A person standing on a railway platform listens to the whistles of arriving and departing trains. The whistle heard is (a)the same in both cases in all respects (b)of higher intensity when train arrives (c)of higher pitch when train arrives (d)of higher pitch when train departs
Option C. Sound is a chain of waves of strain that propagates via compressible media including air or water. (Sound can propagate thru solids as well, however there are extra modes of propagation). Sound this is perceptible with the aid of using human beings has frequencies from approximately 20 Hz to 20,000 Hz. In air at preferred temperature and strain, the corresponding wavelengths of sound waves variety from 17 m to 17 mm. During propagation, waves may be reflected, refracted, or attenuated with the aid of using the medium. Now if we take into account those cases, then the teach that is arriving in the direction of us having whistles of better pitch as it propagates thru a medium that is coming toward us however the teach that's leaving propagating thru a medium shifting in addition farfar from the listener and for this reason produced whistle of decrease pitch.
