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]

(a)350Hz

(b)361Hz

(c)411Hz

(d)448Hz

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

fa=fov+vov-vs

where,fo=original frequency of source

          vs=speed of source 

          vo=speed of observer

            v=speed of sound 

 Frequency of the hom, 

fo=400Hz

Speed of observer in the second car,

            v0=16.5m/s

Speed of source,

                  Vs=Speed of first car

                      =22m/s

Frequency heard by the driver in the second car 

fa=fov+vov-vs

 = 400 340+16.5340-22

= 448Hz

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