Which of the following is a source of UV radiation?

• A. Sun
• B. Microwave oven
• C. Incandescent bulb
• D. LED flashlights

Answer: (A)

UV radiation is the portion of the electromagnetic spectrum with wavelengths shorter than visible light. The Sun emits a broad spectrum that includes UV, making it a primary natural source of UV exposure. The other options don’t produce UV in normal use: a microwave oven emits microwaves, not UV; an incandescent bulb gives off mostly visible light and heat with negligible UV; most LED flashlights emit visible light unless they are specifically designed as UV LEDs. So, among these, the Sun is the source of UV radiation. In real-world safety, this means taking precautions for sun exposure—sunscreen, protective clothing, and sunglasses—while indoors or with typical household devices, UV output is not a concern.