Find the frequency heard by the observer if velocity of observer = 15 m/s, velocity of source = 20 m/s, frequency of sound source = 400 Hz and velocity of sound waves = 340 Hz - Clay6.com, a Free resource for your JEE, AIPMT and Board Exam preparation

Find the frequency heard by the observer if velocity of observer = 15 m/s, velocity of source = 20 m/s, frequency of sound source = 400 Hz and velocity of sound waves = 340 Hz

Answer : (d) $\;428\;Hz$ Explanation : Have to find the component of velocity of source and observer along the line joining both of them$f^{'}=(\large\frac{v+v_{0} cos 30^{0}}{v-v_{s}cos 60^{0}})\;f^{'}=(\large\frac{340 + 15 \times \large\frac{\sqrt{3}}{2}}{340-20\times \large\frac{1}{2}}) \times 400$$=427.86$$=428 (app)\;Hz$