Electromagnetic waves share the same speed in air

Steps:

• Identify microwaves and radio waves as electromagnetic waves, all traveling at ~3.0 × 10^8 m/s in air.
• Note radio waves have lower frequencies than microwaves (which are ~10^{10} Hz).
• Select option with frequency << 10^{10} Hz but matching speed of 3.0 × 10^8 m/s.
• Confirm B fits: low frequency (e.g., 3.0 × 10^6 Hz, typical for radio) and correct speed.

Why B is correct:

• Matches the universal speed of electromagnetic waves in air (c ≈ 3.0 × 10^8 m/s) with a plausible low radio frequency.

Why the others are wrong:

• A: Speed of 1500 m/s is for sound, not electromagnetic waves.
• C: Speed of 5.0 × 10 m/s is far too slow for any electromagnetic wave.
• D: Frequency matches microwave range, not lower for radio waves.

Final answer: B