Diffraction affects radio and television signals. Long wave radio signals are much less affected by buildings, hills, tunnels etc. than those of short wave or VHF radio, or television.

Speed\((v)\) is in metres per second \(m\,s^{-1}\), distance \((d)\) in metres \((m)\) and time\( (t)\) in seconds \((s)\). Measuring the time taken for a sound wave ...