Two cars moving in opposite directions approach each other with speed of 22m/s and 16.5 m/s respectively. The driver of the first car blows a horn having a frequency 400 Hz. The frequency heard by the driver of the second car is [velocity of sound 340m/s]





(d) Thinking Proces When both source and observer are moving towards each other, apparent frequency is given by


where,fo=original frequency of source

          vs=speed of source 

          vo=speed of observer

            v=speed of sound 

 Frequency of the hom, 


Speed of observer in the second car,


Speed of source,

                  Vs=Speed of first car


Frequency heard by the driver in the second car 


 = 400 340+16.5340-22

= 448Hz

Difficulty Level:

  • 12%
  • 24%
  • 22%
  • 44%