Which row shows the approximate speeds at which ultraviolet waves move through air and through a vacuum?
- Aspeed in air $= 340\ \text{m s}^{-1}$; speed in a vacuum $= 3.0 \times 10^{8}\ \text{m s}^{-1}$
- Bspeed in air $= 340\ \text{m s}^{-1}$; speed in a vacuum $= 340\ \text{m s}^{-1}$
- Cspeed in air $= 3.0 \times 10^{8}\ \text{m s}^{-1}$; speed in a vacuum $= 340\ \text{m s}^{-1}$
- Dspeed in air $= 3.0 \times 10^{8}\ \text{m s}^{-1}$; speed in a vacuum $= 3.0 \times 10^{8}\ \text{m s}^{-1}$