question_answer

If we set our watch by the sound of a distant siren, will it go slow or fast?

Answer:

                The speed of sound in air has a finite value of nearly\[\text{350 m}{{\text{s}}^{\text{-1}}}\]. The sound of siren will take a finite time to reach us. Hence the watch set according to the sound of distant siren will go slow by as much time as that taken by sound to reach us.