A car P travelling at sounds its horn at a frequency of 400 Hz. Another car Q is travelling behind the first car in the same direction with a velocity . The frequency heard by the passenger of the car Q is approximately [Take, velocity of sound ]
- (A)514 Hz
- (B)421 Hz✓ Correct
- (C)485 Hz
- (D)471 Hz
Answer: (B)
Solution
Using the Doppler effect formula for sound: , where is the observer velocity (car Q, 40 m/s), is the source velocity (car P, 20 m/s), and m/s. Substituting: Hz.
JEE Main · 2023 · 11 Apr 2023 · Shift 2 · Single correct option