Electromagnetic spectrum wavelength order

Steps:

• Recall EM spectrum: wavelengths decrease from radio waves (longest) to gamma rays (shortest).
• Locate regions: radio waves > infrared > visible light > ultraviolet > X-rays.
• Compare visible colors: red > green > blue (longer to shorter wavelengths).
• Assess ranges: radio waves span ~1 mm to >100 km; X-rays ~0.01–10 nm.

Why D is correct:

• EM spectrum arranges waves by decreasing wavelength; X-rays (10⁻¹² to 10⁻⁸ m) occupy a shorter range than radio waves (10⁻³ to 10⁵ m), per standard spectral classification.

Why the others are wrong:

• A: X-rays (~0.01 nm) have shorter wavelengths than green light (~500 nm).
• B: Red light (~700 nm) has longer wavelength than green light (~500 nm).
• C: Radio waves span much longer wavelengths (up to kilometers) than infrared (~700 nm to 1 mm).

Final answer: D