A speeding motorcyclist sees traffic jam ahead of him. He slows down to 36 km/hour. He finds that traffic has eased and a car moving a head of him at 18 km/hour is honking at a frequency of 1392 Hz. If the speed of sound is 343 m/s, the frequency of the honk as heard by him will be:
1332 Hz
1372 Hz
1412 Hz
1464 Hz
As we discussed
frequency of sound when source is moving away and observer is moving towards the source -
- wherein
Speed of sound
Speed of observer
speed of source
Original frequency
apparent frequency
According to doppler's effect
Option 1)
1332 Hz
Incorrect
Option 2)
1372 Hz
Incorrect
Option 3)
1412 Hz
Correct
Option 4)
1464 Hz
Incorrect