Visible Spectrum Wavelengths for Colors

Steps:

• Recall the visible light spectrum ranges from 400 nm (violet) to 700 nm (red).
• Identify green light occupies 500–570 nm within this range.
• Note typical peak sensitivity for green is around 550 nm.
• Compare choices to this range for the closest match.

Why B is correct:

• 540 nm falls squarely in the 500–570 nm band defined for green light in the visible spectrum.

Why the others are wrong:

• A: 280 nm is in the ultraviolet range, below visible light.
• C: 780 nm is in the near-infrared range, beyond red visible light.
• D: 620 nm corresponds to orange-red hues, not green.

Final answer: B