wave_mechanics dopplers_effect Question 61
Question: A person carrying a whistle emitting continuously a note of 272 Hz is running towards a reflecting surface with a speed of 18 km/hour. The speed of sound in air is $ 345m{{s}^{-1}} $ . The number of beats heard by him is
[Kerala (Engg.) 2002]
Options:
A) 4
B) 6
C) 8
D) 3
Show Answer
Answer:
Correct Answer: C
Solution:
According the concept of sound image $ n’=\frac{v+{v _{\text{person}}}}{v-{v _{\text{person}}}}.272=\frac{345+5}{345-5}\times 272=280 $ Hz $ \Delta n= $ Number of beats =280 ? 272 = 8 Hz
BETA
