Q

# What physical quantity is the same for X-rays of wavelength 10 ^ 10 m, red light of wavelength 6800 Å and radiowaves of wavelength 500m

3. What physical quantity is the same for X-rays of wavelength $10 ^{-10}$ m, red light of wavelength 6800 $\dot{A}$ and radiowaves of wavelength 500m?

The speed with which these electromagnetic waves travel in a vacuum will be the same and will be equal to $3\times 10^{8}ms^{-1}$ (speed of light in vacuum).