 nm. The Woods lamp is designed to emit light in this range because it helps in diagnosing conditions like fungal infections (e.g., ringworm) and bacterial infections (e.g., Pseudomonas), which fluoresce under UVA light. The UVA light does not cause significant damage to tissues and is useful for diagnostic purposes.

## **Why Each Wrong Option is Incorrect**
- **Option A:** . This wavelength is too short and falls into the UVC range, which is not used for diagnostic purposes due to its harmful effects on tissues and being mostly absorbed by the atmosphere.
- **Option B:** . This wavelength is in the UVB range, which is more associated with causing sunburn and less useful for the diagnostic applications of a Woods lamp.
- **Option D:** . This option seems to be incomplete but if suggesting a longer wavelength, it would be less specific for the diagnostic applications attributed to the UVA range.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the Woods lamp is used for diagnosing conditions that fluoresce under UVA light. A classic example is the diagnosis of **Microsporum canis** infections, which fluoresce a bright blue-green under the Woods lamp. This is a high-yield fact for dermatology and can be a memorable point for exams.

## **Correct Answer:** .