The Doppler effect can be heard particularly clearly when a train passes by. The presence of the same effect in the generalised telegraph equation indicates the wave nature of heat transport over ...

The Doppler effect refers to a noticeable change in frequency of light or sound waves as the distance between the source and the observer changes. It is either the source or the observer of a wave is ...

We have all noticed how the horn of a speeding car changes as it approaches: each wave-peak is emitted from a closer point, so the wave is “squeezed” and the pitch increases. As the car recedes, the ...