Classifying EM waves by wavelength and frequency ranges

Steps:

• Wave X wavelength is 5.0 × 10^{-7} m (500 nm), matching visible light (400–700 nm).
• Wave Y frequency is 9 GHz (9 × 10^9 Hz), falling in microwave range (0.3–300 GHz).
• Compare to spectrum: visible for X, microwave for Y.
• Match to options: C states X visible, Y microwave.

Why C is correct:

• Visible light spans 400–700 nm wavelengths; microwaves span 0.3–300 GHz frequencies, directly placing X and Y there.

Why the others are wrong:

• A: X is not radio (longer wavelengths >1 mm); Y not ultraviolet (higher frequencies >10^{15} Hz).
• B: X not ultraviolet (shorter wavelengths <400 nm); Y not visible (frequencies 4–7.5 × 10^{14} Hz).
• D: X not microwave (longer wavelengths 1 mm–1 m); Y not radio (lower frequencies <300 MHz).

Final answer: C