JEE PYQ: Waves And Sound Question 27
Question 27 - 2019 (09 Apr Shift 2)
Two cars A and B are moving away from each other in opposite directions. Both the cars are moving with a speed of 20 ms$^{-1}$ with respect to the ground. If an observer in car A detects a frequency 2000 Hz of the sound coming from car B, what is the natural frequency of the sound source in car B?
(speed of sound in air = 340 ms$^{-1}$)
(1) 2250 Hz
(2) 2060 Hz
(3) 2300 Hz
(4) 2150 Hz
Show Answer
Answer: (1)
Solution
$f’ = f \cdot \frac{v - v_0}{v + v_s}$
$2000 = f \cdot \frac{340 - 20}{340 + 20}$
$\therefore f = 2250$ Hz
BETA
