Questions: Some of the light that atomic hydrogen can emit has wavelengths of 21 cm (radio), 656 nm (red), 1.88 µm (infrared), 410 nm (violet), and 122 nm (ultraviolet). Arrange these from fastest speed to slowest speed in empty space. cm=10^-2 m (centimeters), µm=10^-6 m (microns), and nm=10^-9 m (nanometers). There is not enough information to determine the speeds. 122 nm, 410 nm, 656 nm, 1.88 µm, 21 cm 21 cm, 1.88 µm, 656 nm, 410 nm, 122 nm 1.88 µm, 21 cm, 122 nm, 410 nm, 656 nm They all travel at the same speed.

Transcript text: Some of the light that atomic hydrogen can emit has wavelengths of 21 cm (radio), 656 nm (red), $1.88 \mu \mathrm{~m}$ (infrared), 410 nm (violet), and 122 nm (ultraviolet). Arrange these from fastest speed to slowest speed in empty space. $\mathrm{cm}=10^{-2} \mathrm{~m}$ (centimeters), $\mu \mathrm{m}=10^{-6} \mathrm{~m}$ (microns), and $\mathrm{nm}=10^{-9} \mathrm{~m}$ (nanometers). There is not enough information to determine the speeds. $122 \mathrm{~nm}, 410 \mathrm{~nm}, 656 \mathrm{~nm}, 1.88 \mu \mathrm{~m}, 21 \mathrm{~cm}$ $21 \mathrm{~cm}, 1.88 \mu \mathrm{~m}, 656 \mathrm{~nm}, 410 \mathrm{~nm}, 122 \mathrm{~nm}$ $1.88 \mu \mathrm{~m}, 21 \mathrm{~cm}, 122 \mathrm{~nm}, 410 \mathrm{~nm}, 656 \mathrm{~nm}$ They all travel at the same speed.