Question:
Which of the following rays is emitted by a human body?
Which of the following rays is emitted by a human body?
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Objects at room/body temperature emit mostly infrared radiation. Thermal cameras detect this IR radiation.
Updated On: Jan 3, 2026
- X-rays
- UV rays
- Visible rays
- IR rays
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The Correct Option is D
Solution and Explanation
Step 1: Understand thermal radiation.
Every object having temperature above \(0\,K\) emits electromagnetic radiation due to thermal motion of particles.
Step 2: Human body temperature range.
Human body temperature is approximately \(37^\circ C \approx 310\,K\).
At this temperature, the peak wavelength lies in infrared region (according to Wien's displacement law).
Step 3: Eliminate incorrect options.
X-rays: require extremely high energy processes, not produced naturally by body.
UV rays: higher energy than IR and not emitted strongly at \(310\,K\).
Visible rays: body does not glow visibly at normal temperature.
IR rays: emitted strongly due to body heat and detected by thermal cameras.
Final Answer: \[ \boxed{\text{IR rays}} \]
Every object having temperature above \(0\,K\) emits electromagnetic radiation due to thermal motion of particles.
Step 2: Human body temperature range.
Human body temperature is approximately \(37^\circ C \approx 310\,K\).
At this temperature, the peak wavelength lies in infrared region (according to Wien's displacement law).
Step 3: Eliminate incorrect options.
X-rays: require extremely high energy processes, not produced naturally by body.
UV rays: higher energy than IR and not emitted strongly at \(310\,K\).
Visible rays: body does not glow visibly at normal temperature.
IR rays: emitted strongly due to body heat and detected by thermal cameras.
Final Answer: \[ \boxed{\text{IR rays}} \]
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