• # question_answer A stationary source emits sound waves of frequency 500 Hz. Two observers moving along a line passing through the source detect sound to be of frequencies 480 Hz and 530 Hz. Their respective speeds are, in $m{{s}^{-1}},$ (Given speed of sound = 300 m/s) [JEE Main 10-4-2019 Morning] A) 16, 14             B) 12, 18C) 12, 16             D) 8, 18

$f=480=\frac{300-{{\text{v}}_{1}}}{300}\times 500$           $\frac{1440}{5}=300-{{\text{v}}_{1}}$           ${{\text{v}}_{1}}=\frac{60}{5}=12m/s$           $530=\frac{300+{{\text{v}}_{2}}}{300}\times 500$           $1590=1500+5{{\text{v}}_{2}}$           $5{{\text{v}}_{2}}=90$ ${{\text{v}}_{2}}=18m/s$