Which range is infrared, as stated in the material?

Which range is infrared, as stated in the material?

• A. 400 to 700 nanometers
• B. 700 to 400 nanometers
• C. 1,400 to 700 nanometers
• D. 2,000 to 1,000 nanometers

Answer: (C)

Infrared light lies beyond the visible red edge, starting around 700 nm and extending into longer wavelengths. In this material, infrared is defined roughly as 700 to 1400 nm for the near-infrared range. The range listed as 1,400 to 700 nanometers covers that exact span (just written from higher to lower wavelength), so it matches the infrared region described. The other options describe visible light (400–700 nm) or extend into wavelengths outside the material’s infrared definition (like 1000–2000 nm, which goes beyond 1400 nm in this context).

Infrared light lies beyond the visible red edge, starting around 700 nm and extending into longer wavelengths. In this material, infrared is defined roughly as 700 to 1400 nm for the near-infrared range. The range listed as 1,400 to 700 nanometers covers that exact span (just written from higher to lower wavelength), so it matches the infrared region described. The other options describe visible light (400–700 nm) or extend into wavelengths outside the material’s infrared definition (like 1000–2000 nm, which goes beyond 1400 nm in this context).