Why can radio waves and X-rays travel at the same speed but behave so differently?
In vacuum both are electromagnetic waves, so Maxwell's equations give the same speed c.
In vacuum both are electromagnetic waves, so Maxwell's equations give the same speed c. Their frequencies differ enormously. Since E_photon = hf, X-ray photons carry much more energy and have much shorter wavelengths, allowing ionisation and fine-scale imaging. Radio photons are low energy and are useful for communication. Same wave family and speed does not mean the same interaction with matter.
Key point
Vacuum speed is common; frequency controls photon energy, wavelength and interaction.
Common mistake
explaining the different effects by assigning different vacuum speeds.
Memory tip
same speed, different frequency, very different interaction.
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