Visible Light Wavelength Matches Algae Size

Steps:

• Visible light wavelengths range from 0.4 μm to 0.7 μm in free space.
• Convert microorganism lengths to micrometers: A (0.5 μm), B (5 μm), C (50 μm), D (100 μm).
• Compare lengths to visible wavelength range (0.4–0.7 μm).
• Identify the option where length equals a value within this range.

Why A is correct:

• Algae length of 0.5 μm falls within the visible spectrum's wavelength range of 0.4–0.7 μm, per electromagnetic wave definitions.

Why the others are wrong:

• B: 5 μm exceeds visible wavelengths, matching near-infrared.
• C: 50 μm is far larger, akin to longer infrared waves.
• D: 100 μm is much larger, corresponding to far-infrared or microwave regions.

Final answer: A