NEET Solved Paper 2016 Question 4
Question: A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of $ 15m{s^{-1}} $ . Then, the frequency of sound that the observer hears in the echo reflected from the cliff is: (Take velocity of sound in air $ =330m{s^{-1}} $ )
Options:
A) 765 Hz
B) 800 Hz
C) 838 Hz
D) 885 Hz
Show Answer
Answer:
Correct Answer: C
Solution:
- $ n’=\frac{v}{v-v _{s}}n _0 $ $ n’=\frac{330}{330-15}(800)=\frac{330\times 800}{315}=383Hz $
