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

${f}_{a}={f}_{o}\left(\frac{v+{v}_{o}}{v-{v}_{s}}\right)$

where,${f}_{o}$=original frequency of source

${v}_{s}$=speed of source

${v}_{o}$=speed of observer

v=speed of sound

Frequency of the hom,

${f}_{o}$=400Hz

Speed of observer in the second car,

${v}_{0}=16.5m/s$

Speed of source,

${V}_{s}$=Speed of first car

=22m/s

Frequency heard by the driver in the second car

${f}_{a}={f}_{o}\left(\frac{v+{v}_{o}}{v-{v}_{s}}\right)$

= 400 $\left(\frac{340+16.5}{340-22}\right)$

= 448Hz

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