Which portion of the electromagnetic spectrum is used to sense heat energy, spanning roughly 700 nanometers to 1 millimeter?

Which portion of the electromagnetic spectrum is used to sense heat energy, spanning roughly 700 nanometers to 1 millimeter?

• A. Visible band
• B. Infrared band
• C. Ultraviolet band
• D. Microwave band

Answer: (B)

Heat energy is sensed through infrared radiation, which is emitted by objects based on their temperature. The infrared region spans roughly 700 nanometers to 1 millimeter, sitting between visible light and microwaves. This band is where thermal radiation from everyday objects primarily lies, so infrared is what thermal imaging and heat sensing detect. Visible light reveals color and brightness, ultraviolet is higher-energy light, and microwaves are longer-wavelength energy used more for heating and communication—not for sensing heat emission in the same way. That makes infrared the correct choice.

Heat energy is sensed through infrared radiation, which is emitted by objects based on their temperature. The infrared region spans roughly 700 nanometers to 1 millimeter, sitting between visible light and microwaves. This band is where thermal radiation from everyday objects primarily lies, so infrared is what thermal imaging and heat sensing detect. Visible light reveals color and brightness, ultraviolet is higher-energy light, and microwaves are longer-wavelength energy used more for heating and communication—not for sensing heat emission in the same way. That makes infrared the correct choice.